CentOS 配置 DNS

女爷i 2023-02-17 05:12 15阅读 0赞

> 参考：[How to set DNS in CentOS/RHEL 7 & prevent NetworkManager from overwriting /etc/resolv.conf?][How to set DNS in CentOS_RHEL 7 _ prevent NetworkManager from overwriting _etc_resolv.conf]

配置 DNS 时可以直接在网卡上进行配置，例如在 `/etc/sysconfig/network-scripts/eth0` 中添加：

DNS1=x.x.x.1
    DNS2=x.x.x.2
    DNS3=x.x.x.3
    DOMAIN='xxx.com'

网卡有了配置后，NetworkManager 会自动将 DNS 信息写入到 `/etc/resolv.conf` 配置文件中。

如果你手动修改 `/etc/resolv.conf`，你会发现服务器重启后，里面的内容会自动复原，复原的第一行注释为 `# Generated by NetworkManager`，这是因为 NetworkManager 会自动更新这里的配置。

## 手动配置 ##

想要能够手动更新 `/etc/resolv.conf`，需要关闭 NetworkManager 的自动更新功能。

关闭方法，打开 `/etc/NetworkManager/NetworkManager.conf` 在 `[main]` 下面添加`dns=none`，然后 `sudo systemctl restart NetworkManager.service` 重启服务。重启以后就能手工修改了。

## 自动化脚本 ##

为了方便配置所有服务器，下面是一个 ansible 脚本：

`resolve.conf` 配置文件准备好：

search xxx.com
    nameserver x.x.x.1
    nameserver x.x.x.2

playbook 脚本 `dns.yaml`:

- name: update dns
      hosts: 服务器
      vars:
        dns_file: /etc/resolv.conf
      tasks:
       - name: disable dns update
         blockinfile:
           path: /etc/NetworkManager/NetworkManager.conf
           insertafter: "\\[main\\]"
           block: | dns=none
       - name: restart NetworkManager
         service:
           name: NetworkManager
           state: restarted
       - name: copy resolv.conf
         copy: src=resolv.conf dest={ {  dns_file }}

[How to set DNS in CentOS_RHEL 7 _ prevent NetworkManager from overwriting _etc_resolv.conf]: https://wiseindy.com/blog/linux/how-to-set-dns-in-centos-rhel-7-prevent-network-manager-from-overwriting-etc-resolv-conf/