CentOS7 Network Service開機無法啟動的解決方法

CentOS7安裝完成並配置好所有網絡相關配置后重啟機器，使用

$ systemctl --failed

檢查是否有失敗的服務

發現在network服務啟動失敗，使用systemctl status network查看服務狀態，得到如下錯誤信息：

$ systemctl status network

Nov 23 22:09:07 hdcoe02 network[597]: Bringing up loopback interface:  Could not load file '/etc/sysconfig/network-scripts/ifcfg-lo'  
Nov 23 22:09:07 hdcoe02 network[597]: Could not load file '/etc/sysconfig/network-scripts/ifcfg-lo'  
Nov 23 22:09:08 hdcoe02 network[597]: Could not load file '/etc/sysconfig/network-scripts/ifcfg-lo'  
Nov 23 22:09:08 hdcoe02 network[597]: Could not load file '/etc/sysconfig/network-scripts/ifcfg-lo'  
Nov 23 22:09:08 hdcoe02 network[597]: [  OK  ]  
Nov 23 22:09:08 hdcoe02 network[597]: Bringing up interface enp0s25:  Error: Connection activation failed: Connection 'enp0s25' is not available on the device enp0s25 at this time.  
Nov 23 22:09:08 hdcoe02 network[597]: [FAILED]  
Nov 23 22:09:08 hdcoe02 systemd[1]: network.service: control process exited, code=exited status=1  
Nov 23 22:09:08 hdcoe02 systemd[1]: Failed to start LSB: Bring up/down networking.  

設定開機啟動一個名為NetworkManager-wait-online服務，命令為：

$ systemctl enable NetworkManager-wait-online.service

 重啟network:

$ systemctl restart network