1. The httpd-nc_error.log log shows that the NC process was closed because it could not connect to libvirt
2. View libvirt service, not started
3. Look at the /var/log/libvirt/syslog log. The reason the libvirt service is not started is because loading the configuration file /etc/libvirt/libvirtd.conf failed.
4. Open the configuration file /etc/libvirt/libvirtd.conf with vi and find that there is garbled code, indicating that the configuration file is damaged.
5. This phenomenon is generally caused by a hard disk failure. Score the hard drive and find that multiple hard drives score low
root cause :
A hard disk failure caused the libvirt configuration file to be corrupted and the vnad service could not be started.
