centos7虚拟机无法开启网络的解决方案

问题

新增问题：

Job for network.service failed because the control process exited with error code. See “systemctl status network.service” and “journalctl -xe” for details.

centos7 突然无法连接网络，使用命令service start network 启动失败
错误信息：
Connection activation failed: No suitable device found for this connection (device lo not available because device is strictly unmanaged)

[croot@root ~]$ systemctl -l  status network
● network.service - LSB: Bring up/down networking
   Loaded: loaded (/etc/rc.d/init.d/network; bad; vendor preset: disabled)
   Active: failed (Result: exit-code) since Thu 2021-06-17 23:19:53 CST; 5min ago
     Docs: man:systemd-sysv-generator(8)
  Process: 841 ExecStart=/etc/rc.d/init.d/network start (code=exited, status=1/FAILURE)

Jun 17 23:19:53 root systemd[1]: Starting LSB: Bring up/down networking...
Jun 17 23:19:53 chenglj network[841]: Bringing up loopback interface:  [  OK  ]
Jun 17 23:19:53 chenglj network[841]: Bringing up interface ens33:  Error: Connection activation failed: No suitable device found for this connection (device lo not available because device is strictly unmanaged).
Jun 17 23:19:53 chenglj network[841]: [FAILED]
Jun 17 23:19:53 chenglj systemd[1]: network.service: control process exited, code=exited status=1
Jun 17 23:19:53 chenglj systemd[1]: Failed to start LSB: Bring up/down networking.
Jun 17 23:19:53 chenglj systemd[1]: Unit network.service entered failed state.
Jun 17 23:19:53 chenglj systemd[1]: network.service failed.

检查

service NetworkManager status

解决

# 临时关闭
systemctl stop NetworkManager 
#永久关闭
systemctl disable NetworkManager  

#再次启动网络服务
systemctl start network