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Linux Without Limits: IBM Launch LinuxONE Mainframes
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================================================================================
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LinuxONE Emperor MainframeGood news for Ubuntu’s server team today as [IBM launch the LinuxONE][1] a Linux-only mainframe that is also able to run Ubuntu.
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The largest of the LinuxONE systems launched by IBM is called ‘Emperor’ and can scale up to 8000 virtual machines or tens of thousands of containers – a possible record for any one single Linux system.
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The LinuxONE is described by IBM as a ‘game changer’ that ‘unleashes the potential of Linux for business’.
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IBM and Canonical are working together on the creation of an Ubuntu distribution for LinuxONE and other IBM z Systems. Ubuntu will join RedHat and SUSE as ‘premier Linux distributions’ on IBM z.
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Alongside the ‘Emperor’ IBM is also offering the LinuxONE Rockhopper, a smaller mainframe for medium-sized businesses and organisations.
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IBM is the market leader in mainframes and commands over 90% of the mainframe market.
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注：youtube 视频
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<iframe width="750" height="422" frameborder="0" allowfullscreen="" src="https://www.youtube.com/embed/2ABfNrWs-ns?feature=oembed"></iframe>
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### What Is a Mainframe Computer Used For? ###
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The computer you’re reading this article on would be dwarfed by a ‘big iron’ mainframe. They are large, hulking great cabinets packed full of high-end components, custom designed technology and dizzying amounts of storage (that is data storage, not ample room for pens and rulers).
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Mainframes computers are used by large organizations and businesses to process and store large amounts of data, crunch through statistics, and handle large-scale transaction processing.
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### ‘World’s Fastest Processor’ ###
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IBM has teamed up with Canonical Ltd to use Ubuntu on the LinuxONE and other IBM z Systems.
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The LinuxONE Emperor uses the IBM z13 processor. The chip, announced back in January, is said to be the world’s fastest microprocessor. It is able to deliver transaction response times in the milliseconds.
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But as well as being well equipped to handle for high-volume mobile transactions, the z13 inside the LinuxONE is also an ideal cloud system.
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It can handle more than 50 virtual servers per core for a total of 8000 virtual servers, making it a cheaper, greener and more performant way to scale-out to the cloud.
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**You don’t have to be a CIO or mainframe spotter to appreciate this announcement. The possibilities LinuxONE provides are clear enough. **
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Source: [Reuters (h/t @popey)][2]
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--------------------------------------------------------------------------------
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via: http://www.omgubuntu.co.uk/2015/08/ibm-linuxone-mainframe-ubuntu-partnership
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|
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作者：[Joey-Elijah Sneddon][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:https://plus.google.com/117485690627814051450/?rel=author
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[1]:http://www-03.ibm.com/systems/z/announcement.html
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[2]:http://www.reuters.com/article/2015/08/17/us-ibm-linuxone-idUSKCN0QM09P20150817
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@ -0,0 +1,46 @@
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Ubuntu Linux is coming to IBM mainframes
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================================================================================
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SEATTLE -- It's finally happened. At [LinuxCon][1], IBM and [Canonical][2] announced that [Ubuntu Linux][3] will soon be running on IBM mainframes.
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You'll soon to be able to get your IBM mainframe in Ubuntu Linux orange
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According to Ross Mauri, IBM's General Manager of System z, and Mark Shuttleworth, Canonical and Ubuntu's founder, this move came about because of customer demand. For over a decade, [Red Hat Enterprise Linux (RHEL)][4] and [SUSE Linux Enterprise Server (SLES)][5] were the only supported IBM mainframe Linux distributions.
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As Ubuntu matured, more and more businesses turned to it for the enterprise Linux, and more and more of them wanted it on IBM big iron hardware. In particular, banks wanted Ubuntu there. Soon, financial CIOs will have their wish granted.
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In an interview Shuttleworth said that Ubuntu Linux will be available on the mainframe by April 2016 in the next long-term support version of Ubuntu: Ubuntu 16.04. Canonical and IBM already took the first move in this direction in late 2014 by bringing [Ubuntu to IBM's POWER][6] architecture.
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Before that, Canonical and IBM almost signed the dotted line to bring [Ubuntu to IBM mainframes in 2011][7] but that deal was never finalized. This time, it's happening.
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Jane Silber, Canonical's CEO, explained in a statement, "Our [expansion of Ubuntu platform][8] support to [IBM z Systems][9] is a recognition of the number of customers that count on z Systems to run their businesses, and the maturity the hybrid cloud is reaching in the marketplace.
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**Silber continued:**
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> With support of z Systems, including [LinuxONE][10], Canonical is also expanding our relationship with IBM, building on our support for the POWER architecture and OpenPOWER ecosystem. Just as Power Systems clients are now benefiting from the scaleout capabilities of Ubuntu, and our agile development process which results in first to market support of new technologies such as CAPI (Coherent Accelerator Processor Interface) on POWER8, z Systems clients can expect the same rapid rollout of technology advancements, and benefit from [Juju][11] and our other cloud tools to enable faster delivery of new services to end users. In addition, our collaboration with IBM includes the enablement of scale-out deployment of many IBM software solutions with Juju Charms. Mainframe clients will delight in having a wealth of 'charmed' IBM solutions, other software provider products, and open source solutions, deployable on mainframes via Juju.
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Shuttleworth expects Ubuntu on z to be very successful. "It's blazingly fast, and with its support for OpenStack, people who want exceptional cloud region performance will be very happy.
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--------------------------------------------------------------------------------
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via: http://www.zdnet.com/article/ubuntu-linux-is-coming-to-the-mainframe/#ftag=RSSbaffb68
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作者：[Steven J. Vaughan-Nichols][a]
|
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译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
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|
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[a]:http://www.zdnet.com/meet-the-team/us/steven-j-vaughan-nichols/
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[1]:http://events.linuxfoundation.org/events/linuxcon-north-america
|
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[2]:http://www.canonical.com/
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[3]:http://www.ubuntu.comj/
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[4]:http://www.redhat.com/en/technologies/linux-platforms/enterprise-linux
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[5]:https://www.suse.com/products/server/
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[6]:http://www.zdnet.com/article/ibm-doubles-down-on-linux/
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[7]:http://www.zdnet.com/article/mainframe-ubuntu-linux/
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[8]:https://insights.ubuntu.com/2015/08/17/ibm-and-canonical-plan-ubuntu-support-on-ibm-z-systems-mainframe/
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[9]:http://www-03.ibm.com/systems/uk/z/
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[10]:http://www.zdnet.com/article/linuxone-ibms-new-linux-mainframes/
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[11]:https://jujucharms.com/
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A Linux User Using ‘Windows 10′ After More than 8 Years – See Comparison
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================================================================================
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Windows 10 is the newest member of windows NT family of which general availability was made on July 29, 2015. It is the successor of Windows 8.1. Windows 10 is supported on Intel Architecture 32 bit, AMD64 and ARMv7 processors.
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Windows 10 and Linux Comparison
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As a Linux-user for more than 8 continuous years, I thought to test Windows 10, as it is making a lots of news these days. This article is a breakthrough of my observation. I will be seeing everything from the perspective of a Linux user so you may find it a bit biased towards Linux but with absolutely no false information.
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1. I searched Google with the text “download windows 10” and clicked the first link.
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Search Windows 10
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You may directly go to link : [https://www.microsoft.com/en-us/software-download/windows10ISO][1]
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2. I was supposed to select a edition from ‘windows 10‘, ‘windows 10 KN‘, ‘windows 10 N‘ and ‘windows 10 single language‘.
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Select Windows 10 Edition
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For those who want to know details of different editions of Windows 10, here is the brief details of editions.
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- Windows 10 – Contains everything offered by Microsoft for this OS.
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- Windows 10N – This edition comes without Media-player.
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- Windows 10KN – This edition comes without media playing capabilities.
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- Windows 10 Single Language – Only one Language Pre-installed.
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3. I selected the first option ‘Windows 10‘ and clicked ‘Confirm‘. Then I was supposed to select a product language. I choose ‘English‘.
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I was provided with Two Download Links. One for 32-bit and other for 64-bit. I clicked 64-bit, as per my architecture.
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Download Windows 10
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With my download speed (15Mbps), it took me 3 long hours to download it. Unfortunately there were no torrent file to download the OS, which could otherwise have made the overall process smooth. The OS iso image size is 3.8 GB.
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I could not find an image of smaller size but again the truth is there don’t exist net-installer image like things for Windows. Also there is no way to calculate hash value after the iso image has been downloaded.
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Wonder why so ignorance from windows on such issues. To verify if the iso is downloaded correctly I need to write the image to a disk or to a USB flash drive and then boot my system and keep my finger crossed till the setup is finished.
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Lets start. I made my USB flash drive bootable with the windows 10 iso using dd command, as:
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# dd if=/home/avi/Downloads/Win10_English_x64.iso of=/dev/sdb1 bs=512M; sync
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It took a few minutes to complete the process. I then rebooted the system and choose to boot from USB flash Drive in my UEFI (BIOS) settings.
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#### System Requirements ####
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|
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If you are upgrading
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- Upgrade supported only from Windows 7 SP1 or Windows 8.1
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|
||||
If you are fresh Installing
|
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|
||||
- Processor: 1GHz or faster
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- RAM : 1GB and Above(32-bit), 2GB and Above(64-bit)
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- HDD: 16GB and Above(32-bit), 20GB and Above(64-bit)
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- Graphic card: DirectX 9 or later + WDDM 1.0 Driver
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### Installation of Windows 10 ###
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1. Windows 10 boots. Yet again they changed the logo. Also no information on whats going on.
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Windows 10 Logo
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2. Selected Language to install, Time & currency format and keyboard & Input methods before clicking Next.
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Select Language and Time
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3. And then ‘Install Now‘ Menu.
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Install Windows 10
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4. The next screen is asking for Product key. I clicked ‘skip’.
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Windows 10 Product Key
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5. Choose from a listed OS. I chose ‘windows 10 pro‘.
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Select Install Operating System
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6. oh yes the license agreement. Put a check mark against ‘I accept the license terms‘ and click next.
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Accept License
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7. Next was to upgrade (to windows 10 from previous versions of windows) and Install Windows. Don’t know why custom: Windows Install only is suggested as advanced by windows. Anyway I chose to Install windows only.
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Select Installation Type
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8. Selected the file-system and clicked ‘next’.
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Select Install Drive
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9. The installer started to copy files, getting files ready for installation, installing features, installing updates and finishing up. It would be better if the installer would have shown verbose output on the action is it taking.
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|
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|
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|
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Installing Windows
|
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|
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10. And then windows restarted. They said reboot was needed to continue.
|
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|
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|
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|
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Windows Installation Process
|
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|
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11. And then all I got was the below screen which reads “Getting Ready”. It took 5+ minutes at this point. No idea what was going on. No output.
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Windows Getting Ready
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12. yet again, it was time to “Enter Product Key”. I clicked “Do this later” and then used expressed settings.
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Enter Product Key
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|
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Select Express Settings
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14. And then three more output screens, where I as a Linuxer expected that the Installer will tell me what it is doing but all in vain.
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|
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|
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Loading Windows
|
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|
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|
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Getting Updates
|
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|
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|
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|
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Still Loading Windows
|
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15. And then the installer wanted to know who owns this machine “My organization” or I myself. Chose “I own it” and then next.
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|
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|
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Select Organization
|
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|
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16. Installer prompted me to join “Azure Ad” or “Join a domain”, before I can click ‘continue’. I chooses the later option.
|
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|
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|
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|
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Connect Windows
|
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|
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17. The Installer wants me to create an account. So I entered user_name and clicked ‘Next‘, I was expecting an error message that I must enter a password.
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|
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|
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Create Account
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|
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18. To my surprise Windows didn’t even showed warning/notification that I must create password. Such a negligence. Anyway I got my desktop.
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|
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Windows 10 Desktop
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#### Experience of a Linux-user (Myself) till now ####
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|
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- No Net-installer Image
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- Image size too heavy
|
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- No way to check the integrity of iso downloaded (no hash check)
|
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- The booting and installation remains same as it was in XP, Windows 7 and 8 perhaps.
|
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- As usual no output on what windows Installer is doing – What file copying or what package installing.
|
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- Installation was straight forward and easy as compared to the installation of a Linux distribution.
|
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|
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### Windows 10 Testing ###
|
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|
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19. The default Desktop is clean. It has a recycle bin Icon on the default desktop. Search web directly from the desktop itself. Additionally icons for Task viewing, Internet browsing, folder browsing and Microsoft store is there. As usual notification bar is present on the bottom right to sum up desktop.
|
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|
||||
|
||||
|
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Deskop Shortcut Icons
|
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|
||||
20. Internet Explorer replaced with Microsoft Edge. Windows 10 has replace the legacy web browser Internet Explorer also known as IE with Edge aka project spartan.
|
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|
||||
|
||||
|
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Microsoft Edge Browser
|
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|
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It is fast at least as compared to IE (as it seems it testing). Familiar user Interface. The home screen contains news feed updates. There is also a search bar title that reads ‘Where to next?‘. The browser loads time is considerably low which result in improving overall speed and performance. The memory usages of Edge seems normal.
|
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|
||||
|
||||
|
||||
Windows Performance
|
||||
|
||||
Edge has got cortana – Intelligent Personal Assistant, Support for chrome-extension, web Note – Take notes while Browsing, Share – Right from the tab without opening any other TAB.
|
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|
||||
#### Experience of a Linux-user (Myself) on this point ####
|
||||
|
||||
21. Microsoft has really improved web browsing. Lets see how stable and fine it remains. It don’t lag as of now.
|
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|
||||
22. Though RAM usages by Edge was fine for me, a lots of users are complaining that Edge is notorious for Excessive RAM Usages.
|
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|
||||
23. Difficult to say at this point if Edge is ready to compete with Chrome and/or Firefox at this point of time. Lets see what future unfolds.
|
||||
|
||||
#### A few more Virtual Tour ####
|
||||
|
||||
24. Start Menu redesigned – Seems clear and effective. Metro icons make it live. Populated with most commonly applications viz., Calendar, Mail, Edge, Photos, Contact, Temperature, Companion suite, OneNote, Store, Xbox, Music, Movies & TV, Money, News, Store, etc.
|
||||
|
||||
|
||||
|
||||
Windows Look and Feel
|
||||
|
||||
In Linux on Gnome Desktop Environment, I use to search required applications simply by pressing windows key and then type the name of the application.
|
||||
|
||||
|
||||
|
||||
Search Within Desktop
|
||||
|
||||
25. File Explorer – seems clear Designing. Edges are sharp. In the left pane there is link to quick access folders.
|
||||
|
||||
|
||||
|
||||
Windows File Explorer
|
||||
|
||||
Equally clear and effective file explorer on Gnome Desktop Environment on Linux. Removed UN-necessary graphics and images from icons is a plus point.
|
||||
|
||||
|
||||
|
||||
File Browser on Gnome
|
||||
|
||||
26. Settings – Though the settings are a bit refined on Windows 10, you may compare it with the settings on a Linux Box.
|
||||
|
||||
**Settings on Windows**
|
||||
|
||||
|
||||
|
||||
Windows 10 Settings
|
||||
|
||||
**Setting on Linux Gnome**
|
||||
|
||||
|
||||
|
||||
Gnome Settings
|
||||
|
||||
27. List of Applications – List of Application on Linux is better than what they use to provide (based upon my memory, when I was a regular windows user) but still it stands low as compared to how Gnome3 list application.
|
||||
|
||||
**Application Listed by Windows**
|
||||
|
||||
|
||||
|
||||
Application List on Windows 10
|
||||
|
||||
**Application Listed by Gnome3 on Linux**
|
||||
|
||||
|
||||
|
||||
Gnome Application List on Linux
|
||||
|
||||
28. Virtual Desktop – Virtual Desktop feature of Windows 10 is one of those topic which are very much talked about these days.
|
||||
|
||||
Here is the virtual Desktop in Windows 10.
|
||||
|
||||
|
||||
|
||||
Windows Virtual Desktop
|
||||
|
||||
and the virtual Desktop on Linux we are using for more than 2 decades.
|
||||
|
||||
|
||||
|
||||
Virtual Desktop on Linux
|
||||
|
||||
#### A few other features of Windows 10 ####
|
||||
|
||||
29. Windows 10 comes with wi-fi sense. It shares your password with others. Anyone who is in the range of your wi-fi and connected to you over Skype, Outlook, Hotmail or Facebook can be granted access to your wifi network. And mind it this feature has been added as a feature by microsoft to save time and hassle-free connection.
|
||||
|
||||
In a reply to question raised by Tecmint, Microsoft said – The user has to agree to enable wifi sense, everytime on a new network. oh! What a pathetic taste as far as security is concerned. I am not convinced.
|
||||
|
||||
30. Up-gradation from Windows 7 and Windows 8.1 is free though the retail cost of Home and pro editions are approximately $119 and $199 respectively.
|
||||
|
||||
31. Microsoft released first cumulative update for windows 10, which is said to put system into endless crash loop for a few people. Windows perhaps don’t understand such problem or don’t want to work on that part don’t know why.
|
||||
|
||||
32. Microsoft’s inbuilt utility to block/hide unwanted updates don’t work in my case. This means If a update is there, there is no way to block/hide it. Sorry windows users!
|
||||
|
||||
#### A few features native to Linux that windows 10 have ####
|
||||
|
||||
Windows 10 has a lots of features that were taken directly from Linux. If Linux were not released under GNU License perhaps Microsoft would never had the below features.
|
||||
|
||||
33. Command-line package management – Yup! You heard it right. Windows 10 has a built-in package management. It works only in Windows Power Shell. OneGet is the official package manager for windows. Windows package manager in action.
|
||||
|
||||
|
||||
|
||||
Windows 10 Package Manager
|
||||
|
||||
- Border-less windows
|
||||
- Flat Icons
|
||||
- Virtual Desktop
|
||||
- One search for Online+offline search
|
||||
- Convergence of mobile and desktop OS
|
||||
|
||||
### Overall Conclusion ###
|
||||
|
||||
- Improved responsiveness
|
||||
- Well implemented Animation
|
||||
- low on resource
|
||||
- Improved battery life
|
||||
- Microsoft Edge web-browser is rock solid
|
||||
- Supported on Raspberry pi 2.
|
||||
- It is good because windows 8/8.1 was not upto mark and really bad.
|
||||
- It is a the same old wine in new bottle. Almost the same things with brushed up icons.
|
||||
|
||||
What my testing suggest is Windows 10 has improved on a few things like look and feel (as windows always did), +1 for Project spartan, Virtual Desktop, Command-line package management, one search for online and offline search. It is overall an improved product but those who thinks that Windows 10 will prove to be the last nail in the coffin of Linux are mistaken.
|
||||
|
||||
Linux is years ahead of Windows. Their approach is different. In near future windows won’t stand anywhere around Linux and there is nothing for which a Linux user need to go to Windows 10.
|
||||
|
||||
That’s all for now. Hope you liked the post. I will be here again with another interesting post you people will love to read. Provide us with your valuable feedback in the comments below.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/a-linux-user-using-windows-10-after-more-than-8-years-see-comparison/
|
||||
|
||||
作者：[vishek Kumar][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/avishek/
|
||||
[1]:https://www.microsoft.com/en-us/software-download/windows10ISO
|
||||
@ -0,0 +1,109 @@
|
||||
Debian GNU/Linux Birthday : A 22 Years of Journey and Still Counting…
|
||||
================================================================================
|
||||
On 16th August 2015, the Debian project has celebrated its 22nd anniversary, making it one of the oldest popular distribution in open source world. Debian project was conceived and founded in the year 1993 by Ian Murdock. By that time Slackware had already made a remarkable presence as one of the earliest Linux Distribution.
|
||||
|
||||
|
||||
|
||||
Happy 22nd Birthday to Debian Linux
|
||||
|
||||
Ian Ashley Murdock, an American Software Engineer by profession, conceived the idea of Debian project, when he was a student of Purdue University. He named the project Debian after the name of his then-girlfriend Debra Lynn (Deb) and his name. He later married her and then got divorced in January 2008.
|
||||
|
||||
|
||||
|
||||
Debian Creator: Ian Murdock
|
||||
|
||||
Ian is currently serving as Vice President of Platform and Development Community at ExactTarget.
|
||||
|
||||
Debian (as Slackware) was the result of unavailability of up-to mark Linux Distribution, that time. Ian in an interview said – “Providing the first class Product without profit would be the sole aim of Debian Project. Even Linux was not reliable and up-to mark that time. I Remember…. Moving files between file-system and dealing with voluminous file would often result in Kernel Panic. However the project Linux was promising. The availability of Source Code freely and the potential it seemed was qualitative.”
|
||||
|
||||
I remember … like everyone else I wanted to solve problem, run something like UNIX at home, but it was not possible…neither financially nor legally, in the other sense . Then I come to know about GNU kernel Development and its non-association with any kind of legal issues, he added. He was sponsored by Free Software Foundation (FSF) in the early days when he was working on Debian, it also helped Debian to take a giant step though Ian needed to finish his degree and hence quited FSF roughly after one year of sponsorship.
|
||||
|
||||
### Debian Development History ###
|
||||
|
||||
- **Debian 0.01 – 0.09** : Released between August 1993 – December 1993.
|
||||
- **Debian 0.91 ** – Released in January 1994 with primitive package system, No dependencies.
|
||||
- **Debian 0.93 rc5** : March 1995. It is the first modern release of Debian, dpkg was used to install and maintain packages after base system installation.
|
||||
- **Debian 0.93 rc6**: Released in November 1995. It was last a.out release, deselect made an appearance for the first time – 60 developers were maintaining packages, then at that time.
|
||||
- **Debian 1.1**: Released in June 1996. Code name – Buzz, Packages count – 474, Package Manager dpkg, Kernel 2.0, ELF.
|
||||
- **Debian 1.2**: Released in December 1996. Code name – Rex, Packages count – 848, Developers Count – 120.
|
||||
- **Debian 1.3**: Released in July 1997. Code name – Bo, package count 974, Developers count – 200.
|
||||
- **Debian 2.0**: Released in July 1998. Code name: Hamm, Support for architecture – Intel i386 and Motorola 68000 series, Number of Packages: 1500+, Number of Developers: 400+, glibc included.
|
||||
- **Debian 2.1**: Released on March 09, 1999. Code name – slink, support architecture Alpha and Sparc, apt came in picture, Number of package – 2250.
|
||||
- **Debian 2.2**: Released on August 15, 2000. Code name – Potato, Supported architecture – Intel i386, Motorola 68000 series, Alpha, SUN Sparc, PowerPC and ARM architecture. Number of packages: 3900+ (binary) and 2600+ (Source), Number of Developers – 450. There were a group of people studied and came with an article called Counting potatoes, which shows – How a free software effort could lead to a modern operating system despite all the issues around it.
|
||||
- **Debian 3.0** : Released on July 19th, 2002. Code name – woody, Architecture supported increased– HP, PA_RISC, IA-64, MIPS and IBM, First release in DVD, Package Count – 8500+, Developers Count – 900+, Cryptography.
|
||||
- **Debian 3.1**: Release on June 6th, 2005. Code name – sarge, Architecture support – same as woody + AMD64 – Unofficial Port released, Kernel – 2.4 qnd 2.6 series, Number of Packages: 15000+, Number of Developers : 1500+, packages like – OpenOffice Suite, Firefox Browser, Thunderbird, Gnome 2.8, kernel 3.3 Advanced Installation Support: RAID, XFS, LVM, Modular Installer.
|
||||
- **Debian 4.0**: Released on April 8th, 2007. Code name – etch, architecture support – same as sarge, included AMD64. Number of packages: 18,200+ Developers count : 1030+, Graphical Installer.
|
||||
- **Debian 5.0**: Released on February 14th, 2009. Code name – lenny, Architecture Support – Same as before + ARM. Number of packages: 23000+, Developers Count: 1010+.
|
||||
- **Debian 6.0** : Released on July 29th, 2009. Code name – squeeze, Package included : kernel 2.6.32, Gnome 2.3. Xorg 7.5, DKMS included, Dependency-based. Architecture : Same as pervious + kfreebsd-i386 and kfreebsd-amd64, Dependency based booting.
|
||||
- **Debian 7.0**: Released on may 4, 2013. Code name: wheezy, Support for Multiarch, Tools for private cloud, Improved Installer, Third party repo need removed, full featured multimedia-codec, Kernel 3.2, Xen Hypervisor 4.1.4 Package Count: 37400+.
|
||||
- **Debian 8.0**: Released on May 25, 2015 and Code name: Jessie, Systemd as the default init system, powered by Kernel 3.16, fast booting, cgroups for services, possibility of isolating part of the services, 43000+ packages. Sysvinit init system available in Jessie.
|
||||
|
||||
**Note**: Linux Kernel initial release was on October 05, 1991 and Debian initial release was on September 15, 1993. So, Debian is there for 22 Years running Linux Kernel which is there for 24 years.
|
||||
|
||||
### Debian Facts ###
|
||||
|
||||
Year 1994 was spent on organizing and managing Debian project so that it would be easy for others to contribute. Hence no release for users were made this year however there were certain internal release.
|
||||
|
||||
Debian 1.0 was never released. A CDROM manufacturer company by mistakenly labelled an unreleased version as Debian 1.0. Hence to avoid confusion Debian 1.0 was released as Debian 1.1 and since then only the concept of official CDROM images came into existence.
|
||||
|
||||
Each release of Debian is a character of Toy Story.
|
||||
|
||||
Debian remains available in old stable, stable, testing and experimental, all the time.
|
||||
|
||||
The Debian Project continues to work on the unstable distribution (codenamed sid, after the evil kid from the Toy Story). Sid is the permanent name for the unstable distribution and is remains ‘Still In Development’. The testing release is intended to become the next stable release and is currently codenamed jessie.
|
||||
|
||||
Debian official distribution includes only Free and OpenSource Software and nothing else. However the availability of contrib and Non-free Packages makes it possible to install those packages which are free but their dependencies are not licensed free (contrib) and Packages licensed under non-free softwares.
|
||||
|
||||
Debian is the mother of a lot of Linux distribution. Some of these Includes:
|
||||
|
||||
- Damn Small Linux
|
||||
- KNOPPIX
|
||||
- Linux Advanced
|
||||
- MEPIS
|
||||
- Ubuntu
|
||||
- 64studio (No more active)
|
||||
- LMDE
|
||||
|
||||
Debian is the world’s largest non commercial Linux Distribution. It is written in C (32.1%) programming language and rest in 70 other languages.
|
||||
|
||||
|
||||
|
||||
Debian Contribution
|
||||
|
||||
Image Source: [Xmodulo][1]
|
||||
|
||||
Debian project contains 68.5 million actual loc (lines of code) + 4.5 million lines of comments and white spaces.
|
||||
|
||||
International Space station dropped Windows & Red Hat for adopting Debian – These astronauts are using one release back – now “squeeze” for stability and strength from community.
|
||||
|
||||
Thank God! Who would have heard the scream from space on Windows Metro Screen :P
|
||||
|
||||
#### The Black Wednesday ####
|
||||
|
||||
On November 20th, 2002 the University of Twente Network Operation Center (NOC) caught fire. The fire department gave up protecting the server area. NOC hosted satie.debian.org which included Security, non-US archive, New Maintainer, quality assurance, databases – Everything was turned to ashes. Later these services were re-built by debian.
|
||||
|
||||
#### The Future Distro ####
|
||||
|
||||
Next in the list is Debian 9, code name – Stretch, what it will have is yet to be revealed. The best is yet to come, Just Wait for it!
|
||||
|
||||
A lot of distribution made an appearance in Linux Distro genre and then disappeared. In most cases managing as it gets bigger was a concern. But certainly this is not the case with Debian. It has hundreds of thousands of developer and maintainer all across the globe. It is a one Distro which was there from the initial days of Linux.
|
||||
|
||||
The contribution of Debian in Linux ecosystem can’t be measured in words. If there had been no Debian, Linux would not have been so rich and user-friendly. Debian is among one of the disto which is considered highly reliable, secure and stable and a perfect choice for Web Servers.
|
||||
|
||||
That’s the beginning of Debian. It came a long way and still going. The Future is Here! The world is here! If you have not used Debian till now, What are you Waiting for. Just Download Your Image and get started, we will be here if you get into trouble.
|
||||
|
||||
- [Debian Homepage][2]
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/happy-birthday-to-debian-gnu-linux/
|
||||
|
||||
作者：[Avishek Kumar][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/avishek/
|
||||
[1]:http://xmodulo.com/2013/08/interesting-facts-about-debian-linux.html
|
||||
[2]:https://www.debian.org/
|
||||
@ -0,0 +1,53 @@
|
||||
Docker Working on Security Components, Live Container Migration
|
||||
================================================================================
|
||||
|
||||
|
||||
**Docker developers take the stage at Containercon and discuss their work on future container innovations for security and live migration.**
|
||||
|
||||
SEATTLE—Containers are one of the hottest topics in IT today and at the Linuxcon USA event here there is a co-located event called Containercon, dedicated to this virtualization technology.
|
||||
|
||||
Docker, the lead commercial sponsor of the open-source Docker effort brought three of its top people to the keynote stage today, but not Docker founder Solomon Hykes.
|
||||
|
||||
Hykes who delivered a Linuxcon keynote in 2014 was in the audience though, as Senior Vice President of Engineering Marianna Tessel, Docker security chief Diogo Monica and Docker chief maintainer Michael Crosby presented what's new and what's coming in Docker.
|
||||
|
||||
Tessel emphasized that Docker is very real today and used in production environments at some of the largest organizations on the planet, including the U.S. Government. Docker also is working in small environments too, including the Raspberry Pi small form factor ARM computer, which now can support up to 2,300 containers on a single device.
|
||||
|
||||
"We're getting more powerful and at the same time Docker will also get simpler to use," Tessel said.
|
||||
|
||||
As a metaphor, Tessel said that the whole Docker experience is much like a cruise ship, where there is powerful and complex machinery that powers the ship, yet the experience for passengers is all smooth sailing.
|
||||
|
||||
One area that Docker is trying to make easier is security. Tessel said that security is mind-numbingly complex for most people as organizations constantly try to avoid network breaches.
|
||||
|
||||
That's where Docker Content Trust comes into play, which is a configurable feature in the recent Docker 1.8 release. Diogo Mónica, security lead for Docker joined Tessel on stage and said that security is a hard topic, which is why Docker content trust is being developed.
|
||||
|
||||
With Docker Content Trust there is a verifiable way to make sure that a given Docker application image is authentic. There also are controls to limit fraud and potential malicious code injection by verifying application freshness.
|
||||
|
||||
To prove his point, Monica did a live demonstration of what could happen if Content Trust is not enabled. In one instance, a Website update is manipulated to allow the demo Web app to be defaced. When Content Trust is enabled, the hack didn't work and was blocked.
|
||||
|
||||
"Don't let the simple demo fool you," Tessel said. "You have seen the best security possible."
|
||||
|
||||
One area where containers haven't been put to use before is for live migration, which on VMware virtual machines is a technology called vMotion. It's an area that Docker is currently working on.
|
||||
|
||||
Docker chief maintainer Michael Crosby did an onstage demonstration of a live migration of Docker containers. Crosby referred to the approach as checkpoint and restore, where a running container gets a checkpoint snapshot and is then restored to another location.
|
||||
|
||||
A container also can be cloned and then run in another location. Crosby humorously referred to his cloned container as "Dolly," a reference to the world's first cloned animal, Dolly the sheep.
|
||||
|
||||
Tessel also took time to talk about the RunC component of containers, which is now a technology component that is being developed by the Open Containers Initiative as a multi-stakeholder process. With RunC, containers expand beyond Linux to multiple operating systems including Windows and Solaris.
|
||||
|
||||
Overall, Tessel said that she can't predict the future of Docker, though she is very optimistic.
|
||||
|
||||
"I'm not sure what the future is, but I'm sure it'll be out of this world," Tessel said.
|
||||
|
||||
Sean Michael Kerner is a senior editor at eWEEK and InternetNews.com. Follow him on Twitter @TechJournalist.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.eweek.com/virtualization/docker-working-on-security-components-live-container-migration.html
|
||||
|
||||
作者：[Sean Michael Kerner][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.eweek.com/cp/bio/Sean-Michael-Kerner/
|
||||
@ -1,145 +0,0 @@
|
||||
Vic020
|
||||
|
||||
Linux Tricks: Play Game in Chrome, Text-to-Speech, Schedule a Job and Watch Commands in Linux
|
||||
================================================================================
|
||||
Here again, I have compiled a list of four things under [Linux Tips and Tricks][1] series you may do to remain more productive and entertained with Linux Environment.
|
||||
|
||||
|
||||
|
||||
Linux Tips and Tricks Series
|
||||
|
||||
The topics I have covered includes Google-chrome inbuilt small game, Text-to-speech in Linux Terminal, Quick job scheduling using ‘at‘ command and watch a command at regular interval.
|
||||
|
||||
### 1. Play A Game in Google Chrome Browser ###
|
||||
|
||||
Very often when there is a power shedding or no network due to some other reason, I don’t put my Linux box into maintenance mode. I keep myself engage in a little fun game by Google Chrome. I am not a gamer and hence I have not installed third-party creepy games. Security is another concern.
|
||||
|
||||
So when there is Internet related issue and my web page seems something like this:
|
||||
|
||||
|
||||
|
||||
Unable to Connect Internet
|
||||
|
||||
You may play the Google-chrome inbuilt game simply by hitting the space-bar. There is no limitation for the number of times you can play. The best thing is you need not break a sweat installing and using it.
|
||||
|
||||
No third-party application/plugin required. It should work well on other platforms like Windows and Mac but our niche is Linux and I’ll talk about Linux only and mind it, it works well on Linux. It is a very simple game (a kind of time pass).
|
||||
|
||||
Use Space-Bar/Navigation-up-key to jump. A glimpse of the game in action.
|
||||
|
||||
|
||||
|
||||
Play Game in Google Chrome
|
||||
|
||||
### 2. Text to Speech in Linux Terminal ###
|
||||
|
||||
For those who may not be aware of espeak utility, It is a Linux command-line text to speech converter. Write anything in a variety of languages and espeak utility will read it loud for you.
|
||||
|
||||
Espeak should be installed in your system by default, however it is not installed for your system, you may do:
|
||||
|
||||
# apt-get install espeak (Debian)
|
||||
# yum install espeak (CentOS)
|
||||
# dnf install espeak (Fedora 22 onwards)
|
||||
|
||||
You may ask espeak to accept Input Interactively from standard Input device and convert it to speech for you. You may do:
|
||||
|
||||
$ espeak [Hit Return Key]
|
||||
|
||||
For detailed output you may do:
|
||||
|
||||
$ espeak --stdout | aplay [Hit Return Key][Double - Here]
|
||||
|
||||
espeak is flexible and you can ask espeak to accept input from a text file and speak it loud for you. All you need to do is:
|
||||
|
||||
$ espeak --stdout /path/to/text/file/file_name.txt | aplay [Hit Enter]
|
||||
|
||||
You may ask espeak to speak fast/slow for you. The default speed is 160 words per minute. Define your preference using switch ‘-s’.
|
||||
|
||||
To ask espeak to speak 30 words per minute, you may do:
|
||||
|
||||
$ espeak -s 30 -f /path/to/text/file/file_name.txt | aplay
|
||||
|
||||
To ask espeak to speak 200 words per minute, you may do:
|
||||
|
||||
$ espeak -s 200 -f /path/to/text/file/file_name.txt | aplay
|
||||
|
||||
To use another language say Hindi (my mother tongue), you may do:
|
||||
|
||||
$ espeak -v hindi --stdout 'टेकमिंट विश्व की एक बेहतरीन लाइंक्स आधारित वेबसाइट है|' | aplay
|
||||
|
||||
You may choose any language of your preference and ask to speak in your preferred language as suggested above. To get the list of all the languages supported by espeak, you need to run:
|
||||
|
||||
$ espeak --voices
|
||||
|
||||
### 3. Quick Schedule a Job ###
|
||||
|
||||
Most of us are already familiar with [cron][2] which is a daemon to execute scheduled commands.
|
||||
|
||||
Cron is an advanced command often used by Linux SYSAdmins to schedule a job such as Backup or practically anything at certain time/interval.
|
||||
|
||||
Are you aware of ‘at’ command in Linux which lets you schedule a job/command to run at specific time? You can tell ‘at’ what to do and when to do and everything else will be taken care by command ‘at’.
|
||||
|
||||
For an example, say you want to print the output of uptime command at 11:02 AM, All you need to do is:
|
||||
|
||||
$ at 11:02
|
||||
uptime >> /home/$USER/uptime.txt
|
||||
Ctrl+D
|
||||
|
||||
|
||||
|
||||
Schedule Job in Linux
|
||||
|
||||
To check if the command/script/job has been set or not by ‘at’ command, you may do:
|
||||
|
||||
$ at -l
|
||||
|
||||
|
||||
|
||||
View Scheduled Jobs
|
||||
|
||||
You may schedule more than one command in one go using at, simply as:
|
||||
|
||||
$ at 12:30
|
||||
Command – 1
|
||||
Command – 2
|
||||
…
|
||||
command – 50
|
||||
…
|
||||
Ctrl + D
|
||||
|
||||
### 4. Watch a Command at Specific Interval ###
|
||||
|
||||
We need to run some command for specified amount of time at regular interval. Just for example say we need to print the current time and watch the output every 3 seconds.
|
||||
|
||||
To see current time we need to run the below command in terminal.
|
||||
|
||||
$ date +"%H:%M:%S
|
||||
|
||||
|
||||
|
||||
Check Date and Time in Linux
|
||||
|
||||
and to check the output of this command every three seconds, we need to run the below command in Terminal.
|
||||
|
||||
$ watch -n 3 'date +"%H:%M:%S"'
|
||||
|
||||
|
||||
|
||||
Watch Command in Linux
|
||||
|
||||
The switch ‘-n’ in watch command is for Interval. In the above example we defined Interval to be 3 sec. You may define yours as required. Also you may pass any command/script with watch command to watch that command/script at the defined interval.
|
||||
|
||||
That’s all for now. Hope you are like this series that aims at making you more productive with Linux and that too with fun inside. All the suggestions are welcome in the comments below. Stay tuned for more such posts. Keep connected and Enjoy…
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/text-to-speech-in-terminal-schedule-a-job-and-watch-commands-in-linux/
|
||||
|
||||
作者：[Avishek Kumar][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/avishek/
|
||||
[1]:http://www.tecmint.com/tag/linux-tricks/
|
||||
[2]:http://www.tecmint.com/11-cron-scheduling-task-examples-in-linux/
|
||||
@ -0,0 +1,99 @@
|
||||
How to monitor stock quotes from the command line on Linux
|
||||
================================================================================
|
||||
If you are one of those stock investors or traders, monitoring the stock market will be one of your daily routines. Most likely you will be using an online trading platform which comes with some fancy real-time charts and all sort of advanced stock analysis and tracking tools. While such sophisticated market research tools are a must for any serious stock investors to read the market, monitoring the latest stock quotes still goes a long way to build a profitable portfolio.
|
||||
|
||||
If you are a full-time system admin constantly sitting in front of terminals while trading stocks as a hobby during the day, a simple command-line tool that shows real-time stock quotes will be a blessing for you.
|
||||
|
||||
In this tutorial, let me introduce a neat command-line tool that allows you to monitor stock quotes from the command line on Linux.
|
||||
|
||||
This tool is called [Mop][1]. Written in Go, this lightweight command-line tool is extremely handy for tracking the latest stock quotes from the U.S. markets. You can easily customize the list of stocks to monitor, and it shows the latest stock quotes in ncurses-based, easy-to-read interface.
|
||||
|
||||
**Note**: Mop obtains the latest stock quotes via Yahoo! Finance API. Be aware that their stock quotes are known to be delayed by 15 minutes. So if you are looking for "real-time" stock quotes with zero delay, Mop is not a tool for you. Such "live" stock quote feeds are usually available for a fee via some proprietary closed-door interface. With that being said, let's see how you can use Mop under Linux environment.
|
||||
|
||||
### Install Mop on Linux ###
|
||||
|
||||
Since Mop is implemented in Go, you will need to install Go language first. If you don't have Go installed, follow [this guide][2] to install Go on your Linux platform. Make sure to set GOPATH environment variable as described in the guide.
|
||||
|
||||
Once Go is installed, proceed to install Mop as follows.
|
||||
|
||||
**Debian, Ubuntu or Linux Mint**
|
||||
|
||||
$ sudo apt-get install git
|
||||
$ go get github.com/michaeldv/mop
|
||||
$ cd $GOPATH/src/github.com/michaeldv/mop
|
||||
$ make install
|
||||
|
||||
Fedora, CentOS, RHEL
|
||||
|
||||
$ sudo yum install git
|
||||
$ go get github.com/michaeldv/mop
|
||||
$ cd $GOPATH/src/github.com/michaeldv/mop
|
||||
$ make install
|
||||
|
||||
The above commands will install Mop under $GOPATH/bin.
|
||||
|
||||
Now edit your .bashrc to include $GOPATH/bin in your PATH variable.
|
||||
|
||||
export PATH="$PATH:$GOPATH/bin"
|
||||
|
||||
----------
|
||||
|
||||
$ source ~/.bashrc
|
||||
|
||||
### Monitor Stock Quotes from the Command Line with Mop ###
|
||||
|
||||
To launch Mod, simply run the command called cmd.
|
||||
|
||||
$ cmd
|
||||
|
||||
At the first launch, you will see a few stock tickers which Mop comes pre-configured with.
|
||||
|
||||
|
||||
|
||||
The quotes show information like the latest price, %change, daily low/high, 52-week low/high, dividend, and annual yield. Mop obtains market overview information from [CNN][3], and individual stock quotes from [Yahoo Finance][4]. The stock quote information updates itself within the terminal periodically.
|
||||
|
||||
### Customize Stock Quotes in Mop ###
|
||||
|
||||
Let's try customizing the stock list. Mop provides easy-to-remember shortcuts for this: '+' to add a new stock, and '-' to remove a stock.
|
||||
|
||||
To add a new stock, press '+', and type a stock ticker symbol to add (e.g., MSFT). You can add more than one stock at once by typing a comma-separated list of tickers (e.g., "MSFT, AMZN, TSLA").
|
||||
|
||||
|
||||
|
||||
Removing stocks from the list can be done similarly by pressing '-'.
|
||||
|
||||
### Sort Stock Quotes in Mop ###
|
||||
|
||||
You can sort the stock quote list based on any column. To sort, press 'o', and use left/right key to choose the column to sort by. When a particular column is chosen, you can sort the list either in increasing order or in decreasing order by pressing ENTER.
|
||||
|
||||
|
||||
|
||||
By pressing 'g', you can group your stocks based on whether they are advancing or declining for the day. Advancing issues are represented in green color, while declining issues are colored in white.
|
||||
|
||||
|
||||
|
||||
If you want to access help page, simply press '?'.
|
||||
|
||||
|
||||
|
||||
### Conclusion ###
|
||||
|
||||
As you can see, Mop is a lightweight, yet extremely handy stock monitoring tool. Of course you can easily access stock quotes information elsewhere, from online websites, your smartphone, etc. However, if you spend a great deal of your time in a terminal environment, Mop can easily fit in to your workspace, hopefully without distracting must of your workflow. Just let it run and continuously update market date in one of your terminals, and be done with it.
|
||||
|
||||
Happy trading!
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://xmodulo.com/monitor-stock-quotes-command-line-linux.html
|
||||
|
||||
作者：[Dan Nanni][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://xmodulo.com/author/nanni
|
||||
[1]:https://github.com/michaeldv/mop
|
||||
[2]:http://ask.xmodulo.com/install-go-language-linux.html
|
||||
[3]:http://money.cnn.com/data/markets/
|
||||
[4]:http://finance.yahoo.com/
|
||||
@ -0,0 +1,315 @@
|
||||
Part 10 - LFCS: Understanding & Learning Basic Shell Scripting and Linux Filesystem Troubleshooting
|
||||
================================================================================
|
||||
The Linux Foundation launched the LFCS certification (Linux Foundation Certified Sysadmin), a brand new initiative whose purpose is to allow individuals everywhere (and anywhere) to get certified in basic to intermediate operational support for Linux systems, which includes supporting running systems and services, along with overall monitoring and analysis, plus smart decision-making when it comes to raising issues to upper support teams.
|
||||
|
||||
|
||||
|
||||
Linux Foundation Certified Sysadmin – Part 10
|
||||
|
||||
Check out the following video that guides you an introduction to the Linux Foundation Certification Program.
|
||||
|
||||
注：youtube 视频
|
||||
|
||||
<iframe width="720" height="405" frameborder="0" allowfullscreen="allowfullscreen" src="//www.youtube.com/embed/Y29qZ71Kicg"></iframe>
|
||||
|
||||
This is the last article (Part 10) of the present 10-tutorial long series. In this article we will focus on basic shell scripting and troubleshooting Linux file systems. Both topics are required for the LFCS certification exam.
|
||||
|
||||
### Understanding Terminals and Shells ###
|
||||
|
||||
Let’s clarify a few concepts first.
|
||||
|
||||
- A shell is a program that takes commands and gives them to the operating system to be executed.
|
||||
- A terminal is a program that allows us as end users to interact with the shell. One example of a terminal is GNOME terminal, as shown in the below image.
|
||||
|
||||
|
||||
|
||||
Gnome Terminal
|
||||
|
||||
When we first start a shell, it presents a command prompt (also known as the command line), which tells us that the shell is ready to start accepting commands from its standard input device, which is usually the keyboard.
|
||||
|
||||
You may want to refer to another article in this series ([Use Command to Create, Edit, and Manipulate files – Part 1][1]) to review some useful commands.
|
||||
|
||||
Linux provides a range of options for shells, the following being the most common:
|
||||
|
||||
**bash Shell**
|
||||
|
||||
Bash stands for Bourne Again SHell and is the GNU Project’s default shell. It incorporates useful features from the Korn shell (ksh) and C shell (csh), offering several improvements at the same time. This is the default shell used by the distributions covered in the LFCS certification, and it is the shell that we will use in this tutorial.
|
||||
|
||||
**sh Shell**
|
||||
|
||||
The Bourne SHell is the oldest shell and therefore has been the default shell of many UNIX-like operating systems for many years.
|
||||
ksh Shell
|
||||
|
||||
The Korn SHell is a Unix shell which was developed by David Korn at Bell Labs in the early 1980s. It is backward-compatible with the Bourne shell and includes many features of the C shell.
|
||||
|
||||
A shell script is nothing more and nothing less than a text file turned into an executable program that combines commands that are executed by the shell one after another.
|
||||
|
||||
### Basic Shell Scripting ###
|
||||
|
||||
As mentioned earlier, a shell script is born as a plain text file. Thus, can be created and edited using our preferred text editor. You may want to consider using vi/m (refer to [Usage of vi Editor – Part 2][2] of this series), which features syntax highlighting for your convenience.
|
||||
|
||||
Type the following command to create a file named myscript.sh and press Enter.
|
||||
|
||||
# vim myscript.sh
|
||||
|
||||
The very first line of a shell script must be as follows (also known as a shebang).
|
||||
|
||||
#!/bin/bash
|
||||
|
||||
It “tells” the operating system the name of the interpreter that should be used to run the text that follows.
|
||||
|
||||
Now it’s time to add our commands. We can clarify the purpose of each command, or the entire script, by adding comments as well. Note that the shell ignores those lines beginning with a pound sign # (explanatory comments).
|
||||
|
||||
#!/bin/bash
|
||||
echo This is Part 10 of the 10-article series about the LFCS certification
|
||||
echo Today is $(date +%Y-%m-%d)
|
||||
|
||||
Once the script has been written and saved, we need to make it executable.
|
||||
|
||||
# chmod 755 myscript.sh
|
||||
|
||||
Before running our script, we need to say a few words about the $PATH environment variable. If we run,
|
||||
|
||||
echo $PATH
|
||||
|
||||
from the command line, we will see the contents of $PATH: a colon-separated list of directories that are searched when we enter the name of a executable program. It is called an environment variable because it is part of the shell environment – a set of information that becomes available for the shell and its child processes when the shell is first started.
|
||||
|
||||
When we type a command and press Enter, the shell searches in all the directories listed in the $PATH variable and executes the first instance that is found. Let’s see an example,
|
||||
|
||||
|
||||
|
||||
Environment Variables
|
||||
|
||||
If there are two executable files with the same name, one in /usr/local/bin and another in /usr/bin, the one in the first directory will be executed first, whereas the other will be disregarded.
|
||||
|
||||
If we haven’t saved our script inside one of the directories listed in the $PATH variable, we need to append ./ to the file name in order to execute it. Otherwise, we can run it just as we would do with a regular command.
|
||||
|
||||
# pwd
|
||||
# ./myscript.sh
|
||||
# cp myscript.sh ../bin
|
||||
# cd ../bin
|
||||
# pwd
|
||||
# myscript.sh
|
||||
|
||||
|
||||
|
||||
Execute Script
|
||||
|
||||
#### Conditionals ####
|
||||
|
||||
Whenever you need to specify different courses of action to be taken in a shell script, as result of the success or failure of a command, you will use the if construct to define such conditions. Its basic syntax is:
|
||||
|
||||
if CONDITION; then
|
||||
COMMANDS;
|
||||
else
|
||||
OTHER-COMMANDS
|
||||
fi
|
||||
|
||||
Where CONDITION can be one of the following (only the most frequent conditions are cited here) and evaluates to true when:
|
||||
|
||||
- [ -a file ] → file exists.
|
||||
- [ -d file ] → file exists and is a directory.
|
||||
- [ -f file ] →file exists and is a regular file.
|
||||
- [ -u file ] →file exists and its SUID (set user ID) bit is set.
|
||||
- [ -g file ] →file exists and its SGID bit is set.
|
||||
- [ -k file ] →file exists and its sticky bit is set.
|
||||
- [ -r file ] →file exists and is readable.
|
||||
- [ -s file ]→ file exists and is not empty.
|
||||
- [ -w file ]→file exists and is writable.
|
||||
- [ -x file ] is true if file exists and is executable.
|
||||
- [ string1 = string2 ] → the strings are equal.
|
||||
- [ string1 != string2 ] →the strings are not equal.
|
||||
|
||||
[ int1 op int2 ] should be part of the preceding list, while the items that follow (for example, -eq –> is true if int1 is equal to int2.) should be a “children” list of [ int1 op int2 ] where op is one of the following comparison operators.
|
||||
|
||||
- -eq –> is true if int1 is equal to int2.
|
||||
- -ne –> true if int1 is not equal to int2.
|
||||
- -lt –> true if int1 is less than int2.
|
||||
- -le –> true if int1 is less than or equal to int2.
|
||||
- -gt –> true if int1 is greater than int2.
|
||||
- -ge –> true if int1 is greater than or equal to int2.
|
||||
|
||||
#### For Loops ####
|
||||
|
||||
This loop allows to execute one or more commands for each value in a list of values. Its basic syntax is:
|
||||
|
||||
for item in SEQUENCE; do
|
||||
COMMANDS;
|
||||
done
|
||||
|
||||
Where item is a generic variable that represents each value in SEQUENCE during each iteration.
|
||||
|
||||
#### While Loops ####
|
||||
|
||||
This loop allows to execute a series of repetitive commands as long as the control command executes with an exit status equal to zero (successfully). Its basic syntax is:
|
||||
|
||||
while EVALUATION_COMMAND; do
|
||||
EXECUTE_COMMANDS;
|
||||
done
|
||||
|
||||
Where EVALUATION_COMMAND can be any command(s) that can exit with a success (0) or failure (other than 0) status, and EXECUTE_COMMANDS can be any program, script or shell construct, including other nested loops.
|
||||
|
||||
#### Putting It All Together ####
|
||||
|
||||
We will demonstrate the use of the if construct and the for loop with the following example.
|
||||
|
||||
**Determining if a service is running in a systemd-based distro**
|
||||
|
||||
Let’s create a file with a list of services that we want to monitor at a glance.
|
||||
|
||||
# cat myservices.txt
|
||||
|
||||
sshd
|
||||
mariadb
|
||||
httpd
|
||||
crond
|
||||
firewalld
|
||||
|
||||
|
||||
|
||||
Script to Monitor Linux Services
|
||||
|
||||
Our shell script should look like.
|
||||
|
||||
#!/bin/bash
|
||||
|
||||
# This script iterates over a list of services and
|
||||
# is used to determine whether they are running or not.
|
||||
|
||||
for service in $(cat myservices.txt); do
|
||||
systemctl status $service | grep --quiet "running"
|
||||
if [ $? -eq 0 ]; then
|
||||
echo $service "is [ACTIVE]"
|
||||
else
|
||||
echo $service "is [INACTIVE or NOT INSTALLED]"
|
||||
fi
|
||||
done
|
||||
|
||||
|
||||
|
||||
Linux Service Monitoring Script
|
||||
|
||||
**Let’s explain how the script works.**
|
||||
|
||||
1). The for loop reads the myservices.txt file one element of LIST at a time. That single element is denoted by the generic variable named service. The LIST is populated with the output of,
|
||||
|
||||
# cat myservices.txt
|
||||
|
||||
2). The above command is enclosed in parentheses and preceded by a dollar sign to indicate that it should be evaluated to populate the LIST that we will iterate over.
|
||||
|
||||
3). For each element of LIST (meaning every instance of the service variable), the following command will be executed.
|
||||
|
||||
# systemctl status $service | grep --quiet "running"
|
||||
|
||||
This time we need to precede our generic variable (which represents each element in LIST) with a dollar sign to indicate it’s a variable and thus its value in each iteration should be used. The output is then piped to grep.
|
||||
|
||||
The –quiet flag is used to prevent grep from displaying to the screen the lines where the word running appears. When that happens, the above command returns an exit status of 0 (represented by $? in the if construct), thus verifying that the service is running.
|
||||
|
||||
An exit status different than 0 (meaning the word running was not found in the output of systemctl status $service) indicates that the service is not running.
|
||||
|
||||
|
||||
|
||||
Services Monitoring Script
|
||||
|
||||
We could go one step further and check for the existence of myservices.txt before even attempting to enter the for loop.
|
||||
|
||||
#!/bin/bash
|
||||
|
||||
# This script iterates over a list of services and
|
||||
# is used to determine whether they are running or not.
|
||||
|
||||
if [ -f myservices.txt ]; then
|
||||
for service in $(cat myservices.txt); do
|
||||
systemctl status $service | grep --quiet "running"
|
||||
if [ $? -eq 0 ]; then
|
||||
echo $service "is [ACTIVE]"
|
||||
else
|
||||
echo $service "is [INACTIVE or NOT INSTALLED]"
|
||||
fi
|
||||
done
|
||||
else
|
||||
echo "myservices.txt is missing"
|
||||
fi
|
||||
|
||||
**Pinging a series of network or internet hosts for reply statistics**
|
||||
|
||||
You may want to maintain a list of hosts in a text file and use a script to determine every now and then whether they’re pingable or not (feel free to replace the contents of myhosts and try for yourself).
|
||||
|
||||
The read shell built-in command tells the while loop to read myhosts line by line and assigns the content of each line to variable host, which is then passed to the ping command.
|
||||
|
||||
#!/bin/bash
|
||||
|
||||
# This script is used to demonstrate the use of a while loop
|
||||
|
||||
while read host; do
|
||||
ping -c 2 $host
|
||||
done < myhosts
|
||||
|
||||
|
||||
|
||||
Script to Ping Servers
|
||||
|
||||
Read Also:
|
||||
|
||||
- [Learn Shell Scripting: A Guide from Newbies to System Administrator][3]
|
||||
- [5 Shell Scripts to Learn Shell Programming][4]
|
||||
|
||||
### Filesystem Troubleshooting ###
|
||||
|
||||
Although Linux is a very stable operating system, if it crashes for some reason (for example, due to a power outage), one (or more) of your file systems will not be unmounted properly and thus will be automatically checked for errors when Linux is restarted.
|
||||
|
||||
In addition, each time the system boots during a normal boot, it always checks the integrity of the filesystems before mounting them. In both cases this is performed using a tool named fsck (“file system check”).
|
||||
|
||||
fsck will not only check the integrity of file systems, but also attempt to repair corrupt file systems if instructed to do so. Depending on the severity of damage, fsck may succeed or not; when it does, recovered portions of files are placed in the lost+found directory, located in the root of each file system.
|
||||
|
||||
Last but not least, we must note that inconsistencies may also happen if we try to remove an USB drive when the operating system is still writing to it, and may even result in hardware damage.
|
||||
|
||||
The basic syntax of fsck is as follows:
|
||||
|
||||
# fsck [options] filesystem
|
||||
|
||||
**Checking a filesystem for errors and attempting to repair automatically**
|
||||
|
||||
In order to check a filesystem with fsck, we must first unmount it.
|
||||
|
||||
# mount | grep sdg1
|
||||
# umount /mnt
|
||||
# fsck -y /dev/sdg1
|
||||
|
||||
|
||||
|
||||
Check Filesystem Errors
|
||||
|
||||
Besides the -y flag, we can use the -a option to automatically repair the file systems without asking any questions, and force the check even when the filesystem looks clean.
|
||||
|
||||
# fsck -af /dev/sdg1
|
||||
|
||||
If we’re only interested in finding out what’s wrong (without trying to fix anything for the time being) we can run fsck with the -n option, which will output the filesystem issues to standard output.
|
||||
|
||||
# fsck -n /dev/sdg1
|
||||
|
||||
Depending on the error messages in the output of fsck, we will know whether we can try to solve the issue ourselves or escalate it to engineering teams to perform further checks on the hardware.
|
||||
|
||||
### Summary ###
|
||||
|
||||
We have arrived at the end of this 10-article series where have tried to cover the basic domain competencies required to pass the LFCS exam.
|
||||
|
||||
For obvious reasons, it is not possible to cover every single aspect of these topics in any single tutorial, and that’s why we hope that these articles have put you on the right track to try new stuff yourself and continue learning.
|
||||
|
||||
If you have any questions or comments, they are always welcome – so don’t hesitate to drop us a line via the form below!
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/linux-basic-shell-scripting-and-linux-filesystem-troubleshooting/
|
||||
|
||||
作者：[Gabriel Cánepa][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/gacanepa/
|
||||
[1]:http://www.tecmint.com/sed-command-to-create-edit-and-manipulate-files-in-linux/
|
||||
[2]:http://www.tecmint.com/vi-editor-usage/
|
||||
[3]:http://www.tecmint.com/learning-shell-scripting-language-a-guide-from-newbies-to-system-administrator/
|
||||
[4]:http://www.tecmint.com/basic-shell-programming-part-ii/
|
||||
@ -0,0 +1,276 @@
|
||||
Part 6 - LFCS: Assembling Partitions as RAID Devices – Creating & Managing System Backups
|
||||
================================================================================
|
||||
Recently, the Linux Foundation launched the LFCS (Linux Foundation Certified Sysadmin) certification, a shiny chance for system administrators everywhere to demonstrate, through a performance-based exam, that they are capable of performing overall operational support on Linux systems: system support, first-level diagnosing and monitoring, plus issue escalation, when required, to other support teams.
|
||||
|
||||
|
||||
|
||||
Linux Foundation Certified Sysadmin – Part 6
|
||||
|
||||
The following video provides an introduction to The Linux Foundation Certification Program.
|
||||
|
||||
注：youtube 视频
|
||||
<iframe width="720" height="405" frameborder="0" allowfullscreen="allowfullscreen" src="//www.youtube.com/embed/Y29qZ71Kicg"></iframe>
|
||||
|
||||
This post is Part 6 of a 10-tutorial series, here in this part, we will explain How to Assemble Partitions as RAID Devices – Creating & Managing System Backups, that are required for the LFCS certification exam.
|
||||
|
||||
### Understanding RAID ###
|
||||
|
||||
The technology known as Redundant Array of Independent Disks (RAID) is a storage solution that combines multiple hard disks into a single logical unit to provide redundancy of data and/or improve performance in read / write operations to disk.
|
||||
|
||||
However, the actual fault-tolerance and disk I/O performance lean on how the hard disks are set up to form the disk array. Depending on the available devices and the fault tolerance / performance needs, different RAID levels are defined. You can refer to the RAID series here in Tecmint.com for a more detailed explanation on each RAID level.
|
||||
|
||||
- RAID Guide: [What is RAID, Concepts of RAID and RAID Levels Explained][1]
|
||||
|
||||
Our tool of choice for creating, assembling, managing, and monitoring our software RAIDs is called mdadm (short for multiple disks admin).
|
||||
|
||||
---------------- Debian and Derivatives ----------------
|
||||
# aptitude update && aptitude install mdadm
|
||||
|
||||
----------
|
||||
|
||||
---------------- Red Hat and CentOS based Systems ----------------
|
||||
# yum update && yum install mdadm
|
||||
|
||||
----------
|
||||
|
||||
---------------- On openSUSE ----------------
|
||||
# zypper refresh && zypper install mdadm #
|
||||
|
||||
#### Assembling Partitions as RAID Devices ####
|
||||
|
||||
The process of assembling existing partitions as RAID devices consists of the following steps.
|
||||
|
||||
**1. Create the array using mdadm**
|
||||
|
||||
If one of the partitions has been formatted previously, or has been a part of another RAID array previously, you will be prompted to confirm the creation of the new array. Assuming you have taken the necessary precautions to avoid losing important data that may have resided in them, you can safely type y and press Enter.
|
||||
|
||||
# mdadm --create --verbose /dev/md0 --level=stripe --raid-devices=2 /dev/sdb1 /dev/sdc1
|
||||
|
||||
|
||||
|
||||
Creating RAID Array
|
||||
|
||||
**2. Check the array creation status**
|
||||
|
||||
After creating RAID array, you an check the status of the array using the following commands.
|
||||
|
||||
# cat /proc/mdstat
|
||||
or
|
||||
# mdadm --detail /dev/md0 [More detailed summary]
|
||||
|
||||
|
||||
|
||||
Check RAID Array Status
|
||||
|
||||
**3. Format the RAID Device**
|
||||
|
||||
Format the device with a filesystem as per your needs / requirements, as explained in [Part 4][2] of this series.
|
||||
|
||||
**4. Monitor RAID Array Service**
|
||||
|
||||
Instruct the monitoring service to “keep an eye” on the array. Add the output of mdadm –detail –scan to /etc/mdadm/mdadm.conf (Debian and derivatives) or /etc/mdadm.conf (CentOS / openSUSE), like so.
|
||||
|
||||
# mdadm --detail --scan
|
||||
|
||||
|
||||
|
||||
Monitor RAID Array
|
||||
|
||||
# mdadm --assemble --scan [Assemble the array]
|
||||
|
||||
To ensure the service starts on system boot, run the following commands as root.
|
||||
|
||||
**Debian and Derivatives**
|
||||
|
||||
Debian and derivatives, though it should start running on boot by default.
|
||||
|
||||
# update-rc.d mdadm defaults
|
||||
|
||||
Edit the /etc/default/mdadm file and add the following line.
|
||||
|
||||
AUTOSTART=true
|
||||
|
||||
**On CentOS and openSUSE (systemd-based)**
|
||||
|
||||
# systemctl start mdmonitor
|
||||
# systemctl enable mdmonitor
|
||||
|
||||
**On CentOS and openSUSE (SysVinit-based)**
|
||||
|
||||
# service mdmonitor start
|
||||
# chkconfig mdmonitor on
|
||||
|
||||
**5. Check RAID Disk Failure**
|
||||
|
||||
In RAID levels that support redundancy, replace failed drives when needed. When a device in the disk array becomes faulty, a rebuild automatically starts only if there was a spare device added when we first created the array.
|
||||
|
||||
|
||||
|
||||
Check RAID Faulty Disk
|
||||
|
||||
Otherwise, we need to manually attach an extra physical drive to our system and run.
|
||||
|
||||
# mdadm /dev/md0 --add /dev/sdX1
|
||||
|
||||
Where /dev/md0 is the array that experienced the issue and /dev/sdX1 is the new device.
|
||||
|
||||
**6. Disassemble a working array**
|
||||
|
||||
You may have to do this if you need to create a new array using the devices – (Optional Step).
|
||||
|
||||
# mdadm --stop /dev/md0 # Stop the array
|
||||
# mdadm --remove /dev/md0 # Remove the RAID device
|
||||
# mdadm --zero-superblock /dev/sdX1 # Overwrite the existing md superblock with zeroes
|
||||
|
||||
**7. Set up mail alerts**
|
||||
|
||||
You can configure a valid email address or system account to send alerts to (make sure you have this line in mdadm.conf). – (Optional Step)
|
||||
|
||||
MAILADDR root
|
||||
|
||||
In this case, all alerts that the RAID monitoring daemon collects will be sent to the local root account’s mail box. One of such alerts looks like the following.
|
||||
|
||||
**Note**: This event is related to the example in STEP 5, where a device was marked as faulty and the spare device was automatically built into the array by mdadm. Thus, we “ran out” of healthy spare devices and we got the alert.
|
||||
|
||||
|
||||
|
||||
RAID Monitoring Alerts
|
||||
|
||||
#### Understanding RAID Levels ####
|
||||
|
||||
**RAID 0**
|
||||
|
||||
The total array size is n times the size of the smallest partition, where n is the number of independent disks in the array (you will need at least two drives). Run the following command to assemble a RAID 0 array using partitions /dev/sdb1 and /dev/sdc1.
|
||||
|
||||
# mdadm --create --verbose /dev/md0 --level=stripe --raid-devices=2 /dev/sdb1 /dev/sdc1
|
||||
|
||||
Common uses: Setups that support real-time applications where performance is more important than fault-tolerance.
|
||||
|
||||
**RAID 1 (aka Mirroring)**
|
||||
|
||||
The total array size equals the size of the smallest partition (you will need at least two drives). Run the following command to assemble a RAID 1 array using partitions /dev/sdb1 and /dev/sdc1.
|
||||
|
||||
# mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/sdb1 /dev/sdc1
|
||||
|
||||
Common uses: Installation of the operating system or important subdirectories, such as /home.
|
||||
|
||||
**RAID 5 (aka drives with Parity)**
|
||||
|
||||
The total array size will be (n – 1) times the size of the smallest partition. The “lost” space in (n-1) is used for parity (redundancy) calculation (you will need at least three drives).
|
||||
|
||||
Note that you can specify a spare device (/dev/sde1 in this case) to replace a faulty part when an issue occurs. Run the following command to assemble a RAID 5 array using partitions /dev/sdb1, /dev/sdc1, /dev/sdd1, and /dev/sde1 as spare.
|
||||
|
||||
# mdadm --create --verbose /dev/md0 --level=5 --raid-devices=3 /dev/sdb1 /dev/sdc1 /dev/sdd1 --spare-devices=1 /dev/sde1
|
||||
|
||||
Common uses: Web and file servers.
|
||||
|
||||
**RAID 6 (aka drives with double Parity**
|
||||
|
||||
The total array size will be (n*s)-2*s, where n is the number of independent disks in the array and s is the size of the smallest disk. Note that you can specify a spare device (/dev/sdf1 in this case) to replace a faulty part when an issue occurs.
|
||||
|
||||
Run the following command to assemble a RAID 6 array using partitions /dev/sdb1, /dev/sdc1, /dev/sdd1, /dev/sde1, and /dev/sdf1 as spare.
|
||||
|
||||
# mdadm --create --verbose /dev/md0 --level=6 --raid-devices=4 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde --spare-devices=1 /dev/sdf1
|
||||
|
||||
Common uses: File and backup servers with large capacity and high availability requirements.
|
||||
|
||||
**RAID 1+0 (aka stripe of mirrors)**
|
||||
|
||||
The total array size is computed based on the formulas for RAID 0 and RAID 1, since RAID 1+0 is a combination of both. First, calculate the size of each mirror and then the size of the stripe.
|
||||
|
||||
Note that you can specify a spare device (/dev/sdf1 in this case) to replace a faulty part when an issue occurs. Run the following command to assemble a RAID 1+0 array using partitions /dev/sdb1, /dev/sdc1, /dev/sdd1, /dev/sde1, and /dev/sdf1 as spare.
|
||||
|
||||
# mdadm --create --verbose /dev/md0 --level=10 --raid-devices=4 /dev/sd[b-e]1 --spare-devices=1 /dev/sdf1
|
||||
|
||||
Common uses: Database and application servers that require fast I/O operations.
|
||||
|
||||
#### Creating and Managing System Backups ####
|
||||
|
||||
It never hurts to remember that RAID with all its bounties IS NOT A REPLACEMENT FOR BACKUPS! Write it 1000 times on the chalkboard if you need to, but make sure you keep that idea in mind at all times. Before we begin, we must note that there is no one-size-fits-all solution for system backups, but here are some things that you do need to take into account while planning a backup strategy.
|
||||
|
||||
- What do you use your system for? (Desktop or server? If the latter case applies, what are the most critical services – whose configuration would be a real pain to lose?)
|
||||
- How often do you need to take backups of your system?
|
||||
- What is the data (e.g. files / directories / database dumps) that you want to backup? You may also want to consider if you really need to backup huge files (such as audio or video files).
|
||||
- Where (meaning physical place and media) will those backups be stored?
|
||||
|
||||
**Backing Up Your Data**
|
||||
|
||||
Method 1: Backup entire drives with dd command. You can either back up an entire hard disk or a partition by creating an exact image at any point in time. Note that this works best when the device is offline, meaning it’s not mounted and there are no processes accessing it for I/O operations.
|
||||
|
||||
The downside of this backup approach is that the image will have the same size as the disk or partition, even when the actual data occupies a small percentage of it. For example, if you want to image a partition of 20 GB that is only 10% full, the image file will still be 20 GB in size. In other words, it’s not only the actual data that gets backed up, but the entire partition itself. You may consider using this method if you need exact backups of your devices.
|
||||
|
||||
**Creating an image file out of an existing device**
|
||||
|
||||
# dd if=/dev/sda of=/system_images/sda.img
|
||||
OR
|
||||
--------------------- Alternatively, you can compress the image file ---------------------
|
||||
# dd if=/dev/sda | gzip -c > /system_images/sda.img.gz
|
||||
|
||||
**Restoring the backup from the image file**
|
||||
|
||||
# dd if=/system_images/sda.img of=/dev/sda
|
||||
OR
|
||||
|
||||
--------------------- Depending on your choice while creating the image ---------------------
|
||||
gzip -dc /system_images/sda.img.gz | dd of=/dev/sda
|
||||
|
||||
Method 2: Backup certain files / directories with tar command – already covered in [Part 3][3] of this series. You may consider using this method if you need to keep copies of specific files and directories (configuration files, users’ home directories, and so on).
|
||||
|
||||
Method 3: Synchronize files with rsync command. Rsync is a versatile remote (and local) file-copying tool. If you need to backup and synchronize your files to/from network drives, rsync is a go.
|
||||
|
||||
Whether you’re synchronizing two local directories or local < — > remote directories mounted on the local filesystem, the basic syntax is the same.
|
||||
Synchronizing two local directories or local < — > remote directories mounted on the local filesystem
|
||||
|
||||
# rsync -av source_directory destination directory
|
||||
|
||||
Where, -a recurse into subdirectories (if they exist), preserve symbolic links, timestamps, permissions, and original owner / group and -v verbose.
|
||||
|
||||
|
||||
|
||||
rsync Synchronizing Files
|
||||
|
||||
In addition, if you want to increase the security of the data transfer over the wire, you can use ssh over rsync.
|
||||
|
||||
**Synchronizing local → remote directories over ssh**
|
||||
|
||||
# rsync -avzhe ssh backups root@remote_host:/remote_directory/
|
||||
|
||||
This example will synchronize the backups directory on the local host with the contents of /root/remote_directory on the remote host.
|
||||
|
||||
Where the -h option shows file sizes in human-readable format, and the -e flag is used to indicate a ssh connection.
|
||||
|
||||
|
||||
|
||||
rsync Synchronize Remote Files
|
||||
|
||||
Synchronizing remote → local directories over ssh.
|
||||
|
||||
In this case, switch the source and destination directories from the previous example.
|
||||
|
||||
# rsync -avzhe ssh root@remote_host:/remote_directory/ backups
|
||||
|
||||
Please note that these are only 3 examples (most frequent cases you’re likely to run into) of the use of rsync. For more examples and usages of rsync commands can be found at the following article.
|
||||
|
||||
- Read Also: [10 rsync Commands to Sync Files in Linux][4]
|
||||
|
||||
### Summary ###
|
||||
|
||||
As a sysadmin, you need to ensure that your systems perform as good as possible. If you’re well prepared, and if the integrity of your data is well supported by a storage technology such as RAID and regular system backups, you’ll be safe.
|
||||
|
||||
If you have questions, comments, or further ideas on how this article can be improved, feel free to speak out below. In addition, please consider sharing this series through your social network profiles.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/creating-and-managing-raid-backups-in-linux/
|
||||
|
||||
作者：[Gabriel Cánepa][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/gacanepa/
|
||||
[1]:http://www.tecmint.com/understanding-raid-setup-in-linux/
|
||||
[2]:http://www.tecmint.com/create-partitions-and-filesystems-in-linux/
|
||||
[3]:http://www.tecmint.com/compress-files-and-finding-files-in-linux/
|
||||
[4]:http://www.tecmint.com/rsync-local-remote-file-synchronization-commands/
|
||||
@ -0,0 +1,367 @@
|
||||
Part 7 - LFCS: Managing System Startup Process and Services (SysVinit, Systemd and Upstart)
|
||||
================================================================================
|
||||
A couple of months ago, the Linux Foundation announced the LFCS (Linux Foundation Certified Sysadmin) certification, an exciting new program whose aim is allowing individuals from all ends of the world to get certified in performing basic to intermediate system administration tasks on Linux systems. This includes supporting already running systems and services, along with first-hand problem-finding and analysis, plus the ability to decide when to raise issues to engineering teams.
|
||||
|
||||
|
||||
|
||||
Linux Foundation Certified Sysadmin – Part 7
|
||||
|
||||
The following video describes an brief introduction to The Linux Foundation Certification Program.
|
||||
|
||||
注：youtube 视频
|
||||
<iframe width="720" height="405" frameborder="0" allowfullscreen="allowfullscreen" src="//www.youtube.com/embed/Y29qZ71Kicg"></iframe>
|
||||
|
||||
This post is Part 7 of a 10-tutorial series, here in this part, we will explain how to Manage Linux System Startup Process and Services, that are required for the LFCS certification exam.
|
||||
|
||||
### Managing the Linux Startup Process ###
|
||||
|
||||
The boot process of a Linux system consists of several phases, each represented by a different component. The following diagram briefly summarizes the boot process and shows all the main components involved.
|
||||
|
||||
|
||||
|
||||
Linux Boot Process
|
||||
|
||||
When you press the Power button on your machine, the firmware that is stored in a EEPROM chip in the motherboard initializes the POST (Power-On Self Test) to check on the state of the system’s hardware resources. When the POST is finished, the firmware then searches and loads the 1st stage boot loader, located in the MBR or in the EFI partition of the first available disk, and gives control to it.
|
||||
|
||||
#### MBR Method ####
|
||||
|
||||
The MBR is located in the first sector of the disk marked as bootable in the BIOS settings and is 512 bytes in size.
|
||||
|
||||
- First 446 bytes: The bootloader contains both executable code and error message text.
|
||||
- Next 64 bytes: The Partition table contains a record for each of four partitions (primary or extended). Among other things, each record indicates the status (active / not active), size, and start / end sectors of each partition.
|
||||
- Last 2 bytes: The magic number serves as a validation check of the MBR.
|
||||
|
||||
The following command performs a backup of the MBR (in this example, /dev/sda is the first hard disk). The resulting file, mbr.bkp can come in handy should the partition table become corrupt, for example, rendering the system unbootable.
|
||||
|
||||
Of course, in order to use it later if the need arises, we will need to save it and store it somewhere else (like a USB drive, for example). That file will help us restore the MBR and will get us going once again if and only if we do not change the hard drive layout in the meanwhile.
|
||||
|
||||
**Backup MBR**
|
||||
|
||||
# dd if=/dev/sda of=mbr.bkp bs=512 count=1
|
||||
|
||||
|
||||
|
||||
Backup MBR in Linux
|
||||
|
||||
**Restoring MBR**
|
||||
|
||||
# dd if=mbr.bkp of=/dev/sda bs=512 count=1
|
||||
|
||||
|
||||
|
||||
Restore MBR in Linux
|
||||
|
||||
#### EFI/UEFI Method ####
|
||||
|
||||
For systems using the EFI/UEFI method, the UEFI firmware reads its settings to determine which UEFI application is to be launched and from where (i.e., in which disk and partition the EFI partition is located).
|
||||
|
||||
Next, the 2nd stage boot loader (aka boot manager) is loaded and run. GRUB [GRand Unified Boot] is the most frequently used boot manager in Linux. One of two distinct versions can be found on most systems used today.
|
||||
|
||||
- GRUB legacy configuration file: /boot/grub/menu.lst (older distributions, not supported by EFI/UEFI firmwares).
|
||||
- GRUB2 configuration file: most likely, /etc/default/grub.
|
||||
|
||||
Although the objectives of the LFCS exam do not explicitly request knowledge about GRUB internals, if you’re brave and can afford to mess up your system (you may want to try it first on a virtual machine, just in case), you need to run.
|
||||
|
||||
# update-grub
|
||||
|
||||
As root after modifying GRUB’s configuration in order to apply the changes.
|
||||
|
||||
Basically, GRUB loads the default kernel and the initrd or initramfs image. In few words, initrd or initramfs help to perform the hardware detection, the kernel module loading and the device discovery necessary to get the real root filesystem mounted.
|
||||
|
||||
Once the real root filesystem is up, the kernel executes the system and service manager (init or systemd, whose process identification or PID is always 1) to begin the normal user-space boot process in order to present a user interface.
|
||||
|
||||
Both init and systemd are daemons (background processes) that manage other daemons, as the first service to start (during boot) and the last service to terminate (during shutdown).
|
||||
|
||||
|
||||
|
||||
Systemd and Init
|
||||
|
||||
### Starting Services (SysVinit) ###
|
||||
|
||||
The concept of runlevels in Linux specifies different ways to use a system by controlling which services are running. In other words, a runlevel controls what tasks can be accomplished in the current execution state = runlevel (and which ones cannot).
|
||||
|
||||
Traditionally, this startup process was performed based on conventions that originated with System V UNIX, with the system passing executing collections of scripts that start and stop services as the machine entered a specific runlevel (which, in other words, is a different mode of running the system).
|
||||
|
||||
Within each runlevel, individual services can be set to run, or to be shut down if running. Latest versions of some major distributions are moving away from the System V standard in favour of a rather new service and system manager called systemd (which stands for system daemon), but usually support sysv commands for compatibility purposes. This means that you can run most of the well-known sysv init tools in a systemd-based distribution.
|
||||
|
||||
- Read Also: [Why ‘systemd’ replaces ‘init’ in Linux][1]
|
||||
|
||||
Besides starting the system process, init looks to the /etc/inittab file to decide what runlevel must be entered.
|
||||
|
||||
注：表格
|
||||
<table cellspacing="0" border="0">
|
||||
<colgroup width="85">
|
||||
</colgroup>
|
||||
<colgroup width="1514">
|
||||
</colgroup>
|
||||
<tbody>
|
||||
<tr>
|
||||
<td align="CENTER" height="18" style="border: 1px solid #000001;"><b>Runlevel</b></td>
|
||||
<td align="LEFT" style="border: 1px solid #000001;"><b> Description</b></td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="CENTER" height="18" style="border: 1px solid #000001;">0</td>
|
||||
<td align="LEFT" style="border: 1px solid #000001;"> Halt the system. Runlevel 0 is a special transitional state used to shutdown the system quickly.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="CENTER" height="20" style="border: 1px solid #000001;">1</td>
|
||||
<td align="LEFT" style="border: 1px solid #000001;"> Also aliased to s, or S, this runlevel is sometimes called maintenance mode. What services, if any, are started at this runlevel varies by distribution. It’s typically used for low-level system maintenance that may be impaired by normal system operation.</td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="CENTER" height="18" style="border: 1px solid #000001;">2</td>
|
||||
<td align="LEFT" style="border: 1px solid #000001;"> Multiuser. On Debian systems and derivatives, this is the default runlevel, and includes -if available- a graphical login. On Red-Hat based systems, this is multiuser mode without networking.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="CENTER" height="18" style="border: 1px solid #000001;">3</td>
|
||||
<td align="LEFT" style="border: 1px solid #000001;"> On Red-Hat based systems, this is the default multiuser mode, which runs everything except the graphical environment. This runlevel and levels 4 and 5 usually are not used on Debian-based systems.</td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="CENTER" height="18" style="border: 1px solid #000001;">4</td>
|
||||
<td align="LEFT" style="border: 1px solid #000001;"> Typically unused by default and therefore available for customization.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="CENTER" height="18" style="border: 1px solid #000001;">5</td>
|
||||
<td align="LEFT" style="border: 1px solid #000001;"> On Red-Hat based systems, full multiuser mode with GUI login. This runlevel is like level 3, but with a GUI login available.</td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="CENTER" height="18" style="border: 1px solid #000001;">6</td>
|
||||
<td align="LEFT" style="border: 1px solid #000001;"> Reboot the system.</td>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
|
||||
To switch between runlevels, we can simply issue a runlevel change using the init command: init N (where N is one of the runlevels listed above). Please note that this is not the recommended way of taking a running system to a different runlevel because it gives no warning to existing logged-in users (thus causing them to lose work and processes to terminate abnormally).
|
||||
|
||||
Instead, the shutdown command should be used to restart the system (which first sends a warning message to all logged-in users and blocks any further logins; it then signals init to switch runlevels); however, the default runlevel (the one the system will boot to) must be edited in the /etc/inittab file first.
|
||||
|
||||
For that reason, follow these steps to properly switch between runlevels, As root, look for the following line in /etc/inittab.
|
||||
|
||||
id:2:initdefault:
|
||||
|
||||
and change the number 2 for the desired runlevel with your preferred text editor, such as vim (described in [How to use vi/vim editor in Linux – Part 2][2] of this series).
|
||||
|
||||
Next, run as root.
|
||||
|
||||
# shutdown -r now
|
||||
|
||||
That last command will restart the system, causing it to start in the specified runlevel during next boot, and will run the scripts located in the /etc/rc[runlevel].d directory in order to decide which services should be started and which ones should not. For example, for runlevel 2 in the following system.
|
||||
|
||||
|
||||
|
||||
Change Runlevels in Linux
|
||||
|
||||
#### Manage Services using chkconfig ####
|
||||
|
||||
To enable or disable system services on boot, we will use [chkconfig command][3] in CentOS / openSUSE and sysv-rc-conf in Debian and derivatives. This tool can also show us what is the preconfigured state of a service for a particular runlevel.
|
||||
|
||||
- Read Also: [How to Stop and Disable Unwanted Services in Linux][4]
|
||||
|
||||
Listing the runlevel configuration for a service.
|
||||
|
||||
# chkconfig --list [service name]
|
||||
# chkconfig --list postfix
|
||||
# chkconfig --list mysqld
|
||||
|
||||
|
||||
|
||||
Listing Runlevel Configuration
|
||||
|
||||
In the above image we can see that postfix is set to start when the system enters runlevels 2 through 5, whereas mysqld will be running by default for runlevels 2 through 4. Now suppose that this is not the expected behaviour.
|
||||
|
||||
For example, we need to turn on mysqld for runlevel 5 as well, and turn off postfix for runlevels 4 and 5. Here’s what we would do in each case (run the following commands as root).
|
||||
|
||||
**Enabling a service for a particular runlevel**
|
||||
|
||||
# chkconfig --level [level(s)] service on
|
||||
# chkconfig --level 5 mysqld on
|
||||
|
||||
**Disabling a service for particular runlevels**
|
||||
|
||||
# chkconfig --level [level(s)] service off
|
||||
# chkconfig --level 45 postfix off
|
||||
|
||||
|
||||
|
||||
Enable Disable Services
|
||||
|
||||
We will now perform similar tasks in a Debian-based system using sysv-rc-conf.
|
||||
|
||||
#### Manage Services using sysv-rc-conf ####
|
||||
|
||||
Configuring a service to start automatically on a specific runlevel and prevent it from starting on all others.
|
||||
|
||||
1. Let’s use the following command to see what are the runlevels where mdadm is configured to start.
|
||||
|
||||
# ls -l /etc/rc[0-6].d | grep -E 'rc[0-6]|mdadm'
|
||||
|
||||
|
||||
|
||||
Check Runlevel of Service Running
|
||||
|
||||
2. We will use sysv-rc-conf to prevent mdadm from starting on all runlevels except 2. Just check or uncheck (with the space bar) as desired (you can move up, down, left, and right with the arrow keys).
|
||||
|
||||
# sysv-rc-conf
|
||||
|
||||
|
||||
|
||||
SysV Runlevel Config
|
||||
|
||||
Then press q to quit.
|
||||
|
||||
3. We will restart the system and run again the command from STEP 1.
|
||||
|
||||
# ls -l /etc/rc[0-6].d | grep -E 'rc[0-6]|mdadm'
|
||||
|
||||
|
||||
|
||||
Verify Service Runlevel
|
||||
|
||||
In the above image we can see that mdadm is configured to start only on runlevel 2.
|
||||
|
||||
### What About systemd? ###
|
||||
|
||||
systemd is another service and system manager that is being adopted by several major Linux distributions. It aims to allow more processing to be done in parallel during system startup (unlike sysvinit, which always tends to be slower because it starts processes one at a time, checks whether one depends on another, and waits for daemons to launch so more services can start), and to serve as a dynamic resource management to a running system.
|
||||
|
||||
Thus, services are started when needed (to avoid consuming system resources) instead of being launched without a solid reason during boot.
|
||||
|
||||
Viewing the status of all the processes running on your system, both systemd native and SysV services, run the following command.
|
||||
|
||||
# systemctl
|
||||
|
||||
|
||||
|
||||
Check All Running Processes
|
||||
|
||||
The LOAD column shows whether the unit definition (refer to the UNIT column, which shows the service or anything maintained by systemd) was properly loaded, while the ACTIVE and SUB columns show the current status of such unit.
|
||||
Displaying information about the current status of a service
|
||||
|
||||
When the ACTIVE column indicates that an unit’s status is other than active, we can check what happened using.
|
||||
|
||||
# systemctl status [unit]
|
||||
|
||||
For example, in the image above, media-samba.mount is in failed state. Let’s run.
|
||||
|
||||
# systemctl status media-samba.mount
|
||||
|
||||
|
||||
|
||||
Check Service Status
|
||||
|
||||
We can see that media-samba.mount failed because the mount process on host dev1 was unable to find the network share at //192.168.0.10/gacanepa.
|
||||
|
||||
### Starting or Stopping Services ###
|
||||
|
||||
Once the network share //192.168.0.10/gacanepa becomes available, let’s try to start, then stop, and finally restart the unit media-samba.mount. After performing each action, let’s run systemctl status media-samba.mount to check on its status.
|
||||
|
||||
# systemctl start media-samba.mount
|
||||
# systemctl status media-samba.mount
|
||||
# systemctl stop media-samba.mount
|
||||
# systemctl restart media-samba.mount
|
||||
# systemctl status media-samba.mount
|
||||
|
||||
|
||||
|
||||
Starting Stoping Services
|
||||
|
||||
**Enabling or disabling a service to start during boot**
|
||||
|
||||
Under systemd you can enable or disable a service when it boots.
|
||||
|
||||
# systemctl enable [service] # enable a service
|
||||
# systemctl disable [service] # prevent a service from starting at boot
|
||||
|
||||
The process of enabling or disabling a service to start automatically on boot consists in adding or removing symbolic links in the /etc/systemd/system/multi-user.target.wants directory.
|
||||
|
||||
|
||||
|
||||
Enabling Disabling Services
|
||||
|
||||
Alternatively, you can find out a service’s current status (enabled or disabled) with the command.
|
||||
|
||||
# systemctl is-enabled [service]
|
||||
|
||||
For example,
|
||||
|
||||
# systemctl is-enabled postfix.service
|
||||
|
||||
In addition, you can reboot or shutdown the system with.
|
||||
|
||||
# systemctl reboot
|
||||
# systemctl shutdown
|
||||
|
||||
### Upstart ###
|
||||
|
||||
Upstart is an event-based replacement for the /sbin/init daemon and was born out of the need for starting services only, when they are needed (also supervising them while they are running), and handling events as they occur, thus surpassing the classic, dependency-based sysvinit system.
|
||||
|
||||
It was originally developed for the Ubuntu distribution, but is used in Red Hat Enterprise Linux 6.0. Though it was intended to be suitable for deployment in all Linux distributions as a replacement for sysvinit, in time it was overshadowed by systemd. On February 14, 2014, Mark Shuttleworth (founder of Canonical Ltd.) announced that future releases of Ubuntu would use systemd as the default init daemon.
|
||||
|
||||
Because the SysV startup script for system has been so common for so long, a large number of software packages include SysV startup scripts. To accommodate such packages, Upstart provides a compatibility mode: It runs SysV startup scripts in the usual locations (/etc/rc.d/rc?.d, /etc/init.d/rc?.d, /etc/rc?.d, or a similar location). Thus, if we install a package that doesn’t yet include an Upstart configuration script, it should still launch in the usual way.
|
||||
|
||||
Furthermore, if we have installed utilities such as [chkconfig][5], you should be able to use them to manage your SysV-based services just as we would on sysvinit based systems.
|
||||
|
||||
Upstart scripts also support starting or stopping services based on a wider variety of actions than do SysV startup scripts; for example, Upstart can launch a service whenever a particular hardware device is attached.
|
||||
|
||||
A system that uses Upstart and its native scripts exclusively replaces the /etc/inittab file and the runlevel-specific SysV startup script directories with .conf scripts in the /etc/init directory.
|
||||
|
||||
These *.conf scripts (also known as job definitions) generally consists of the following:
|
||||
|
||||
- Description of the process.
|
||||
- Runlevels where the process should run or events that should trigger it.
|
||||
- Runlevels where process should be stopped or events that should stop it.
|
||||
- Options.
|
||||
- Command to launch the process.
|
||||
|
||||
For example,
|
||||
|
||||
# My test service - Upstart script demo description "Here goes the description of 'My test service'" author "Dave Null <dave.null@example.com>"
|
||||
# Stanzas
|
||||
|
||||
#
|
||||
# Stanzas define when and how a process is started and stopped
|
||||
# See a list of stanzas here: http://upstart.ubuntu.com/wiki/Stanzas#respawn
|
||||
# When to start the service
|
||||
start on runlevel [2345]
|
||||
# When to stop the service
|
||||
stop on runlevel [016]
|
||||
# Automatically restart process in case of crash
|
||||
respawn
|
||||
# Specify working directory
|
||||
chdir /home/dave/myfiles
|
||||
# Specify the process/command (add arguments if needed) to run
|
||||
exec bash backup.sh arg1 arg2
|
||||
|
||||
To apply changes, you will need to tell upstart to reload its configuration.
|
||||
|
||||
# initctl reload-configuration
|
||||
|
||||
Then start your job by typing the following command.
|
||||
|
||||
$ sudo start yourjobname
|
||||
|
||||
Where yourjobname is the name of the job that was added earlier with the yourjobname.conf script.
|
||||
|
||||
A more complete and detailed reference guide for Upstart is available in the project’s web site under the menu “[Cookbook][6]”.
|
||||
|
||||
### Summary ###
|
||||
|
||||
A knowledge of the Linux boot process is necessary to help you with troubleshooting tasks as well as with adapting the computer’s performance and running services to your needs.
|
||||
|
||||
In this article we have analyzed what happens from the moment when you press the Power switch to turn on the machine until you get a fully operational user interface. I hope you have learned reading it as much as I did while putting it together. Feel free to leave your comments or questions below. We always look forward to hearing from our readers!
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/linux-boot-process-and-manage-services/
|
||||
|
||||
作者：[Gabriel Cánepa][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/gacanepa/
|
||||
[1]:http://www.tecmint.com/systemd-replaces-init-in-linux/
|
||||
[2]:http://www.tecmint.com/vi-editor-usage/
|
||||
[3]:http://www.tecmint.com/chkconfig-command-examples/
|
||||
[4]:http://www.tecmint.com/remove-unwanted-services-from-linux/
|
||||
[5]:http://www.tecmint.com/chkconfig-command-examples/
|
||||
[6]:http://upstart.ubuntu.com/cookbook/
|
||||
@ -0,0 +1,330 @@
|
||||
Part 8 - LFCS: Managing Users & Groups, File Permissions & Attributes and Enabling sudo Access on Accounts
|
||||
================================================================================
|
||||
Last August, the Linux Foundation started the LFCS certification (Linux Foundation Certified Sysadmin), a brand new program whose purpose is to allow individuals everywhere and anywhere take an exam in order to get certified in basic to intermediate operational support for Linux systems, which includes supporting running systems and services, along with overall monitoring and analysis, plus intelligent decision-making to be able to decide when it’s necessary to escalate issues to higher level support teams.
|
||||
|
||||
|
||||
|
||||
Linux Foundation Certified Sysadmin – Part 8
|
||||
|
||||
Please have a quick look at the following video that describes an introduction to the Linux Foundation Certification Program.
|
||||
|
||||
注：youtube视频
|
||||
<iframe width="720" height="405" frameborder="0" allowfullscreen="allowfullscreen" src="//www.youtube.com/embed/Y29qZ71Kicg"></iframe>
|
||||
|
||||
This article is Part 8 of a 10-tutorial long series, here in this section, we will guide you on how to manage users and groups permissions in Linux system, that are required for the LFCS certification exam.
|
||||
|
||||
Since Linux is a multi-user operating system (in that it allows multiple users on different computers or terminals to access a single system), you will need to know how to perform effective user management: how to add, edit, suspend, or delete user accounts, along with granting them the necessary permissions to do their assigned tasks.
|
||||
|
||||
### Adding User Accounts ###
|
||||
|
||||
To add a new user account, you can run either of the following two commands as root.
|
||||
|
||||
# adduser [new_account]
|
||||
# useradd [new_account]
|
||||
|
||||
When a new user account is added to the system, the following operations are performed.
|
||||
|
||||
1. His/her home directory is created (/home/username by default).
|
||||
|
||||
2. The following hidden files are copied into the user’s home directory, and will be used to provide environment variables for his/her user session.
|
||||
|
||||
.bash_logout
|
||||
.bash_profile
|
||||
.bashrc
|
||||
|
||||
3. A mail spool is created for the user at /var/spool/mail/username.
|
||||
|
||||
4. A group is created and given the same name as the new user account.
|
||||
|
||||
**Understanding /etc/passwd**
|
||||
|
||||
The full account information is stored in the /etc/passwd file. This file contains a record per system user account and has the following format (fields are delimited by a colon).
|
||||
|
||||
[username]:[x]:[UID]:[GID]:[Comment]:[Home directory]:[Default shell]
|
||||
|
||||
- Fields [username] and [Comment] are self explanatory.
|
||||
- The x in the second field indicates that the account is protected by a shadowed password (in /etc/shadow), which is needed to logon as [username].
|
||||
- The [UID] and [GID] fields are integers that represent the User IDentification and the primary Group IDentification to which [username] belongs, respectively.
|
||||
- The [Home directory] indicates the absolute path to [username]’s home directory, and
|
||||
- The [Default shell] is the shell that will be made available to this user when he or she logins the system.
|
||||
|
||||
**Understanding /etc/group**
|
||||
|
||||
Group information is stored in the /etc/group file. Each record has the following format.
|
||||
|
||||
[Group name]:[Group password]:[GID]:[Group members]
|
||||
|
||||
- [Group name] is the name of group.
|
||||
- An x in [Group password] indicates group passwords are not being used.
|
||||
- [GID]: same as in /etc/passwd.
|
||||
- [Group members]: a comma separated list of users who are members of [Group name].
|
||||
|
||||
|
||||
|
||||
Add User Accounts
|
||||
|
||||
After adding an account, you can edit the following information (to name a few fields) using the usermod command, whose basic syntax of usermod is as follows.
|
||||
|
||||
# usermod [options] [username]
|
||||
|
||||
**Setting the expiry date for an account**
|
||||
|
||||
Use the –expiredate flag followed by a date in YYYY-MM-DD format.
|
||||
|
||||
# usermod --expiredate 2014-10-30 tecmint
|
||||
|
||||
**Adding the user to supplementary groups**
|
||||
|
||||
Use the combined -aG, or –append –groups options, followed by a comma separated list of groups.
|
||||
|
||||
# usermod --append --groups root,users tecmint
|
||||
|
||||
**Changing the default location of the user’s home directory**
|
||||
|
||||
Use the -d, or –home options, followed by the absolute path to the new home directory.
|
||||
|
||||
# usermod --home /tmp tecmint
|
||||
|
||||
**Changing the shell the user will use by default**
|
||||
|
||||
Use –shell, followed by the path to the new shell.
|
||||
|
||||
# usermod --shell /bin/sh tecmint
|
||||
|
||||
**Displaying the groups an user is a member of**
|
||||
|
||||
# groups tecmint
|
||||
# id tecmint
|
||||
|
||||
Now let’s execute all the above commands in one go.
|
||||
|
||||
# usermod --expiredate 2014-10-30 --append --groups root,users --home /tmp --shell /bin/sh tecmint
|
||||
|
||||
|
||||
|
||||
usermod Command Examples
|
||||
|
||||
Read Also:
|
||||
|
||||
- [15 useradd Command Examples in Linux][1]
|
||||
- [15 usermod Command Examples in Linux][2]
|
||||
|
||||
For existing accounts, we can also do the following.
|
||||
|
||||
**Disabling account by locking password**
|
||||
|
||||
Use the -L (uppercase L) or the –lock option to lock a user’s password.
|
||||
|
||||
# usermod --lock tecmint
|
||||
|
||||
**Unlocking user password**
|
||||
|
||||
Use the –u or the –unlock option to unlock a user’s password that was previously blocked.
|
||||
|
||||
# usermod --unlock tecmint
|
||||
|
||||
|
||||
|
||||
Lock User Accounts
|
||||
|
||||
**Creating a new group for read and write access to files that need to be accessed by several users**
|
||||
|
||||
Run the following series of commands to achieve the goal.
|
||||
|
||||
# groupadd common_group # Add a new group
|
||||
# chown :common_group common.txt # Change the group owner of common.txt to common_group
|
||||
# usermod -aG common_group user1 # Add user1 to common_group
|
||||
# usermod -aG common_group user2 # Add user2 to common_group
|
||||
# usermod -aG common_group user3 # Add user3 to common_group
|
||||
|
||||
**Deleting a group**
|
||||
|
||||
You can delete a group with the following command.
|
||||
|
||||
# groupdel [group_name]
|
||||
|
||||
If there are files owned by group_name, they will not be deleted, but the group owner will be set to the GID of the group that was deleted.
|
||||
|
||||
### Linux File Permissions ###
|
||||
|
||||
Besides the basic read, write, and execute permissions that we discussed in [Setting File Attributes – Part 3][3] of this series, there are other less used (but not less important) permission settings, sometimes referred to as “special permissions”.
|
||||
|
||||
Like the basic permissions discussed earlier, they are set using an octal file or through a letter (symbolic notation) that indicates the type of permission.
|
||||
Deleting user accounts
|
||||
|
||||
You can delete an account (along with its home directory, if it’s owned by the user, and all the files residing therein, and also the mail spool) using the userdel command with the –remove option.
|
||||
|
||||
# userdel --remove [username]
|
||||
|
||||
#### Group Management ####
|
||||
|
||||
Every time a new user account is added to the system, a group with the same name is created with the username as its only member. Other users can be added to the group later. One of the purposes of groups is to implement a simple access control to files and other system resources by setting the right permissions on those resources.
|
||||
|
||||
For example, suppose you have the following users.
|
||||
|
||||
- user1 (primary group: user1)
|
||||
- user2 (primary group: user2)
|
||||
- user3 (primary group: user3)
|
||||
|
||||
All of them need read and write access to a file called common.txt located somewhere on your local system, or maybe on a network share that user1 has created. You may be tempted to do something like,
|
||||
|
||||
# chmod 660 common.txt
|
||||
OR
|
||||
# chmod u=rw,g=rw,o= common.txt [notice the space between the last equal sign and the file name]
|
||||
|
||||
However, this will only provide read and write access to the owner of the file and to those users who are members of the group owner of the file (user1 in this case). Again, you may be tempted to add user2 and user3 to group user1, but that will also give them access to the rest of the files owned by user user1 and group user1.
|
||||
|
||||
This is where groups come in handy, and here’s what you should do in a case like this.
|
||||
|
||||
**Understanding Setuid**
|
||||
|
||||
When the setuid permission is applied to an executable file, an user running the program inherits the effective privileges of the program’s owner. Since this approach can reasonably raise security concerns, the number of files with setuid permission must be kept to a minimum. You will likely find programs with this permission set when a system user needs to access a file owned by root.
|
||||
|
||||
Summing up, it isn’t just that the user can execute the binary file, but also that he can do so with root’s privileges. For example, let’s check the permissions of /bin/passwd. This binary is used to change the password of an account, and modifies the /etc/shadow file. The superuser can change anyone’s password, but all other users should only be able to change their own.
|
||||
|
||||
|
||||
|
||||
passwd Command Examples
|
||||
|
||||
Thus, any user should have permission to run /bin/passwd, but only root will be able to specify an account. Other users can only change their corresponding passwords.
|
||||
|
||||
|
||||
|
||||
Change User Password
|
||||
|
||||
**Understanding Setgid**
|
||||
|
||||
When the setgid bit is set, the effective GID of the real user becomes that of the group owner. Thus, any user can access a file under the privileges granted to the group owner of such file. In addition, when the setgid bit is set on a directory, newly created files inherit the same group as the directory, and newly created subdirectories will also inherit the setgid bit of the parent directory. You will most likely use this approach whenever members of a certain group need access to all the files in a directory, regardless of the file owner’s primary group.
|
||||
|
||||
# chmod g+s [filename]
|
||||
|
||||
To set the setgid in octal form, prepend the number 2 to the current (or desired) basic permissions.
|
||||
|
||||
# chmod 2755 [directory]
|
||||
|
||||
**Setting the SETGID in a directory**
|
||||
|
||||
|
||||
|
||||
Add Setgid to Directory
|
||||
|
||||
**Understanding Sticky Bit**
|
||||
|
||||
When the “sticky bit” is set on files, Linux just ignores it, whereas for directories it has the effect of preventing users from deleting or even renaming the files it contains unless the user owns the directory, the file, or is root.
|
||||
|
||||
# chmod o+t [directory]
|
||||
|
||||
To set the sticky bit in octal form, prepend the number 1 to the current (or desired) basic permissions.
|
||||
|
||||
# chmod 1755 [directory]
|
||||
|
||||
Without the sticky bit, anyone able to write to the directory can delete or rename files. For that reason, the sticky bit is commonly found on directories, such as /tmp, that are world-writable.
|
||||
|
||||
|
||||
|
||||
Add Stickybit to Directory
|
||||
|
||||
### Special Linux File Attributes ###
|
||||
|
||||
There are other attributes that enable further limits on the operations that are allowed on files. For example, prevent the file from being renamed, moved, deleted, or even modified. They are set with the [chattr command][4] and can be viewed using the lsattr tool, as follows.
|
||||
|
||||
# chattr +i file1
|
||||
# chattr +a file2
|
||||
|
||||
After executing those two commands, file1 will be immutable (which means it cannot be moved, renamed, modified or deleted) whereas file2 will enter append-only mode (can only be open in append mode for writing).
|
||||
|
||||
|
||||
|
||||
Chattr Command to Protect Files
|
||||
|
||||
### Accessing the root Account and Using sudo ###
|
||||
|
||||
One of the ways users can gain access to the root account is by typing.
|
||||
|
||||
$ su
|
||||
|
||||
and then entering root’s password.
|
||||
|
||||
If authentication succeeds, you will be logged on as root with the current working directory as the same as you were before. If you want to be placed in root’s home directory instead, run.
|
||||
|
||||
$ su -
|
||||
|
||||
and then enter root’s password.
|
||||
|
||||
|
||||
|
||||
Enable Sudo Access on Users
|
||||
|
||||
The above procedure requires that a normal user knows root’s password, which poses a serious security risk. For that reason, the sysadmin can configure the sudo command to allow an ordinary user to execute commands as a different user (usually the superuser) in a very controlled and limited way. Thus, restrictions can be set on a user so as to enable him to run one or more specific privileged commands and no others.
|
||||
|
||||
- Read Also: [Difference Between su and sudo User][5]
|
||||
|
||||
To authenticate using sudo, the user uses his/her own password. After entering the command, we will be prompted for our password (not the superuser’s) and if the authentication succeeds (and if the user has been granted privileges to run the command), the specified command is carried out.
|
||||
|
||||
To grant access to sudo, the system administrator must edit the /etc/sudoers file. It is recommended that this file is edited using the visudo command instead of opening it directly with a text editor.
|
||||
|
||||
# visudo
|
||||
|
||||
This opens the /etc/sudoers file using vim (you can follow the instructions given in [Install and Use vim as Editor – Part 2][6] of this series to edit the file).
|
||||
|
||||
These are the most relevant lines.
|
||||
|
||||
Defaults secure_path="/usr/sbin:/usr/bin:/sbin"
|
||||
root ALL=(ALL) ALL
|
||||
tecmint ALL=/bin/yum update
|
||||
gacanepa ALL=NOPASSWD:/bin/updatedb
|
||||
%admin ALL=(ALL) ALL
|
||||
|
||||
Let’s take a closer look at them.
|
||||
|
||||
Defaults secure_path="/usr/sbin:/usr/bin:/sbin:/usr/local/bin"
|
||||
|
||||
This line lets you specify the directories that will be used for sudo, and is used to prevent using user-specific directories, which can harm the system.
|
||||
|
||||
The next lines are used to specify permissions.
|
||||
|
||||
root ALL=(ALL) ALL
|
||||
|
||||
- The first ALL keyword indicates that this rule applies to all hosts.
|
||||
- The second ALL indicates that the user in the first column can run commands with the privileges of any user.
|
||||
- The third ALL means any command can be run.
|
||||
|
||||
tecmint ALL=/bin/yum update
|
||||
|
||||
If no user is specified after the = sign, sudo assumes the root user. In this case, user tecmint will be able to run yum update as root.
|
||||
|
||||
gacanepa ALL=NOPASSWD:/bin/updatedb
|
||||
|
||||
The NOPASSWD directive allows user gacanepa to run /bin/updatedb without needing to enter his password.
|
||||
|
||||
%admin ALL=(ALL) ALL
|
||||
|
||||
The % sign indicates that this line applies to a group called “admin”. The meaning of the rest of the line is identical to that of an regular user. This means that members of the group “admin” can run all commands as any user on all hosts.
|
||||
|
||||
To see what privileges are granted to you by sudo, use the “-l” option to list them.
|
||||
|
||||
|
||||
|
||||
Sudo Access Rules
|
||||
|
||||
### Summary ###
|
||||
|
||||
Effective user and file management skills are essential tools for any system administrator. In this article we have covered the basics and hope you can use it as a good starting to point to build upon. Feel free to leave your comments or questions below, and we’ll respond quickly.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/manage-users-and-groups-in-linux/
|
||||
|
||||
作者：[Gabriel Cánepa][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/gacanepa/
|
||||
[1]:http://www.tecmint.com/add-users-in-linux/
|
||||
[2]:http://www.tecmint.com/usermod-command-examples/
|
||||
[3]:http://www.tecmint.com/compress-files-and-finding-files-in-linux/
|
||||
[4]:http://www.tecmint.com/chattr-command-examples/
|
||||
[5]:http://www.tecmint.com/su-vs-sudo-and-how-to-configure-sudo-in-linux/
|
||||
[6]:http://www.tecmint.com/vi-editor-usage/
|
||||
@ -0,0 +1,229 @@
|
||||
Part 9 - LFCS: Linux Package Management with Yum, RPM, Apt, Dpkg, Aptitude and Zypper
|
||||
================================================================================
|
||||
Last August, the Linux Foundation announced the LFCS certification (Linux Foundation Certified Sysadmin), a shiny chance for system administrators everywhere to demonstrate, through a performance-based exam, that they are capable of succeeding at overall operational support for Linux systems. A Linux Foundation Certified Sysadmin has the expertise to ensure effective system support, first-level troubleshooting and monitoring, including finally issue escalation, when needed, to engineering support teams.
|
||||
|
||||
|
||||
|
||||
Linux Foundation Certified Sysadmin – Part 9
|
||||
|
||||
Watch the following video that explains about the Linux Foundation Certification Program.
|
||||
|
||||
注：youtube 视频
|
||||
<iframe width="720" height="405" frameborder="0" allowfullscreen="allowfullscreen" src="//www.youtube.com/embed/Y29qZ71Kicg"></iframe>
|
||||
|
||||
This article is a Part 9 of 10-tutorial long series, today in this article we will guide you about Linux Package Management, that are required for the LFCS certification exam.
|
||||
|
||||
### Package Management ###
|
||||
|
||||
In few words, package management is a method of installing and maintaining (which includes updating and probably removing as well) software on the system.
|
||||
|
||||
In the early days of Linux, programs were only distributed as source code, along with the required man pages, the necessary configuration files, and more. Nowadays, most Linux distributors use by default pre-built programs or sets of programs called packages, which are presented to users ready for installation on that distribution. However, one of the wonders of Linux is still the possibility to obtain source code of a program to be studied, improved, and compiled.
|
||||
|
||||
**How package management systems work**
|
||||
|
||||
If a certain package requires a certain resource such as a shared library, or another package, it is said to have a dependency. All modern package management systems provide some method of dependency resolution to ensure that when a package is installed, all of its dependencies are installed as well.
|
||||
|
||||
**Packaging Systems**
|
||||
|
||||
Almost all the software that is installed on a modern Linux system will be found on the Internet. It can either be provided by the distribution vendor through central repositories (which can contain several thousands of packages, each of which has been specifically built, tested, and maintained for the distribution) or be available in source code that can be downloaded and installed manually.
|
||||
|
||||
Because different distribution families use different packaging systems (Debian: *.deb / CentOS: *.rpm / openSUSE: *.rpm built specially for openSUSE), a package intended for one distribution will not be compatible with another distribution. However, most distributions are likely to fall into one of the three distribution families covered by the LFCS certification.
|
||||
|
||||
**High and low-level package tools**
|
||||
|
||||
In order to perform the task of package management effectively, you need to be aware that you will have two types of available utilities: low-level tools (which handle in the backend the actual installation, upgrade, and removal of package files), and high-level tools (which are in charge of ensuring that the tasks of dependency resolution and metadata searching -”data about the data”- are performed).
|
||||
|
||||
注：表格
|
||||
|
||||
<table cellspacing="0" border="0">
|
||||
<colgroup width="200">
|
||||
</colgroup>
|
||||
<colgroup width="200">
|
||||
</colgroup>
|
||||
<colgroup width="200">
|
||||
</colgroup>
|
||||
<tbody>
|
||||
<tr>
|
||||
<td bgcolor="#AEA79F" align="CENTER" height="18" style="border: 1px solid #000001;"><b><span style="color: black;">DISTRIBUTION</span></b></td>
|
||||
<td bgcolor="#AEA79F" align="CENTER" style="border: 1px solid #000001;"><b><span style="color: black;">LOW-LEVEL TOOL</span></b></td>
|
||||
<td bgcolor="#AEA79F" align="CENTER" style="border: 1px solid #000001;"><b><span style="color: black;">HIGH-LEVEL TOOL</span></b></td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td bgcolor="#FFFFFF" align="LEFT" height="18" style="border: 1px solid #000001;"><span style="color: black;"> Debian and derivatives</span></td>
|
||||
<td bgcolor="#FFFFFF" align="LEFT" style="border: 1px solid #000001;"><span style="color: black;"> dpkg</span></td>
|
||||
<td bgcolor="#FFFFFF" align="LEFT" style="border: 1px solid #000001;"><span style="color: black;"> apt-get / aptitude</span></td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td bgcolor="#FFFFFF" align="LEFT" height="18" style="border: 1px solid #000001;"><span style="color: black;"> CentOS</span></td>
|
||||
<td bgcolor="#FFFFFF" align="LEFT" style="border: 1px solid #000001;"><span style="color: black;"> rpm</span></td>
|
||||
<td bgcolor="#FFFFFF" align="LEFT" style="border: 1px solid #000001;"><span style="color: black;"> yum</span></td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td bgcolor="#FFFFFF" align="LEFT" height="18" style="border: 1px solid #000001;"><span style="color: black;"> openSUSE</span></td>
|
||||
<td bgcolor="#FFFFFF" align="LEFT" style="border: 1px solid #000001;"><span style="color: black;"> rpm</span></td>
|
||||
<td bgcolor="#FFFFFF" align="LEFT" style="border: 1px solid #000001;"><span style="color: black;"> zypper</span></td>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
|
||||
Let us see the descrption of the low-level and high-level tools.
|
||||
|
||||
dpkg is a low-level package manager for Debian-based systems. It can install, remove, provide information about and build *.deb packages but it can’t automatically download and install their corresponding dependencies.
|
||||
|
||||
- Read More: [15 dpkg Command Examples][1]
|
||||
|
||||
apt-get is a high-level package manager for Debian and derivatives, and provides a simple way to retrieve and install packages, including dependency resolution, from multiple sources using the command line. Unlike dpkg, apt-get does not work directly with *.deb files, but with the package proper name.
|
||||
|
||||
- Read More: [25 apt-get Command Examples][2]
|
||||
|
||||
aptitude is another high-level package manager for Debian-based systems, and can be used to perform management tasks (installing, upgrading, and removing packages, also handling dependency resolution automatically) in a fast and easy way. It provides the same functionality as apt-get and additional ones, such as offering access to several versions of a package.
|
||||
|
||||
rpm is the package management system used by Linux Standard Base (LSB)-compliant distributions for low-level handling of packages. Just like dpkg, it can query, install, verify, upgrade, and remove packages, and is more frequently used by Fedora-based distributions, such as RHEL and CentOS.
|
||||
|
||||
- Read More: [20 rpm Command Examples][3]
|
||||
|
||||
yum adds the functionality of automatic updates and package management with dependency management to RPM-based systems. As a high-level tool, like apt-get or aptitude, yum works with repositories.
|
||||
|
||||
- Read More: [20 yum Command Examples][4]
|
||||
-
|
||||
### Common Usage of Low-Level Tools ###
|
||||
|
||||
The most frequent tasks that you will do with low level tools are as follows:
|
||||
|
||||
**1. Installing a package from a compiled (*.deb or *.rpm) file**
|
||||
|
||||
The downside of this installation method is that no dependency resolution is provided. You will most likely choose to install a package from a compiled file when such package is not available in the distribution’s repositories and therefore cannot be downloaded and installed through a high-level tool. Since low-level tools do not perform dependency resolution, they will exit with an error if we try to install a package with unmet dependencies.
|
||||
|
||||
# dpkg -i file.deb [Debian and derivative]
|
||||
# rpm -i file.rpm [CentOS / openSUSE]
|
||||
|
||||
**Note**: Do not attempt to install on CentOS a *.rpm file that was built for openSUSE, or vice-versa!
|
||||
|
||||
**2. Upgrading a package from a compiled file**
|
||||
|
||||
Again, you will only upgrade an installed package manually when it is not available in the central repositories.
|
||||
|
||||
# dpkg -i file.deb [Debian and derivative]
|
||||
# rpm -U file.rpm [CentOS / openSUSE]
|
||||
|
||||
**3. Listing installed packages**
|
||||
|
||||
When you first get your hands on an already working system, chances are you’ll want to know what packages are installed.
|
||||
|
||||
# dpkg -l [Debian and derivative]
|
||||
# rpm -qa [CentOS / openSUSE]
|
||||
|
||||
If you want to know whether a specific package is installed, you can pipe the output of the above commands to grep, as explained in [manipulate files in Linux – Part 1][6] of this series. Suppose we need to verify if package mysql-common is installed on an Ubuntu system.
|
||||
|
||||
# dpkg -l | grep mysql-common
|
||||
|
||||
|
||||
|
||||
Check Installed Packages
|
||||
|
||||
Another way to determine if a package is installed.
|
||||
|
||||
# dpkg --status package_name [Debian and derivative]
|
||||
# rpm -q package_name [CentOS / openSUSE]
|
||||
|
||||
For example, let’s find out whether package sysdig is installed on our system.
|
||||
|
||||
# rpm -qa | grep sysdig
|
||||
|
||||
|
||||
|
||||
Check sysdig Package
|
||||
|
||||
**4. Finding out which package installed a file**
|
||||
|
||||
# dpkg --search file_name
|
||||
# rpm -qf file_name
|
||||
|
||||
For example, which package installed pw_dict.hwm?
|
||||
|
||||
# rpm -qf /usr/share/cracklib/pw_dict.hwm
|
||||
|
||||
|
||||
|
||||
Query File in Linux
|
||||
|
||||
### Common Usage of High-Level Tools ###
|
||||
|
||||
The most frequent tasks that you will do with high level tools are as follows.
|
||||
|
||||
**1. Searching for a package**
|
||||
|
||||
aptitude update will update the list of available packages, and aptitude search will perform the actual search for package_name.
|
||||
|
||||
# aptitude update && aptitude search package_name
|
||||
|
||||
In the search all option, yum will search for package_name not only in package names, but also in package descriptions.
|
||||
|
||||
# yum search package_name
|
||||
# yum search all package_name
|
||||
# yum whatprovides “*/package_name”
|
||||
|
||||
Let’s supposed we need a file whose name is sysdig. To know that package we will have to install, let’s run.
|
||||
|
||||
# yum whatprovides “*/sysdig”
|
||||
|
||||
|
||||
|
||||
Check Package Description
|
||||
|
||||
whatprovides tells yum to search the package the will provide a file that matches the above regular expression.
|
||||
|
||||
# zypper refresh && zypper search package_name [On openSUSE]
|
||||
|
||||
**2. Installing a package from a repository**
|
||||
|
||||
While installing a package, you may be prompted to confirm the installation after the package manager has resolved all dependencies. Note that running update or refresh (according to the package manager being used) is not strictly necessary, but keeping installed packages up to date is a good sysadmin practice for security and dependency reasons.
|
||||
|
||||
# aptitude update && aptitude install package_name [Debian and derivatives]
|
||||
# yum update && yum install package_name [CentOS]
|
||||
# zypper refresh && zypper install package_name [openSUSE]
|
||||
|
||||
**3. Removing a package**
|
||||
|
||||
The option remove will uninstall the package but leaving configuration files intact, whereas purge will erase every trace of the program from your system.
|
||||
# aptitude remove / purge package_name
|
||||
# yum erase package_name
|
||||
|
||||
---Notice the minus sign in front of the package that will be uninstalled, openSUSE ---
|
||||
|
||||
# zypper remove -package_name
|
||||
|
||||
Most (if not all) package managers will prompt you, by default, if you’re sure about proceeding with the uninstallation before actually performing it. So read the onscreen messages carefully to avoid running into unnecessary trouble!
|
||||
|
||||
**4. Displaying information about a package**
|
||||
|
||||
The following command will display information about the birthday package.
|
||||
|
||||
# aptitude show birthday
|
||||
# yum info birthday
|
||||
# zypper info birthday
|
||||
|
||||
|
||||
|
||||
Check Package Information
|
||||
|
||||
### Summary ###
|
||||
|
||||
Package management is something you just can’t sweep under the rug as a system administrator. You should be prepared to use the tools described in this article at a moment’s notice. Hope you find it useful in your preparation for the LFCS exam and for your daily tasks. Feel free to leave your comments or questions below. We will be more than glad to get back to you as soon as possible.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/linux-package-management/
|
||||
|
||||
作者：[Gabriel Cánepa][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/gacanepa/
|
||||
[1]:http://www.tecmint.com/dpkg-command-examples/
|
||||
[2]:http://www.tecmint.com/useful-basic-commands-of-apt-get-and-apt-cache-for-package-management/
|
||||
[3]:http://www.tecmint.com/20-practical-examples-of-rpm-commands-in-linux/
|
||||
[4]:http://www.tecmint.com/20-linux-yum-yellowdog-updater-modified-commands-for-package-mangement/
|
||||
[5]:http://www.tecmint.com/sed-command-to-create-edit-and-manipulate-files-in-linux/
|
||||
@ -1,271 +0,0 @@
|
||||
FSSlc translating
|
||||
|
||||
RHCSA Series: Using ‘Parted’ and ‘SSM’ to Configure and Encrypt System Storage – Part 6
|
||||
================================================================================
|
||||
In this article we will discuss how to set up and configure local system storage in Red Hat Enterprise Linux 7 using classic tools and introducing the System Storage Manager (also known as SSM), which greatly simplifies this task.
|
||||
|
||||
|
||||
|
||||
RHCSA: Configure and Encrypt System Storage – Part 6
|
||||
|
||||
Please note that we will present this topic in this article but will continue its description and usage on the next one (Part 7) due to vastness of the subject.
|
||||
|
||||
### Creating and Modifying Partitions in RHEL 7 ###
|
||||
|
||||
In RHEL 7, parted is the default utility to work with partitions, and will allow you to:
|
||||
|
||||
- Display the current partition table
|
||||
- Manipulate (increase or decrease the size of) existing partitions
|
||||
- Create partitions using free space or additional physical storage devices
|
||||
|
||||
It is recommended that before attempting the creation of a new partition or the modification of an existing one, you should ensure that none of the partitions on the device are in use (`umount /dev/partition`), and if you’re using part of the device as swap you need to disable it (`swapoff -v /dev/partition`) during the process.
|
||||
|
||||
The easiest way to do this is to boot RHEL in rescue mode using an installation media such as a RHEL 7 installation DVD or USB (Troubleshooting → Rescue a Red Hat Enterprise Linux system) and Select Skip when you’re prompted to choose an option to mount the existing Linux installation, and you will be presented with a command prompt where you can start typing the same commands as shown as follows during the creation of an ordinary partition in a physical device that is not being used.
|
||||
|
||||
|
||||
|
||||
RHEL 7 Rescue Mode
|
||||
|
||||
To start parted, simply type.
|
||||
|
||||
# parted /dev/sdb
|
||||
|
||||
Where `/dev/sdb` is the device where you will create the new partition; next, type print to display the current drive’s partition table:
|
||||
|
||||
|
||||
|
||||
Creat New Partition
|
||||
|
||||
As you can see, in this example we are using a virtual drive of 5 GB. We will now proceed to create a 4 GB primary partition and then format it with the xfs filesystem, which is the default in RHEL 7.
|
||||
|
||||
You can choose from a variety of file systems. You will need to manually create the partition with mkpart and then format it with mkfs.fstype as usual because mkpart does not support many modern filesystems out-of-the-box.
|
||||
|
||||
In the following example we will set a label for the device and then create a primary partition `(p)` on `/dev/sdb`, which starts at the 0% percentage of the device and ends at 4000 MB (4 GB):
|
||||
|
||||
|
||||
|
||||
Label Partition Name
|
||||
|
||||
Next, we will format the partition as xfs and print the partition table again to verify that changes were applied:
|
||||
|
||||
# mkfs.xfs /dev/sdb1
|
||||
# parted /dev/sdb print
|
||||
|
||||
|
||||
|
||||
Format Partition as XFS Filesystem
|
||||
|
||||
For older filesystems, you could use the resize command in parted to resize a partition. Unfortunately, this only applies to ext2, fat16, fat32, hfs, linux-swap, and reiserfs (if libreiserfs is installed).
|
||||
|
||||
Thus, the only way to resize a partition is by deleting it and creating it again (so make sure you have a good backup of your data!). No wonder the default partitioning scheme in RHEL 7 is based on LVM.
|
||||
|
||||
To remove a partition with parted:
|
||||
|
||||
# parted /dev/sdb print
|
||||
# parted /dev/sdb rm 1
|
||||
|
||||
|
||||
|
||||
Remove or Delete Partition
|
||||
|
||||
### The Logical Volume Manager (LVM) ###
|
||||
|
||||
Once a disk has been partitioned, it can be difficult or risky to change the partition sizes. For that reason, if we plan on resizing the partitions on our system, we should consider the possibility of using LVM instead of the classic partitioning system, where several physical devices can form a volume group that will host a defined number of logical volumes, which can be expanded or reduced without any hassle.
|
||||
|
||||
In simple terms, you may find the following diagram useful to remember the basic architecture of LVM.
|
||||
|
||||
|
||||
|
||||
Basic Architecture of LVM
|
||||
|
||||
#### Creating Physical Volumes, Volume Group and Logical Volumes ####
|
||||
|
||||
Follow these steps in order to set up LVM using classic volume management tools. Since you can expand this topic reading the [LVM series on this site][1], I will only outline the basic steps to set up LVM, and then compare them to implementing the same functionality with SSM.
|
||||
|
||||
**Note**: That we will use the whole disks `/dev/sdb` and `/dev/sdc` as PVs (Physical Volumes) but it’s entirely up to you if you want to do the same.
|
||||
|
||||
**1. Create partitions `/dev/sdb1` and `/dev/sdc1` using 100% of the available disk space in /dev/sdb and /dev/sdc:**
|
||||
|
||||
# parted /dev/sdb print
|
||||
# parted /dev/sdc print
|
||||
|
||||
|
||||
|
||||
Create New Partitions
|
||||
|
||||
**2. Create 2 physical volumes on top of /dev/sdb1 and /dev/sdc1, respectively.**
|
||||
|
||||
# pvcreate /dev/sdb1
|
||||
# pvcreate /dev/sdc1
|
||||
|
||||
|
||||
|
||||
Create Two Physical Volumes
|
||||
|
||||
Remember that you can use pvdisplay /dev/sd{b,c}1 to show information about the newly created PVs.
|
||||
|
||||
**3. Create a VG on top of the PV that you created in the previous step:**
|
||||
|
||||
# vgcreate tecmint_vg /dev/sd{b,c}1
|
||||
|
||||
|
||||
|
||||
Create Volume Group
|
||||
|
||||
Remember that you can use vgdisplay tecmint_vg to show information about the newly created VG.
|
||||
|
||||
**4. Create three logical volumes on top of VG tecmint_vg, as follows:**
|
||||
|
||||
# lvcreate -L 3G -n vol01_docs tecmint_vg [vol01_docs → 3 GB]
|
||||
# lvcreate -L 1G -n vol02_logs tecmint_vg [vol02_logs → 1 GB]
|
||||
# lvcreate -l 100%FREE -n vol03_homes tecmint_vg [vol03_homes → 6 GB]
|
||||
|
||||
|
||||
|
||||
Create Logical Volumes
|
||||
|
||||
Remember that you can use lvdisplay tecmint_vg to show information about the newly created LVs on top of VG tecmint_vg.
|
||||
|
||||
**5. Format each of the logical volumes with xfs (do NOT use xfs if you’re planning on shrinking volumes later!):**
|
||||
|
||||
# mkfs.xfs /dev/tecmint_vg/vol01_docs
|
||||
# mkfs.xfs /dev/tecmint_vg/vol02_logs
|
||||
# mkfs.xfs /dev/tecmint_vg/vol03_homes
|
||||
|
||||
**6. Finally, mount them:**
|
||||
|
||||
# mount /dev/tecmint_vg/vol01_docs /mnt/docs
|
||||
# mount /dev/tecmint_vg/vol02_logs /mnt/logs
|
||||
# mount /dev/tecmint_vg/vol03_homes /mnt/homes
|
||||
|
||||
#### Removing Logical Volumes, Volume Group and Physical Volumes ####
|
||||
|
||||
**7. Now we will reverse the LVM implementation and remove the LVs, the VG, and the PVs:**
|
||||
|
||||
# lvremove /dev/tecmint_vg/vol01_docs
|
||||
# lvremove /dev/tecmint_vg/vol02_logs
|
||||
# lvremove /dev/tecmint_vg/vol03_homes
|
||||
# vgremove /dev/tecmint_vg
|
||||
# pvremove /dev/sd{b,c}1
|
||||
|
||||
**8. Now let’s install SSM and we will see how to perform the above in ONLY 1 STEP!**
|
||||
|
||||
# yum update && yum install system-storage-manager
|
||||
|
||||
We will use the same names and sizes as before:
|
||||
|
||||
# ssm create -s 3G -n vol01_docs -p tecmint_vg --fstype ext4 /mnt/docs /dev/sd{b,c}1
|
||||
# ssm create -s 1G -n vol02_logs -p tecmint_vg --fstype ext4 /mnt/logs /dev/sd{b,c}1
|
||||
# ssm create -n vol03_homes -p tecmint_vg --fstype ext4 /mnt/homes /dev/sd{b,c}1
|
||||
|
||||
Yes! SSM will let you:
|
||||
|
||||
- initialize block devices as physical volumes
|
||||
- create a volume group
|
||||
- create logical volumes
|
||||
- format LVs, and
|
||||
- mount them using only one command
|
||||
|
||||
**9. We can now display the information about PVs, VGs, or LVs, respectively, as follows:**
|
||||
|
||||
# ssm list dev
|
||||
# ssm list pool
|
||||
# ssm list vol
|
||||
|
||||
|
||||
|
||||
Check Information of PVs, VGs, or LVs
|
||||
|
||||
**10. As we already know, one of the distinguishing features of LVM is the possibility to resize (expand or decrease) logical volumes without downtime.**
|
||||
|
||||
Say we are running out of space in vol02_logs but have plenty of space in vol03_homes. We will resize vol03_homes to 4 GB and expand vol02_logs to use the remaining space:
|
||||
|
||||
# ssm resize -s 4G /dev/tecmint_vg/vol03_homes
|
||||
|
||||
Run ssm list pool again and take note of the free space in tecmint_vg:
|
||||
|
||||
|
||||
|
||||
Check Volume Size
|
||||
|
||||
Then do:
|
||||
|
||||
# ssm resize -s+1.99 /dev/tecmint_vg/vol02_logs
|
||||
|
||||
**Note**: that the plus sign after the -s flag indicates that the specified value should be added to the present value.
|
||||
|
||||
**11. Removing logical volumes and volume groups is much easier with ssm as well. A simple,**
|
||||
|
||||
# ssm remove tecmint_vg
|
||||
|
||||
will return a prompt asking you to confirm the deletion of the VG and the LVs it contains:
|
||||
|
||||
|
||||
|
||||
Remove Logical Volume and Volume Group
|
||||
|
||||
### Managing Encrypted Volumes ###
|
||||
|
||||
SSM also provides system administrators with the capability of managing encryption for new or existing volumes. You will need the cryptsetup package installed first:
|
||||
|
||||
# yum update && yum install cryptsetup
|
||||
|
||||
Then issue the following command to create an encrypted volume. You will be prompted to enter a passphrase to maximize security:
|
||||
|
||||
# ssm create -s 3G -n vol01_docs -p tecmint_vg --fstype ext4 --encrypt luks /mnt/docs /dev/sd{b,c}1
|
||||
# ssm create -s 1G -n vol02_logs -p tecmint_vg --fstype ext4 --encrypt luks /mnt/logs /dev/sd{b,c}1
|
||||
# ssm create -n vol03_homes -p tecmint_vg --fstype ext4 --encrypt luks /mnt/homes /dev/sd{b,c}1
|
||||
|
||||
Our next task consists in adding the corresponding entries in /etc/fstab in order for those logical volumes to be available on boot. Rather than using the device identifier (/dev/something).
|
||||
|
||||
We will use each LV’s UUID (so that our devices will still be uniquely identified should we add other logical volumes or devices), which we can find out with the blkid utility:
|
||||
|
||||
# blkid -o value UUID /dev/tecmint_vg/vol01_docs
|
||||
# blkid -o value UUID /dev/tecmint_vg/vol02_logs
|
||||
# blkid -o value UUID /dev/tecmint_vg/vol03_homes
|
||||
|
||||
In our case:
|
||||
|
||||
|
||||
|
||||
Find Logical Volume UUID
|
||||
|
||||
Next, create the /etc/crypttab file with the following contents (change the UUIDs for the ones that apply to your setup):
|
||||
|
||||
docs UUID=ba77d113-f849-4ddf-8048-13860399fca8 none
|
||||
logs UUID=58f89c5a-f694-4443-83d6-2e83878e30e4 none
|
||||
homes UUID=92245af6-3f38-4e07-8dd8-787f4690d7ac none
|
||||
|
||||
And insert the following entries in /etc/fstab. Note that device_name (/dev/mapper/device_name) is the mapper identifier that appears in the first column of /etc/crypttab.
|
||||
|
||||
# Logical volume vol01_docs:
|
||||
/dev/mapper/docs /mnt/docs ext4 defaults 0 2
|
||||
# Logical volume vol02_logs
|
||||
/dev/mapper/logs /mnt/logs ext4 defaults 0 2
|
||||
# Logical volume vol03_homes
|
||||
/dev/mapper/homes /mnt/homes ext4 defaults 0 2
|
||||
|
||||
Now reboot (systemctl reboot) and you will be prompted to enter the passphrase for each LV. Afterwards you can confirm that the mount operation was successful by checking the corresponding mount points:
|
||||
|
||||
|
||||
|
||||
Verify Logical Volume Mount Points
|
||||
|
||||
### Conclusion ###
|
||||
|
||||
In this tutorial we have started to explore how to set up and configure system storage using classic volume management tools and SSM, which also integrates filesystem and encryption capabilities in one package. This makes SSM an invaluable tool for any sysadmin.
|
||||
|
||||
Let us know if you have any questions or comments – feel free to use the form below to get in touch with us!
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/rhcsa-exam-create-format-resize-delete-and-encrypt-partitions-in-linux/
|
||||
|
||||
作者：[Gabriel Cánepa][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/gacanepa/
|
||||
[1]:http://www.tecmint.com/create-lvm-storage-in-linux/
|
||||
@ -1,3 +1,5 @@
|
||||
FSSlc translating
|
||||
|
||||
RHCSA Series: Using ACLs (Access Control Lists) and Mounting Samba / NFS Shares – Part 7
|
||||
================================================================================
|
||||
In the last article ([RHCSA series Part 6][1]) we started explaining how to set up and configure local system storage using parted and ssm.
|
||||
@ -209,4 +211,4 @@ via: http://www.tecmint.com/rhcsa-exam-configure-acls-and-mount-nfs-samba-shares
|
||||
[a]:http://www.tecmint.com/author/gacanepa/
|
||||
[1]:http://www.tecmint.com/rhcsa-exam-create-format-resize-delete-and-encrypt-partitions-in-linux/
|
||||
[2]:http://www.tecmint.com/rhcsa-exam-manage-users-and-groups/
|
||||
[3]:https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Storage_Administration_Guide/ch-acls.html
|
||||
[3]:https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Storage_Administration_Guide/ch-acls.html
|
||||
|
||||
@ -0,0 +1,147 @@
|
||||
Linux小技巧：Chrome小游戏，文字说话，计划作业，重复执行命令
|
||||
================================================================================
|
||||
|
||||
重要的事情说两遍，我完成了一个[Linux提示与彩蛋][1]系列，让你的Linux获得更多创造和娱乐。
|
||||
|
||||
|
||||
|
||||
Linux提示与彩蛋系列
|
||||
|
||||
本文，我将会讲解Google-chrome内建小游戏，在终端中如何让文字说话，使用‘at’命令设置作业和使用watch命令重复执行命令。
|
||||
|
||||
### 1. Google Chrome 浏览器小游戏彩蛋 ###
|
||||
|
||||
网线脱掉或者其他什么原因连不上网时，Google Chrome就会出现一个小游戏。声明，我并不是游戏玩家，因此我的电脑上并没有安装任何第三方的恶意游戏。安全是第一位。
|
||||
|
||||
所以当Internet发生出错，会出现一个这样的界面：
|
||||
|
||||
|
||||
|
||||
不能连接到互联网
|
||||
|
||||
按下空格键来激活Google-chrome彩蛋游戏。游戏没有时间限制。并且还不需要浪费时间安装使用。
|
||||
|
||||
不需要第三方软件的支持。同样支持Windows和Mac平台，但是我的平台是Linux，我也只谈论Linux。当然在Linux，这个游戏运行很好。游戏简单，但也很花费时间。
|
||||
|
||||
使用空格/向上方向键来跳跃。请看下列截图：
|
||||
|
||||
|
||||
|
||||
Google Chrome中玩游戏
|
||||
|
||||
### 2. Linux 终端中朗读文字 ###
|
||||
|
||||
对于那些不能文字朗读的设备，有个小工具可以实现文字说话的转换器。
|
||||
espeak支持多种语言，可以及时朗读输入文字。
|
||||
|
||||
系统应该默认安装了Espeak，如果你的系统没有安装，你可以使用下列命令来安装：
|
||||
|
||||
# apt-get install espeak (Debian)
|
||||
# yum install espeak (CentOS)
|
||||
# dnf install espeak (Fedora 22 onwards)
|
||||
|
||||
You may ask espeak to accept Input Interactively from standard Input device and convert it to speech for you. You may do:
|
||||
你可以设置接受从标准输入的交互地输入并及时转换成语音朗读出来。这样设置：
|
||||
|
||||
$ espeak [按回车键]
|
||||
|
||||
更详细的输出你可以这样做：
|
||||
|
||||
$ espeak --stdout | aplay [按回车键][这里需要双击]
|
||||
|
||||
espeak设置灵活，也可以朗读文本文件。你可以这样设置：
|
||||
|
||||
$ espeak --stdout /path/to/text/file/file_name.txt | aplay [Hit Enter]
|
||||
|
||||
espeak可以设置朗读速度。默认速度是160词每分钟。使用-s参数来设置。
|
||||
|
||||
设置30词每分钟：
|
||||
|
||||
$ espeak -s 30 -f /path/to/text/file/file_name.txt | aplay
|
||||
|
||||
设置200词每分钟：
|
||||
|
||||
$ espeak -s 200 -f /path/to/text/file/file_name.txt | aplay
|
||||
|
||||
让其他语言说北印度语（作者母语），这样设置：
|
||||
|
||||
$ espeak -v hindi --stdout 'टेकमिंट विश्व की एक बेहतरीन लाइंक्स आधारित वेबसाइट है|' | aplay
|
||||
|
||||
espeak支持多种语言，支持自定义设置。使用下列命令来获得语言表：
|
||||
|
||||
$ espeak --voices
|
||||
|
||||
### 3. 快速计划作业 ###
|
||||
|
||||
我们已经非常熟悉使用[cron][2]后台执行一个计划命令。
|
||||
|
||||
Cron是一个Linux系统管理的高级命令，用于计划定时任务如备份或者指定时间或间隔的任何事情。
|
||||
|
||||
但是，你是否知道at命令可以让你计划一个作业或者命令在指定时间？at命令可以指定时间和指定内容执行作业。
|
||||
|
||||
例如，你打算在早上11点2分执行uptime命令，你只需要这样做：
|
||||
|
||||
$ at 11:02
|
||||
uptime >> /home/$USER/uptime.txt
|
||||
Ctrl+D
|
||||
|
||||
|
||||
|
||||
Linux中计划作业
|
||||
|
||||
检查at命令是否成功设置，使用：
|
||||
|
||||
$ at -l
|
||||
|
||||
|
||||
|
||||
浏览计划作业
|
||||
|
||||
at支持计划多个命令，例如：
|
||||
|
||||
$ at 12:30
|
||||
Command – 1
|
||||
Command – 2
|
||||
…
|
||||
command – 50
|
||||
…
|
||||
Ctrl + D
|
||||
|
||||
### 4. 特定时间重复执行命令 ###
|
||||
|
||||
有时，我们可以需要在指定时间间隔执行特定命令。例如，每3秒，想打印一次时间。
|
||||
|
||||
查看现在时间，使用下列命令。
|
||||
|
||||
$ date +"%H:%M:%S
|
||||
|
||||
|
||||
|
||||
Linux中查看日期和时间
|
||||
|
||||
为了查看这个命令每三秒的输出，我需要运行下列命令：
|
||||
|
||||
$ watch -n 3 'date +"%H:%M:%S"'
|
||||
|
||||
|
||||
|
||||
Linux中watch命令
|
||||
|
||||
watch命令的‘-n’开关设定时间间隔。在上诉命令中，我们定义了时间间隔为3秒。你可以按你的需求定义。同样watch
|
||||
也支持其他命令或者脚本。
|
||||
|
||||
至此。希望你喜欢这个系列的文章，让你的linux更有创造性，获得更多快乐。所有的建议欢迎评论。欢迎你也看看其他文章，谢谢。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/text-to-speech-in-terminal-schedule-a-job-and-watch-commands-in-linux/
|
||||
|
||||
作者：[Avishek Kumar][a]
|
||||
译者：[VicYu/Vic020](http://vicyu.net)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/avishek/
|
||||
[1]:http://www.tecmint.com/tag/linux-tricks/
|
||||
[2]:http://www.tecmint.com/11-cron-scheduling-task-examples-in-linux/
|
||||
@ -0,0 +1,269 @@
|
||||
RHCSA 系列：使用 'Parted' 和 'SSM' 来配置和加密系统存储 – Part 6
|
||||
================================================================================
|
||||
在本篇文章中，我们将讨论在 RHEL 7 中如何使用传统的工具来设置和配置本地系统存储，并介绍系统存储管理器(也称为 SSM)，它将极大地简化上面的任务。
|
||||
|
||||
|
||||
|
||||
RHCSA: 配置和加密系统存储 – Part 6
|
||||
|
||||
请注意，我们将在这篇文章中展开这个话题，但由于该话题的宽泛性，我们将在下一期(Part 7)中继续介绍有关它的描述和使用。
|
||||
|
||||
### 在 RHEL 7 中创建和修改分区 ###
|
||||
|
||||
在 RHEL 7 中， parted 是默认的用来处理分区的程序，且它允许你：
|
||||
|
||||
- 展示当前的分区表
|
||||
- 操纵(增加或减少分区的大小)现有的分区
|
||||
- 利用空余的磁盘空间或额外的物理存储设备来创建分区
|
||||
|
||||
强烈建议你在试图增加一个新的分区或对一个现有分区进行更改前，你应当确保设备上没有任何一个分区正在使用(`umount /dev/partition`)，且假如你正使用设备的一部分来作为 swap 分区，在进行上面的操作期间，你需要将它禁用(`swapoff -v /dev/partition`) 。
|
||||
|
||||
实施上面的操作的最简单的方法是使用一个安装介质例如一个 RHEL 7 安装 DVD 或 USB 以急救模式启动 RHEL(Troubleshooting → Rescue a Red Hat Enterprise Linux system)，然后当让你选择一个选项来挂载现有的 Linux 安装时，选择'跳过'这个选项，接着你将看到一个命令行提示符，在其中你可以像下图显示的那样开始键入与在一个未被使用的物理设备上创建一个正常的分区时所用的相同的命令。
|
||||
|
||||
|
||||
|
||||
RHEL 7 急救模式
|
||||
|
||||
要启动 parted，只需键入：
|
||||
|
||||
# parted /dev/sdb
|
||||
|
||||
其中 `/dev/sdb` 是你将要创建新分区所在的设备；然后键入 `print` 来显示当前设备的分区表：
|
||||
|
||||
|
||||
|
||||
创建新的分区
|
||||
|
||||
正如你所看到的那样，在这个例子中，我们正在使用一个 5 GB 的虚拟光驱。现在我们将要创建一个 4 GB 的主分区，然后将它格式化为 xfs 文件系统，它是 RHEL 7 中默认的文件系统。
|
||||
|
||||
你可以从一系列的文件系统中进行选择。你将需要使用 mkpart 来手动地创建分区，接着和平常一样，用 mkfs.fstype 来对分区进行格式化，因为 mkpart 并不支持许多现代的文件系统以达到即开即用。
|
||||
|
||||
在下面的例子中，我们将为设备设定一个标记，然后在 `/dev/sdb` 上创建一个主分区 `(p)`，它从设备的 0% 开始，并在 4000MB(4 GB) 处结束。
|
||||
|
||||
|
||||
|
||||
标记分区的名称
|
||||
|
||||
接下来，我们将把分区格式化为 xfs 文件系统，然后再次打印出分区表，以此来确保更改已被应用。
|
||||
|
||||
# mkfs.xfs /dev/sdb1
|
||||
# parted /dev/sdb print
|
||||
|
||||
|
||||
|
||||
格式化分区为 XFS 文件系统
|
||||
|
||||
对于旧一点的文件系统，在 parted 中你应该使用 `resize` 命令来改变分区的大小。不幸的是，这只适用于 ext2, fat16, fat32, hfs, linux-swap, 和 reiserfs (若 libreiserfs 已被安装)。
|
||||
|
||||
因此，改变分区大小的唯一方式是删除它然后再创建它(所以确保你对你的数据做了完整的备份！)。毫无疑问，在 RHEL 7 中默认的分区方案是基于 LVM 的。
|
||||
|
||||
使用 parted 来移除一个分区，可以用：
|
||||
|
||||
# parted /dev/sdb print
|
||||
# parted /dev/sdb rm 1
|
||||
|
||||
|
||||
|
||||
移除或删除分区
|
||||
|
||||
### 逻辑卷管理(LVM) ###
|
||||
|
||||
一旦一个磁盘被分好了分区，再去更改分区的大小就是一件困难或冒险的事了。基于这个原因，假如我们计划在我们的系统上对分区的大小进行更改，我们应当考虑使用 LVM 的可能性，而不是使用传统的分区系统。这样多个物理设备可以组成一个逻辑组，以此来寄宿可自定义数目的逻辑卷，而逻辑卷的增大或减少不会带来任何麻烦。
|
||||
|
||||
简单来说，你会发现下面的示意图对记住 LVM 的基础架构或许有用。
|
||||
|
||||
|
||||
|
||||
LVM 的基本架构
|
||||
|
||||
#### 创建物理卷，卷组和逻辑卷 ####
|
||||
|
||||
遵循下面的步骤是为了使用传统的卷管理工具来设置 LVM。由于你可以通过阅读这个网站上的 LVM 系列来扩展这个话题，我将只是概要的介绍设置 LVM 的基本步骤，然后与使用 SSM 来实现相同功能做个比较。
|
||||
|
||||
**注**: 我们将使用整个磁盘 `/dev/sdb` 和 `/dev/sdc` 来作为 PVs (物理卷)，但是否执行相同的操作完全取决于你。
|
||||
|
||||
**1. 使用 /dev/sdb 和 /dev/sdc 中 100% 的可用磁盘空间来创建分区 `/dev/sdb1` 和 `/dev/sdc1`：**
|
||||
|
||||
# parted /dev/sdb print
|
||||
# parted /dev/sdc print
|
||||
|
||||
|
||||
|
||||
创建新分区
|
||||
|
||||
**2. 分别在 /dev/sdb1 和 /dev/sdc1 上共创建 2 个物理卷。**
|
||||
|
||||
# pvcreate /dev/sdb1
|
||||
# pvcreate /dev/sdc1
|
||||
|
||||
|
||||
|
||||
创建两个物理卷
|
||||
|
||||
记住，你可以使用 pvdisplay /dev/sd{b,c}1 来显示有关新建的 PV 的信息。
|
||||
|
||||
**3. 在上一步中创建的 PV 之上创建一个 VG：**
|
||||
|
||||
# vgcreate tecmint_vg /dev/sd{b,c}1
|
||||
|
||||
|
||||
|
||||
创建卷组
|
||||
|
||||
记住，你可使用 vgdisplay tecmint_vg 来显示有关新建的 VG 的信息。
|
||||
|
||||
**4. 像下面那样，在 VG tecmint_vg 之上创建 3 个逻辑卷：**
|
||||
|
||||
# lvcreate -L 3G -n vol01_docs tecmint_vg [vol01_docs → 3 GB]
|
||||
# lvcreate -L 1G -n vol02_logs tecmint_vg [vol02_logs → 1 GB]
|
||||
# lvcreate -l 100%FREE -n vol03_homes tecmint_vg [vol03_homes → 6 GB]
|
||||
|
||||
|
||||
|
||||
创建逻辑卷
|
||||
|
||||
记住，你可以使用 lvdisplay tecmint_vg 来显示有关在 VG tecmint_vg 之上新建的 LV 的信息。
|
||||
|
||||
**5. 格式化每个逻辑卷为 xfs 文件系统格式(假如你计划在以后将要缩小卷的大小，请别使用 xfs 文件系统格式！)：**
|
||||
|
||||
# mkfs.xfs /dev/tecmint_vg/vol01_docs
|
||||
# mkfs.xfs /dev/tecmint_vg/vol02_logs
|
||||
# mkfs.xfs /dev/tecmint_vg/vol03_homes
|
||||
|
||||
**6. 最后，挂载它们：**
|
||||
|
||||
# mount /dev/tecmint_vg/vol01_docs /mnt/docs
|
||||
# mount /dev/tecmint_vg/vol02_logs /mnt/logs
|
||||
# mount /dev/tecmint_vg/vol03_homes /mnt/homes
|
||||
|
||||
#### 移除逻辑卷，卷组和物理卷 ####
|
||||
|
||||
**7.现在我们将进行与刚才相反的操作并移除 LV，VG 和 PV：**
|
||||
|
||||
# lvremove /dev/tecmint_vg/vol01_docs
|
||||
# lvremove /dev/tecmint_vg/vol02_logs
|
||||
# lvremove /dev/tecmint_vg/vol03_homes
|
||||
# vgremove /dev/tecmint_vg
|
||||
# pvremove /dev/sd{b,c}1
|
||||
|
||||
**8. 现在，让我们来安装 SSM，我们将看到如何只用一步就完成上面所有的操作！**
|
||||
|
||||
# yum update && yum install system-storage-manager
|
||||
|
||||
我们将和上面一样，使用相同的名称和大小：
|
||||
|
||||
# ssm create -s 3G -n vol01_docs -p tecmint_vg --fstype ext4 /mnt/docs /dev/sd{b,c}1
|
||||
# ssm create -s 1G -n vol02_logs -p tecmint_vg --fstype ext4 /mnt/logs /dev/sd{b,c}1
|
||||
# ssm create -n vol03_homes -p tecmint_vg --fstype ext4 /mnt/homes /dev/sd{b,c}1
|
||||
|
||||
是的! SSM 可以让你：
|
||||
|
||||
- 初始化块设备来作为物理卷
|
||||
- 创建一个卷组
|
||||
- 创建逻辑卷
|
||||
- 格式化 LV 和
|
||||
- 只使用一个命令来挂载它们
|
||||
|
||||
**9. 现在，我们可以使用下面的命令来展示有关 PV，VG 或 LV 的信息：**
|
||||
|
||||
# ssm list dev
|
||||
# ssm list pool
|
||||
# ssm list vol
|
||||
|
||||
|
||||
|
||||
检查有关 PV, VG,或 LV 的信息
|
||||
|
||||
**10. 正如我们知道的那样， LVM 的一个显著的特点是可以在不停机的情况下更改(增大或缩小) 逻辑卷的大小：**
|
||||
|
||||
假定在 vol02_logs 上我们用尽了空间，而 vol03_homes 还留有足够的空间。我们将把 vol03_homes 的大小调整为 4 GB，并使用剩余的空间来扩展 vol02_logs：
|
||||
|
||||
# ssm resize -s 4G /dev/tecmint_vg/vol03_homes
|
||||
|
||||
再次运行 `ssm list pool`，并记录 tecmint_vg 中的剩余空间的大小：
|
||||
|
||||
|
||||
|
||||
查看卷的大小
|
||||
|
||||
然后执行：
|
||||
|
||||
# ssm resize -s+1.99 /dev/tecmint_vg/vol02_logs
|
||||
|
||||
**注**: 在 `-s` 后的加号暗示特定值应该被加到当前值上。
|
||||
|
||||
**11. 使用 ssm 来移除逻辑卷和卷组也更加简单，只需使用：**
|
||||
|
||||
# ssm remove tecmint_vg
|
||||
|
||||
这个命令将返回一个提示，询问你是否确认删除 VG 和它所包含的 LV：
|
||||
|
||||
|
||||
|
||||
移除逻辑卷和卷组
|
||||
|
||||
### 管理加密的卷 ###
|
||||
|
||||
SSM 也给系统管理员提供了为新的或现存的卷加密的能力。首先，你将需要安装 cryptsetup 软件包：
|
||||
|
||||
# yum update && yum install cryptsetup
|
||||
|
||||
然后写出下面的命令来创建一个加密卷，你将被要求输入一个密码来增强安全性：
|
||||
|
||||
# ssm create -s 3G -n vol01_docs -p tecmint_vg --fstype ext4 --encrypt luks /mnt/docs /dev/sd{b,c}1
|
||||
# ssm create -s 1G -n vol02_logs -p tecmint_vg --fstype ext4 --encrypt luks /mnt/logs /dev/sd{b,c}1
|
||||
# ssm create -n vol03_homes -p tecmint_vg --fstype ext4 --encrypt luks /mnt/homes /dev/sd{b,c}1
|
||||
|
||||
我们的下一个任务是往 /etc/fstab 中添加条目来让这些逻辑卷在启动时可用，而不是使用设备识别编号(/dev/something)。
|
||||
|
||||
我们将使用每个 LV 的 UUID (使得当我们添加其他的逻辑卷或设备后，我们的设备仍然可以被唯一的标记)，而我们可以使用 blkid 应用来找到它们的 UUID：
|
||||
|
||||
# blkid -o value UUID /dev/tecmint_vg/vol01_docs
|
||||
# blkid -o value UUID /dev/tecmint_vg/vol02_logs
|
||||
# blkid -o value UUID /dev/tecmint_vg/vol03_homes
|
||||
|
||||
在我们的例子中：
|
||||
|
||||
|
||||
|
||||
找到逻辑卷的 UUID
|
||||
|
||||
接着，使用下面的内容来创建 /etc/crypttab 文件(请更改 UUID 来适用于你的设置)：
|
||||
|
||||
docs UUID=ba77d113-f849-4ddf-8048-13860399fca8 none
|
||||
logs UUID=58f89c5a-f694-4443-83d6-2e83878e30e4 none
|
||||
homes UUID=92245af6-3f38-4e07-8dd8-787f4690d7ac none
|
||||
|
||||
然后在 /etc/fstab 中添加如下的条目。请注意到 device_name (/dev/mapper/device_name) 是出现在 /etc/crypttab 中第一列的映射标识：
|
||||
|
||||
# Logical volume vol01_docs:
|
||||
/dev/mapper/docs /mnt/docs ext4 defaults 0 2
|
||||
# Logical volume vol02_logs
|
||||
/dev/mapper/logs /mnt/logs ext4 defaults 0 2
|
||||
# Logical volume vol03_homes
|
||||
/dev/mapper/homes /mnt/homes ext4 defaults 0 2
|
||||
|
||||
现在重启(systemctl reboot)，则你将被要求为每个 LV 输入密码。随后，你可以通过检查相应的挂载点来确保挂载操作是否成功：
|
||||
|
||||
|
||||
|
||||
确保逻辑卷挂载点
|
||||
|
||||
### 总结 ###
|
||||
|
||||
在这篇教程中，我们开始探索如何使用传统的卷管理工具和 SSM 来设置和配置系统存储，SSM 也在一个软件包中集成了文件系统和加密功能。这使得对于任何系统管理员来说，SSM 是一个非常有价值的工具。
|
||||
|
||||
假如你有任何的问题或评论，请让我们知晓 – 请随意使用下面的评论框来与我们保存联系！
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/rhcsa-exam-create-format-resize-delete-and-encrypt-partitions-in-linux/
|
||||
|
||||
作者：[Gabriel Cánepa][a]
|
||||
译者：[FSSlc](https://github.com/FSSlc)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/gacanepa/
|
||||
[1]:http://www.tecmint.com/create-lvm-storage-in-linux/
|
||||
Loading…
Reference in New Issue
Block a user