networkctl¶

networkctl是一个命令行检查网络设备和连接状态的命令行工具，可以用来查询或者控制Linux网络子系统。这是在systemd中引入的新命令。

在运行 networkctl 之前，需要确保 systemd-networkd 服务已经运行，否则会出现错误:

WARNING: systemd-networkd is not running, output will be incomplete.

如果没有启动systemd-networkd，则通过以下命令启动和激活:

sudo systemctl start systemd-networkd
sudo systemctlenable systemd-networkd

检查所有网络链接和设备额状态:
```
networkctl
```

输出显示:

IDX LINK  TYPE     OPERATIONAL SETUP
lo    loopback carrier     unmanaged
eth0  ether    routable    configured
wlan0 wlan     no-carrier  configuring

可以通过 networkctl 的 status 命令来查看指定连接的类型，状态，内核模块，硬件和IP地址，配置DNS等等。如果没有指定特定连接，则默认只显示可路由连接。

networkctl status

输出显示:

●   State: routable
  Address: 192.168.6.15 on eth0
           fe80::dea6:32ff:fec5:489c on eth0
  Gateway: 192.168.6.9 (Wistron Infocomm (Zhongshan) Corporation) on eth0
      DNS: 30.11.17.1
           30.17.16.1
           30.17.16.2

Nov 03 21:47:04 pi-worker1 systemd-networkd[1600]: wlan0: Link DOWN
Nov 03 21:47:04 pi-worker1 systemd[1]: Started Network Service.
Nov 03 21:47:04 pi-worker1 systemd-networkd[1600]: wlan0: Link UP
Nov 03 21:47:04 pi-worker1 systemd[1]: Starting Wait for Network to be Configured...
Nov 03 21:47:04 pi-worker1 systemd-networkd[1600]: wlan0: IPv6 successfully enabled
Nov 03 21:47:05 pi-worker1 systemd-networkd[1600]: eth0: IPv6 successfully enabled
Nov 03 21:47:05 pi-worker1 systemd-networkd[1600]: eth0: Link UP
Nov 03 21:47:05 pi-worker1 systemd[1]: Finished Wait for Network to be Configured.
Nov 03 21:47:10 pi-worker1 systemd-networkd[1600]: eth0: Gained carrier
Nov 03 21:47:11 pi-worker1 systemd-networkd[1600]: eth0: Gained IPv6LL

检查链路层发现协议(LLDP, Link Diecovery Discovery Protocol)，则使用 lldp 命令””

networkctl lldp

systemd-networkd的debug日志¶

要排查 systemd-networkd 问题，可以配置该服务开启日志debug，编辑 /etc/systemd/system/systemd-networkd.service.d/override.conf

[Service]
Environment=SYSTEMD_LOG_LEVEL=debug

然后执行journalctl 的 -u 参数指定服务单元，并加上 -f 进行tail:

journalctl -u systemd-networkd.service -f

networkctl¶

systemd-networkd的debug日志¶

参考¶