virsh list报错： error: failed to connect to the hypervisor

查看本地kvm虚机时，发现无法查看，出现报错

# virsh list
error: failed to connect to the hypervisor
error: Failed to connect socket to '/var/run/libvirt/libvirt-sock': Connection refused

由报错可发现是 libvirt异常，查看对应的libvirtd服务，发现服务未启动，然后直接启服务

如果存在服务启动异常，则针对对应的服务找问题即可，如依赖包版本问题

可尝试如下命令刷新依赖包

#yum -y remove qemu-kvm libvirt libguestfs-tools virt-install  virt-manager xorg-x11-xauth&&yum -y install qemu-kvm libvirt libguestfs-tools virt-install  virt-manager xorg-x11-xauth

[root@controller1 ~]# virsh list
error: failed to connect to the hypervisor
error: Failed to connect socket to '/var/run/libvirt/libvirt-sock': Connection refused

[root@controller1 ~]# systemctl status libvirtd
● libvirtd.service - Virtualization daemon
   Loaded: loaded (/usr/lib/systemd/system/libvirtd.service; enabled; vendor preset: enabled)
   Active: inactive (dead) since Mon 2022-12-05 12:03:12 CST; 1h 39min ago
     Docs: man:libvirtd(8)
           https://libvirt.org
 Main PID: 4409 (code=exited, status=0/SUCCESS)
   CGroup: /system.slice/libvirtd.service
           ├─1838 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/libexec/libvirt_leaseshelper
           └─1839 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/libexec/libvirt_leaseshelper

Dec 02 17:49:37 controller1 dnsmasq[1838]: read /etc/hosts - 5 addresses
Dec 02 17:49:37 controller1 dnsmasq[1838]: read /var/lib/libvirt/dnsmasq/default.addnhosts - 0 addresses
Dec 02 17:49:37 controller1 dnsmasq-dhcp[1838]: read /var/lib/libvirt/dnsmasq/default.hostsfile
Dec 02 17:49:55 controller1 libvirtd[4409]: libvirt version: 7.6.0, package: 6.el8 (CBS <cbs@centos.org>, 2021-11-17-01:57:30, )
Dec 02 17:49:55 controller1 libvirtd[4409]: hostname: controller1
Dec 02 17:49:55 controller1 libvirtd[4409]: operation failed: pool 'default' already exists with uuid 7ceb85c9-2688-40dc-adb4-2aafa92d59c3
Dec 02 21:33:10 controller1 libvirtd[4409]: internal error: End of file from qemu monitor
Dec 05 12:03:07 controller1 systemd[1]: Stopping Virtualization daemon...
Dec 05 12:03:12 controller1 systemd[1]: libvirtd.service: Succeeded.
Dec 05 12:03:12 controller1 systemd[1]: Stopped Virtualization daemon.
[root@controller1 ~]# systemctl start libvirtd
[root@controller1 ~]# virsh list
 Id   Name             State
--------------------------------
 5    centos-stream8   running