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sources/tech/20190104 Three Ways To Reset And Change Forgotten Root Password on RHEL 7-CentOS 7 Systems.md
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255 lines
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[#]: collector: (lujun9972)
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[#]: translator: ( )
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[#]: reviewer: ( )
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[#]: publisher: ( )
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[#]: url: ( )
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[#]: subject: (Three Ways To Reset And Change Forgotten Root Password on RHEL 7/CentOS 7 Systems)
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[#]: via: (https://www.2daygeek.com/linux-reset-change-forgotten-root-password-in-rhel-7-centos-7/)
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[#]: author: (Prakash Subramanian https://www.2daygeek.com/author/prakash/)
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Three Ways To Reset And Change Forgotten Root Password on RHEL 7/CentOS 7 Systems
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======
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If you are forget to remember your root password for RHEL 7 and CentOS 7 systems and want to reset the forgotten root password?
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If so, don’t worry we are here to help you out on this.
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Navigate to the following link if you want to **[reset forgotten root password on RHEL 6/CentOS 6][1]**.
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This is generally happens when you use different password in vast environment or if you are not maintaining the proper inventory.
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Whatever it is. No issues, we will help you through this article.
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It can be done in many ways but we are going to show you the best three methods which we tried many times for our clients.
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In Linux servers there are three different users are available. These are, Normal User, System User and Super User.
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As everyone knows the Root user is known as super user in Linux and Administrator is in Windows.
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We can’t perform any major activity without root password so, make sure you should have the right root password when you perform any major tasks.
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If you don’t know or don’t have it, try to reset using one of the below method.
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* Reset Forgotten Root Password By Booting into Single User Mode using `rd.break`
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* Reset Forgotten Root Password By Booting into Single User Mode using `init=/bin/bash`
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* Reset Forgotten Root Password By Booting into Rescue Mode
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### Method-1: Reset Forgotten Root Password By Booting into Single User Mode
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Just follow the below procedure to reset the forgotten root password in RHEL 7/CentOS 7 systems.
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To do so, reboot your system and follow the instructions carefully.
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**`Step-1:`** Reboot your system and interrupt at the boot menu by hitting **`e`** key to modify the kernel arguments.
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![][3]
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**`Step-2:`** In the GRUB options, find `linux16` word and add the `rd.break` word in the end of the file then press `Ctrl+x` or `F10` to boot into single user mode.
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![][4]
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**`Step-3:`** At this point of time, your root filesystem will be mounted in Read only (RO) mode to /sysroot. Run the below command to confirm this.
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```
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# mount | grep root
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```
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![][5]
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**`Step-4:`** Based on the above output, i can say that i’m in single user mode and my root file system is mounted in read only mode.
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It won’t allow you to make any changes on your system until you mount the root filesystem with Read and write (RW) mode to /sysroot. To do so, use the following command.
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```
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# mount -o remount,rw /sysroot
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```
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![][6]
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**`Step-5:`** Currently your file systems are mounted as a temporary partition. Now, your command prompt shows **switch_root:/#**.
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Run the following command to get into a chroot jail so that /sysroot is used as the root of the file system.
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```
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# chroot /sysroot
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```
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![][7]
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**`Step-6:`** Now you can able to reset the root password with help of `passwd` command.
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```
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# echo "CentOS7$#123" | passwd --stdin root
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```
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![][8]
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**`Step-7:`** By default CentOS 7/RHEL 7 use SELinux in enforcing mode, so create a following hidden file which will automatically perform a relabel of all files on next boot.
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It allow us to fix the context of the **/etc/shadow** file.
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```
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# touch /.autorelabel
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```
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![][9]
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**`Step-8:`** Issue `exit` twice to exit from the chroot jail environment and reboot the system.
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![][10]
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**`Step-9:`** Now you can login to your system with your new password.
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![][11]
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### Method-2: Reset Forgotten Root Password By Booting into Single User Mode
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Alternatively we can use the below procedure to reset the forgotten root password in RHEL 7/CentOS 7 systems.
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**`Step-1:`** Reboot your system and interrupt at the boot menu by hitting **`e`** key to modify the kernel arguments.
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![][3]
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**`Step-2:`** In the GRUB options, find `rhgb quiet` word and replace with the `init=/bin/bash` or `init=/bin/sh` word then press `Ctrl+x` or `F10` to boot into single user mode.
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Screenshot for **`init=/bin/bash`**.
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![][12]
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Screenshot for **`init=/bin/sh`**.
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![][13]
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**`Step-3:`** At this point of time, your root system will be mounted in Read only mode to /. Run the below command to confirm this.
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```
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# mount | grep root
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```
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![][14]
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**`Step-4:`** Based on the above ouput, i can say that i’m in single user mode and my root file system is mounted in read only (RO) mode.
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It won’t allow you to make any changes on your system until you mount the root file system with Read and write (RW) mode. To do so, use the following command.
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```
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# mount -o remount,rw /
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```
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![][15]
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**`Step-5:`** Now you can able to reset the root password with help of `passwd` command.
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```
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# echo "RHEL7$#123" | passwd --stdin root
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```
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![][16]
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**`Step-6:`** By default CentOS 7/RHEL 7 use SELinux in enforcing mode, so create a following hidden file which will automatically perform a relabel of all files on next boot.
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It allow us to fix the context of the **/etc/shadow** file.
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```
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# touch /.autorelabel
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```
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![][17]
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**`Step-7:`** Finally `Reboot` the system.
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```
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# exec /sbin/init 6
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```
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![][18]
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**`Step-9:`** Now you can login to your system with your new password.
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![][11]
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### Method-3: Reset Forgotten Root Password By Booting into Rescue Mode
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Alternatively, we can reset the forgotten Root password for RHEL 7 and CentOS 7 systems using Rescue mode.
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**`Step-1:`** Insert the bootable media through USB or DVD drive which is compatible for you and reboot your system. It will take to you to the below screen.
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Hit `Troubleshooting` to launch the `Rescue` mode.
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![][19]
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**`Step-2:`** Choose `Rescue a CentOS system` and hit `Enter` button.
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![][20]
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**`Step-3:`** Here choose `1` and the rescue environment will now attempt to find your Linux installation and mount it under the directory `/mnt/sysimage`.
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![][21]
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**`Step-4:`** Simple hit `Enter` to get a shell.
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![][22]
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**`Step-5:`** Run the following command to get into a chroot jail so that /mnt/sysimage is used as the root of the file system.
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```
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# chroot /mnt/sysimage
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```
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![][23]
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**`Step-6:`** Now you can able to reset the root password with help of **passwd** command.
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```
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# echo "RHEL7$#123" | passwd --stdin root
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```
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![][24]
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**`Step-7:`** By default CentOS 7/RHEL 7 use SELinux in enforcing mode, so create a following hidden file which will automatically perform a relabel of all files on next boot.
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It allow us to fix the context of the /etc/shadow file.
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```
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# touch /.autorelabel
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```
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![][25]
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**`Step-8:`** Remove the bootable media then initiate the reboot.
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**`Step-9:`** Issue `exit` twice to exit from the chroot jail environment and reboot the system.
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![][26]
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**`Step-10:`** Now you can login to your system with your new password.
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![][11]
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--------------------------------------------------------------------------------
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via: https://www.2daygeek.com/linux-reset-change-forgotten-root-password-in-rhel-7-centos-7/
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作者：[Prakash Subramanian][a]
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选题：[lujun9972][b]
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译者：[译者ID](https://github.com/译者ID)
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校对：[校对者ID](https://github.com/校对者ID)
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本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
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[a]: https://www.2daygeek.com/author/prakash/
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[b]: https://github.com/lujun9972
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[1]: https://www.2daygeek.com/linux-reset-change-forgotten-root-password-in-rhel-6-centos-6/
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[2]: data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
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