centos 7系统网络故障，日志内容：
localhost network: Bringing up interface eth0: Error: Could not create NMClient object: GDBus.Error:org.freedesktop.DBus.Error.UnknownMethod: Method "GetManagedObjects" with signature "" on interface "org.freedesktop.DBus.ObjectManager" doesn't exist
解决方法：
systemctl restart NetworkManager 或者 systemctl stop NetworkManager
然后
systemctl restart network
