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如何在 Linux 中从 NetworkManager 切换为 systemd-network How to switch from NetworkManager to systemd-networkd on Linux
在 Linux 世界里， systemd 的采用一直是激烈争论的主题，它的支持者和反对者之间的战火仍然在燃烧。到了今天，大部分主流 Linux 发行版都已经采用了 systemd 作为默认初始化系统。 In the world of Linux, adoption of systemd has been a subject of heated controversy, and the debate between its proponents and critics is still going on. As of today, most major Linux distributions have adopted systemd as a default init system.
正如其作者所说，作为一个 “从未完成、从未完善、但一直追随技术进步” 的系统，systemd 已经不只是一个初始化进程，它被设计为一个更广泛的系统以及服务管理平台，这个；平台包括了不断增长的核心系统进程、库和工具的生态系统。 Billed as a "never finished, never complete, but tracking progress of technology" by its author, systemd is not just the init daemon, but is designed as a more broad system and service management platform which encompasses the growing ecosystem of core system daemons, libraries and utilities.
systemd 的其中一部分是 systemd-networkd，它负责 systemd 生态中的网络配置。使用 systemd-networkd，你可以为网络设备配置基础的 DHCP/静态 IP 网络。它还可以配置虚拟网络功能，例如网桥、隧道和 VLAN。systemd-networkd 目前还不能直接支持无线网络，但你可以使用 wpa_supplicant 服务配置无线适配器，然后用 systemd-networkd 挂钩起来。 One of many additions to systemd is systemd-networkd, which is responsible for network configuration within the systemd ecosystem. Using systemd-networkd, you can configure basic DHCP/static IP networking for network devices. It can also configure virtual networking features such as bridges, tunnels or VLANs. Wireless networking is not directly handled by systemd-networkd, but you can use wpa_supplicant service to configure wireless adapters, and then hook it up with systemd-networkd.
在很多 Linux 发行版中，NetworkManager 仍然作为默认的网络配置管理器。和 NetworkManager 相比，systemd-networkd 仍处于活跃的开发状态，还缺少一些功能。例如，它还不能像 NetworkManager 那样能在任何时候让你的计算机在多种接口之间保持连接。它还没有为高级脚本提供 ifup/ifdown 钩子函数。但是，systemd-networkd 和其它 systemd 组件（例如用于域名解析的 resolved、NTP 的timesyncd，用于命名的 udevd）结合的非常好。随着时间增长，systemd-networkd只会在 systemd 环境中扮演越来越重要的角色。 On many Linux distributions, NetworkManager has been and is still used as a default network configuration manager. Compared to NetworkManager, systemd-networkd is still under active development, and missing features. For example, it does not have NetworkManager's intelligence to keep your computer connected across various interfaces at all times. It does not provide ifup/ifdown hooks for advanced scripting. Yet, systemd-networkd is integrated well with the rest of systemd components (e.g., resolved for DNS, timesyncd for NTP, udevd for naming), and the role of systemd-networkd may only grow over time in the systemd environment.
如果你对 systemd-networkd 的进步感到高兴，从 NetworkManager 切换到 systemd-networkd 是值得你考虑的一件事。如果你强烈反对 systemd，对 NetworkManager 或基础网络服务感到很满意，那也很好。 If you are happy with the way systemd is evolving, one thing you can consider is to switch from NetworkManager to systemd-networkd. If you are feverishly against systemd, and perfectly happy with NetworkManager or basic network service, that is totally cool.
但对于那些想尝试 systemd-networkd 的人，可以继续看下去，在这篇指南中学会在 Linux 中怎么从 NetworkManager 切换到 systemd-networkd。 But for those of you who want to try out systemd-networkd, you can read on, and find out in this tutorial how to switch from NetworkManager to systemd-networkd on Linux.
需求
Requirement
systemd 210 或更高版本提供了 systemd-networkd。因此诸如 Debian 8 "Jessie" (systemd 215)、 Fedora 21 (systemd 217)、 Ubuntu 15.04 (systemd 219) 或更高版本的 Linux 发行版和 systemd-networkd 兼容。 systemd-networkd is available in systemd version 210 and higher. Thus distributions like Debian 8 "Jessie" (systemd 215), Fedora 21 (systemd 217), Ubuntu 15.04 (systemd 219) or later are compatible with systemd-networkd.
对于其它发行版，在开始下一步之前先检查一下你的 systemd 版本。 For other distributions, check the version of your systemd before proceeding.
$ systemctl --version
从 NetworkManager 切换到 Systemd-networkd
Switch from Network Manager to Systemd-Networkd
从 NetworkManager 切换到 systemd-networkd 其实非常简答（反过来也一样）。 It is relatively straightforward to switch from Network Manager to systemd-networkd (and vice versa).
首先，按照下面这样先停用 NetworkManager 服务，然后启用 systemd-networkd。 First, disable Network Manager service, and enable systemd-networkd as follows.
$ sudo systemctl disable NetworkManager
$ sudo systemctl enable systemd-networkd
你还要启用 systemd-resolved 服务，systemd-networkd用它来进行域名解析。该服务还实现了一个缓存式 DNS 服务器。 You also need to enable systemd-resolved service, which is used by systemd-networkd for network name resolution. This service implements a caching DNS server.
$ sudo systemctl enable systemd-resolved
$ sudo systemctl start systemd-resolved
一旦启动，systemd-resolved 就会在 /run/systemd 目录下某个地方创建它自己的 resolv.conf。但是，把 DNS 解析信息存放在 /etc/resolv.conf 是更普遍的做法，很多应用程序也会依赖于 /etc/resolv.conf。因此为了兼容性，按照下面的方式创建一个到 /etc/resolv.conf 的符号链接。 Once started, systemd-resolved will create its own resolv.conf somewhere under /run/systemd directory. However, it is a common practise to store DNS resolver information in /etc/resolv.conf, and many applications still rely on /etc/resolv.conf. Thus for compatibility reason, create a symlink to /etc/resolv.conf as follows.
$ sudo rm /etc/resolv.conf
$ sudo ln -s /run/systemd/resolve/resolv.conf /etc/resolv.conf
用 systemd-networkd 配置网络连接
Configure Network Connections with Systemd-networkd
要用 systemd-networkd 配置网络服务，你必须指定带.network 扩展名的配置信息文本文件。这些网络配置文件保存到 /etc/systemd/network 并从这里加载。当有多个文件时，systemd-networkd 会按照词汇顺序一个个加载并处理。 To configure network devices with systemd-networkd, you must specify configuration information in text files with .network extension. These network configuration files are then stored and loaded from /etc/systemd/network. When there are multiple files, systemd-networkd loads and processes them one by one in lexical order.
首先创建 /etc/systemd/network 目录。 Let's start by creating a folder /etc/systemd/network.
$ sudo mkdir /etc/systemd/network
DHCP 网络
DHCP Networking
首先来配置 DHCP 网络。对于此，先要创建下面的配置文件。文件名可以任意，但记住文件是按照词汇顺序处理的。 Let's configure DHCP networking first. For this, create the following configuration file. The name of a file can be arbitrary, but remember that files are processed in lexical order.
$ sudo vi /etc/systemd/network/20-dhcp.network
[Match]
Name=enp3*
[Network]
DHCP=yes
正如你上面看到的，每个网络配置文件包括了一个多多个 “sections”，每个 “section”都用 [XXX] 开头。每个 section 包括了一个或多个键值对。[Match] 部分决定这个配置文件配置哪个（些）网络设备。例如，这个文件匹配所有名称以 ens3 开头的网络设备（例如 enp3s0、 enp3s1、 enp3s2 等等）对于匹配的接口，然后启用 [Network] 部分指定的 DHCP 网络配置。 As you can see above, each network configuration file contains one or more "sections" with each section preceded by [XXX] heading. Each section contains one or more key/value pairs. The [Match] section determine which network device(s) are configured by this configuration file. For example, this file matches any network interface whose name starts with ens3 (e.g., enp3s0, enp3s1, enp3s2, etc). For matched interface(s), it then applies DHCP network configuration specified under [Network] section.
静态 IP 网络
Static IP Networking
如果你想给网络设备分配一个静态 IP 地址，那就新建下面的配置文件。 If you want to assign a static IP address to a network interface, create the following configuration file.
$ sudo vi /etc/systemd/network/10-static-enp3s0.network
[Match]
Name=enp3s0
[Network]
Address=192.168.10.50/24
Gateway=192.168.10.1
DNS=8.8.8.8
正如你猜测的， enp3s0 接口地址会被指定为 192.168.10.50/24，默认网关是 192.168.10.1， DNS 服务器是 8.8.8.8。这里微妙的一点是，接口名 enp3s0 事实上也匹配了之前 DHCP 配置中定义的模式规则。但是，根据词汇顺序，文件 "10-static-enp3s0.network" 在 "20-dhcp.network" 之前被处理，对于 enp3s0 接口静态配置比 DHCP 配置有更高的优先级。 As you can guess, the interface enp3s0 will be assigned an address 192.168.10.50/24, a default gateway 192.168.10.1, and a DNS server 8.8.8.8. One subtlety here is that the name of an interface enp3s0, in facts, matches the pattern rule defined in the earlier DHCP configuration as well. However, since the file "10-static-enp3s0.network" is processed before "20-dhcp.network" according to lexical order, the static configuration takes priority over DHCP configuration in case of enp3s0 interface.
一旦你完成了创建配置文件，重启 systemd-networkd 服务或者重启机器。 Once you are done with creating configuration files, restart systemd-networkd service or reboot.
$ sudo systemctl restart systemd-networkd
运行以下命令检查服务状态： Check the status of the service by running:
$ systemctl status systemd-networkd
$ systemctl status systemd-resolved
用 systemd-networkd 配置虚拟网络设备
Configure Virtual Network Devices with Systemd-networkd
systemd-networkd 同样允许你配置虚拟网络设备，例如网桥、VLAN、隧道、VXLAN、绑定等。你必须在用 .netdev 作为扩展名的文件中配置这些虚拟设备。 systemd-networkd also allows you to configure virtual network devices such as bridges, VLANs, tunnel, VXLAN, bonding, etc. You must configure these virtual devices in files with .netdev extension.
这里我展示了如何配置一个桥接接口。 Here I'll show how to configure a bridge interface.
Linux 网桥
Linux Bridge
如果你想创建一个 Linux 网桥(br0) 并把物理接口(eth1) 添加到网桥，你可以新建下面的配置。 If you want to create a Linux bridge (br0) and add a physical interface (eth1) to the bridge, create the following configuration.
$ sudo vi /etc/systemd/network/bridge-br0.netdev
[NetDev]
Name=br0
Kind=bridge
然后按照下面这样用 .network 文件配置网桥接口 br0 和从接口 eth1。 Then configure the bridge interface br0 and the slave interface eth1 using .network files as follows.
$ sudo vi /etc/systemd/network/bridge-br0-slave.network
[Match]
Name=eth1
[Network]
Bridge=br0
$ sudo vi /etc/systemd/network/bridge-br0.network
[Match]
Name=br0
[Network]
Address=192.168.10.100/24
Gateway=192.168.10.1
DNS=8.8.8.8
最后，重启 systemd-networkd。 Finally, restart systemd-networkd:
$ sudo systemctl restart systemd-networkd
你可以用 brctl 工具 来验证是否创建了网桥 br0。 You can use brctl tool to verify that a bridge br0 has been created.
总结
Summary
当 systemd 誓言成为 Linux 的系统管理器时，有类似 systemd-networkd 的东西来管理网络配置也就不足为奇。但是在现阶段，systemd-networkd 看起来更适合于网络配置相对稳定的服务器环境。对于桌面/笔记本环境，它们有多种临时有线/无线接口，NetworkManager 仍然是比较好的选择。 When systemd promises to be a system manager for Linux, it is no wonder something like systemd-networkd came into being to manage network configurations. At this stage, however, systemd-networkd seems more suitable for a server environment where network configurations are relatively stable. For desktop/laptop environments which involve various transient wired/wireless interfaces, NetworkManager may still be a preferred choice.
对于想进一步了解 systemd-networkd 的人，可以参考官方man 手册了解完整的支持列表和关键点。 For those who want to check out more on systemd-networkd, refer to the official man page for a complete list of supported sections and keys.
via: http://xmodulo.com/switch-from-networkmanager-to-systemd-networkd.html