NMState：一个声明式网络配置工具

频道：行业资讯日期：2023-03-27 01:22:28 浏览：930

这篇文章描述并演示了 NMState，这是一个使用声明式方法配置主机的网络管理器。这意味着你可以通过 API 定义所需的配置状态，而工具则通过提供者provider来应用配置。

配置方法：命令式与声明式

网络管理有时候是一项非常复杂的任务，这取决于环境的规模和多样性。在 IT 的早期，网络管理依赖于网络管理员在网络设备上手动执行命令。如今，基础设施即代码Infrastructure as Code（IaC）允许以不同的方式将这些任务自动化。z这基本上有两种方法：命令式或声明式。

在命令式方法中，你会定义“如何”达到所需的配置状态。而在声明式范式里则定义了“什么”是所需的配置状态，所以它不确定哪些步骤是必需的，也不确定它们必须以何种顺序执行。这种方法目前正在聚集更多的人员参与，你可以在目前使用的大多数管理和编排工具上找到它。

NMState：一个声明式的工具

NMState 是一个网络管理器，允许你按照声明式方法配置主机。这意味着你通过一个北向的声明式 API 定义所需的配置状态，这个工具通过南向的提供者provider应用配置。

目前 NMState 支持的唯一的提供者是 NetworkManager，它是为 Fedora Linux 提供网络功能的主要服务。不过，NMState 的开发计划中将逐渐增加其他提供者。

关于 NMState 的进一步信息，请访问其项目站点或 GitHub仓库。

安装

NMState 在 Fedora Linux 29+ 上可用，需要在系统上安装并运行 NetworkManager 1.26 或更高版本。下面是在 Fedora Linux 34 上的安装情况：

$ sudo dnf -y install nmstate ... 输出节略 ... Installed: NetworkManager-config-server-1:1.30.4-1.fc34.noarch gobject-introspection-1.68.0-3.fc34.x86_64 nispor-1.0.1-2.fc34.x86_64 nmstate-1.0.3-2.fc34.noarch python3-gobject-base-3.40.1-1.fc34.x86_64 python3-libnmstate-1.0.3-2.fc34.noarch python3-nispor-1.0.1-2.fc34.noarch python3-varlink-30.3.1-2.fc34.noarch Complete!

这样，你可以使用 nmstatectl作为 NMState 的命令行工具。请参考nmstatectl -help或man nmstatectl以了解关于这个工具的进一步信息。

使用 NMstate

首先要检查系统中安装的 NMState 版本：

$ nmstatectl version 1.0.3

检查一个网络接口的当前配置，例如 eth0的配置：

$ nmstatectl show eth0 2021-06-29 10:28:21,530 root DEBUG NetworkManager version 1.30.4 2021-06-29 10:28:21,531 root DEBUG Async action: Retrieve applied config: ethernet eth0 started 2021-06-29 10:28:21,531 root DEBUG Async action: Retrieve applied config: ethernet eth1 started 2021-06-29 10:28:21,532 root DEBUG Async action: Retrieve applied config: ethernet eth0 finished 2021-06-29 10:28:21,533 root DEBUG Async action: Retrieve applied config: ethernet eth1 finished --- dns-resolver: config: {} running: search: server: - 192.168.122.1 route-rules: config: routes: config: running: - destination: fe80::/64 metric: 100 next-hop-address: next-hop-interface: eth0 table-id: 254 - destination: 0.0.0.0/0 metric: 100 next-hop-address: 192.168.122.1 next-hop-interface: eth0 table-id: 254 - destination: 192.168.122.0/24 metric: 100 next-hop-address: next-hop-interface: eth0 table-id: 254 interfaces: - name: eth0 type: ethernet state: up ipv4: enabled: true address: - ip: 192.168.122.238 prefix-length: 24 auto-dns: true auto-gateway: true auto-route-table-id: 0 auto-routes: true dhcp: true ipv6: enabled: true address: - ip: fe80::c3c9:c4f9:75b1:a570 prefix-length: 64 auto-dns: true auto-gateway: true auto-route-table-id: 0 auto-routes: true autoconf: true dhcp: true lldp: enabled: false mac-address: 52:54:00:91:E4:4E mtu: 1500

正如你在上面看到的，这个网络配置显示了四个主要部分：

dns-resolver：这部分是这个接口的名字服务器配置。route-rules：它说明了路由规则。routes：它包括动态和静态路由。interfaces：这部分描述了 ipv4 和 ipv6 设置。

修改配置

你可以在两种模式下修改所需的配置状态：

交互式：通过 nmstatectl edit编辑接口配置。这个命令调用环境变量EDITOR定义的文本编辑器，因此可以用 yaml 格式编辑网络状态。完成编辑后，NMState 将应用新的网络配置，除非有语法错误。基于文件的：使用 nmstatectl apply应用接口配置，它从先前创建的 yaml 或 json 文件中导入一个所需的配置状态。

下面几节告诉你如何使用 NMState 来改变网络配置。这些改变可能会对系统造成破坏，所以建议在测试系统或客户虚拟机上执行这些任务，直到你对 NMState 有更好的理解。

这里使用的测试系统有两个以太网接口，eth0和eth1：

$ ip -br -4 a lo UNKNOWN 127.0.0.1/8 eth0 UP 192.168.122.238/24 eth1 UP 192.168.122.108/24 互动配置模式的例子

使用 nmstatectl edit命令将eth0接口的 MTU 改为 9000 字节，如下所示：

$ sudo nmstatectl edit eth0 --- dns-resolver: config: {} running: search: server: - 192.168.122.1 route-rules: config: routes: config: running: - destination: fe80::/64 metric: 100 next-hop-address: next-hop-interface: eth0 table-id: 254 - destination: 0.0.0.0/0 metric: 100 next-hop-address: 192.168.122.1 next-hop-interface: eth0 table-id: 254 - destination: 192.168.122.0/24 metric: 100 next-hop-address: next-hop-interface: eth0 table-id: 254 interfaces: - name: eth0 type: ethernet state: up ipv4: enabled: true address: - ip: 192.168.122.123 prefix-length: 24 auto-dns: true auto-gateway: true auto-route-table-id: 0 auto-routes: true dhcp: true ipv6: enabled: true address: - ip: fe80::c3c9:c4f9:75b1:a570 prefix-length: 64 auto-dns: true auto-gateway: true auto-route-table-id: 0 auto-routes: true autoconf: true dhcp: true lldp: enabled: false mac-address: 52:54:00:91:E4:4E mtu: 9000

在保存并退出编辑器后，NMState 应用新的网络期望状态：

2021-06-29 11:29:05,726 root DEBUG Nmstate version: 1.0.3 2021-06-29 11:29:05,726 root DEBUG Applying desire state: {dns-resolver: {config: {}, running: {search: , server: [192.168.122.1]}}, route-rules: {config: }, routes: {config: , running: [{destination: fe80::/64, metric: 102, next-hop-address: , next-hop-interface: eth0, table-id: 254}, {destination: 0.0.0.0/0, metric: 102, next-hop-address: 192.168.122.1, next-hop-interface: eth0, table-id: 254}, {destination: 192.168.122.0/24, metric: 102, next-hop-address: , next-hop-interface: eth0, table-id: 254}]}, interfaces: [{name: eth0, type: ethernet, state: up, ipv4: {enabled: True, address: [{ip: 192.168.122.238, prefix-length: 24}], auto-dns: True, auto-gateway: True, auto-route-table-id: 0, auto-routes: True, dhcp: True}, ipv6: {enabled: True, address: [{ip: fe80::5054:ff:fe91:e44e, prefix-length: 64}], auto-dns: True, auto-gateway: True, auto-route-table-id: 0, auto-routes: True, autoconf: True, dhcp: True}, lldp: {enabled: False}, mac-address: 52:54:00:91:E4:4E, mtu: 9000}]} --- output omitted --- 2021-06-29 11:29:05,760 root DEBUG Async action: Update profile uuid:2bdee700-f62b-365a-bd1d-69d9c31a9f0c iface:eth0 type:ethernet started 2021-06-29 11:29:05,792 root DEBUG Async action: Update profile uuid:2bdee700-f62b-365a-bd1d-69d9c31a9f0c iface:eth0 type:ethernet finished

现在，使用 ip命令和eth0的配置文件来检查eth0的MTU是不是 9000 字节。

$ ip link show eth0 2: eth0: 基于文件的配置模式的例子

让我们使用基于文件的方法来设置一个新的配置状态。这里我们禁用 eth1接口的 IPv6 配置。

首先，创建一个 yaml 文件来定义 eth1接口的期望状态。使用nmstatectl show来保存当前设置，然后使用nmstatectl edit来禁用 IPv6。

$ nmstatectl show eth1 > eth1.yaml $ vi eth1.yaml --- dns-resolver: config: {} running: search: server: - 192.168.122.1 route-rules: config: routes: config: running: - destination: fe80::/64 metric: 101 next-hop-address: next-hop-interface: eth1 table-id: 254 - destination: 0.0.0.0/0 metric: 101 next-hop-address: 192.168.122.1 next-hop-interface: eth1 table-id: 254 - destination: 192.168.122.0/24 metric: 101 next-hop-address: next-hop-interface: eth1 table-id: 254 interfaces: - name: eth1 type: ethernet state: up ipv4: enabled: true address: - ip: 192.168.122.108 prefix-length: 24 auto-dns: true auto-gateway: true auto-route-table-id: 0 auto-routes: true dhcp: true ipv6: enabled: false address: - ip: fe80::5054:ff:fe3c:9b04 prefix-length: 64 auto-dns: true auto-gateway: true auto-route-table-id: 0 auto-routes: true autoconf: true dhcp: true lldp: enabled: false mac-address: 52:54:00:3C:9B:04 mtu: 1500

保存新的配置后，用它来应用新的状态：

$ sudo nmstatectl apply eth1.yaml 2021-06-29 12:17:21,531 root DEBUG Nmstate version: 1.0.3 2021-06-29 12:17:21,531 root DEBUG Applying desire state: {dns-resolver: {config: {}, running: {search: , server: [192.168.122.1]}}, route-rules: {config: }, routes: {config: , running: [{destination: fe80::/64, metric: 101, next-hop-address: , next-hop-interface: eth1, table-id: 254}, {destination: 0.0.0.0/0, metric: 101, next-hop-address: 192.168.122.1, next-hop-interface: eth1, table-id: 254}, {destination: 192.168.122.0/24, metric: 101, next-hop-address: , next-hop-interface: eth1, table-id: 254}]}, interfaces: [{name: eth1, type: ethernet, state: up, ipv4: {enabled: True, address: [{ip: 192.168.122.108, prefix-length: 24}], auto-dns: True, auto-gateway: True, auto-route-table-id: 0, auto-routes: True, dhcp: True}, ipv6: {enabled: False}, lldp: {enabled: False}, mac-address: 52:54:00:3C:9B:04, mtu: 1500}]} --- output omitted --- 2021-06-29 12:17:21,582 root DEBUG Async action: Update profile uuid:5d7244cb-673d-3b88-a675-32e31fad4347 iface:eth1 type:ethernet started 2021-06-29 12:17:21,587 root DEBUG Async action: Update profile uuid:5d7244cb-673d-3b88-a675-32e31fad4347 iface:eth1 type:ethernet finished --- output omitted --- Desired state applied: --- dns-resolver: config: {} running: search: server: - 192.168.122.1 route-rules: config: routes: config: running: - destination: fe80::/64 metric: 101 next-hop-address: next-hop-interface: eth1 table-id: 254 - destination: 0.0.0.0/0 metric: 101 next-hop-address: 192.168.122.1 next-hop-interface: eth1 table-id: 254 - destination: 192.168.122.0/24 metric: 101 next-hop-address: next-hop-interface: eth1 table-id: 254 interfaces: - name: eth1 type: ethernet state: up ipv4: enabled: true address: - ip: 192.168.122.108 prefix-length: 24 auto-dns: true auto-gateway: true auto-route-table-id: 0 auto-routes: true dhcp: true ipv6: enabled: false lldp: enabled: false mac-address: 52:54:00:3C:9B:04 mtu: 1500

你可以检查看到 eth1接口没有配置任何 IPv6：

$ ip -br a lo UNKNOWN 127.0.0.1/8 ::1/128 eth0 UP 192.168.122.238/24 fe80::5054:ff:fe91:e44e/64 eth1 UP 192.168.122.108/24 $ sudo cat /etc/NetworkManager/system-connections/eth1.nmconnection [connection] id=eth1 uuid=5d7244cb-673d-3b88-a675-32e31fad4347 type=ethernet interface-name=eth1 lldp=0 permissions= [ethernet] cloned-mac-address=52:54:00:3C:9B:04 mac-address-blacklist= mtu=1500 [ipv4] dhcp-client-id=mac dhcp-timeout=2147483647 dns-search= method=auto [ipv6] addr-gen-mode=eui64 dhcp-duid=ll dhcp-iaid=mac dns-search= method=disabled [proxy] 临时应用改变

NMState 的一个有趣的功能允许你临时配置一个期望的网络状态。如果你对这个配置感到满意，你可以事后提交。否则，当超时（默认为 60 秒）过后，它将回滚。

修改前面例子中的 eth1配置，使它有一个 IPv4 静态地址，而不是通过 DHCP 动态获得。

$ vi eth1.yaml --- dns-resolver: config: {} running: search: server: - 192.168.122.1 route-rules: config: routes: config: running: - destination: fe80::/64 metric: 101 next-hop-address: next-hop-interface: eth1 table-id: 254 - destination: 0.0.0.0/0 metric: 101 next-hop-address: 192.168.122.1 next-hop-interface: eth1 table-id: 254 - destination: 192.168.122.0/24 metric: 101 next-hop-address: next-hop-interface: eth1 table-id: 254 interfaces: - name: eth1 type: ethernet state: up ipv4: enabled: true address: - ip: 192.168.122.110 prefix-length: 24 auto-dns: true auto-gateway: true auto-route-table-id: 0 auto-routes: true dhcp: false ipv6: enabled: false lldp: enabled: false mac-address: 52:54:00:3C:9B:04 mtu: 1500

现在，使用选项 no-commit临时应用这个配置，让它只在 30 秒内有效。这可以通过添加选项timeout来完成。同时，我们将运行ip -br a命令三次，看看配置在eth1接口的 IPv4 地址是如何变化的，然后配置就会回滚。

$ ip -br a && sudo nmstatectl apply --no-commit --timeout 30 eth1.yaml && sleep 10 && ip -br a && sleep 25 && ip -br a lo UNKNOWN 127.0.0.1/8 ::1/128 eth0 UP 192.168.122.238/24 fe80::5054:ff:fe91:e44e/64 eth1 UP 192.168.122.108/24 2021-06-29 17:29:18,266 root DEBUG Nmstate version: 1.0.3 2021-06-29 17:29:18,267 root DEBUG Applying desire state: {dns-resolver: {config: {}, running: {search: , server: [192.168.122.1]}}, route-rules: {config: }, routes: {config: , running: [{destination: fe80::/64, metric: 101, next-hop-address: , next-hop-interface: eth1, table-id: 254}, {destination: 0.0.0.0/0, metric: 101, next-hop-address: 192.168.122.1, next-hop-interface: eth1, table-id: 254}, {destination: 192.168.122.0/24, metric: 101, next-hop-address: , next-hop-interface: eth1, table-id: 254}]}, interfaces: [{name: eth1, type: ethernet, state: up, ipv4: {enabled: True, address: [{ip: 192.168.122.110, prefix-length: 24}], dhcp: False}, ipv6: {enabled: False}, lldp: {enabled: False}, mac-address: 52:54:00:3C:9B:04, mtu: 1500}]} --- output omitted --- Desired state applied: --- dns-resolver: config: {} running: search: server: - 192.168.122.1 route-rules: config: routes: config: running: - destination: fe80::/64 metric: 101 next-hop-address: next-hop-interface: eth1 table-id: 254 - destination: 0.0.0.0/0 metric: 101 next-hop-address: 192.168.122.1 next-hop-interface: eth1 table-id: 254 - destination: 192.168.122.0/24 metric: 101 next-hop-address: next-hop-interface: eth1 table-id: 254 interfaces: - name: eth1 type: ethernet state: up ipv4: enabled: true address: - ip: 192.168.122.110 prefix-length: 24 dhcp: false ipv6: enabled: false lldp: enabled: false mac-address: 52:54:00:3C:9B:04 mtu: 1500 Checkpoint: NetworkManager|/org/freedesktop/NetworkManager/Checkpoint/7 lo UNKNOWN 127.0.0.1/8 ::1/128 eth0 UP 192.168.122.238/24 fe80::5054:ff:fe91:e44e/64 eth1 UP 192.168.122.110/24 lo UNKNOWN 127.0.0.1/8 ::1/128 eth0 UP 192.168.122.238/24 fe80::5054:ff:fe91:e44e/64 eth1 UP 192.168.122.108/24

从上面可以看到，eth1的 IP 地址从192.168.122.108暂时变成了192.168.122.110，然后在超时结束后又回到了192.168.122.108。