KVM Migrate Error And Solution

ERROR1：

背景：虚拟机的镜像文件放在nfs服务器的共享文件夹中，源主机将共享目录挂载到本机的/mnt/nfs文件夹中，镜像文件为vdisk.img，当源主机启动虚拟机时报如下错误：

[root@qinshang mnt]# virsh start vdisk
error: Failed to start domain vdisk
error: 内部错误 Process exited while reading console log output: char device redirected to /dev/pts/1
qemu-system-x86_64: -drive file=/mnt/nfs/vdisk.img,if=none,id=drive-ide0-0-0,format=qcow2: could not open disk image /mnt/nfs/vdisk.img: Permission denied

Analytics:

SELinux is preventing /usr/bin/qemu-system-x86_64 from open access on the file /mnt/nfs/vdisk.img.

Soution:

If you want to allow confined virtual guests to manage nfs files.Then you must tell SELinux about this by enabling the 'virt_use_nfs' boolean.You can read 'virt_selinux' man page for more details.
Do
setsebool -P virt_use_nfs 1

If you believe that qemu-system-x86_64 should be allowed open access on the vdisk.img file by default.
Then you should report this as a bug.You can generate a local policy module to allow this access.
Do  allow this access for now by executing:

grep qemu-system-x86 /var/log/audit/audit.log | audit2allow -M mypol

semodule -i mypol.pp

ERROR2：

背景：有时候查看挂载nfs共享文件的目录的时候，会出现 stale file handle错误，错误原因这里就不解释了,有兴趣的话，可以访问以下网址：

Solution2：

先用umount -f /mnt/nfs/命令，如果还不奏效的话，再用umount -l /mnt/nfs/命令，如果依然不奏效的话，多敲几下这些命令，再不行的话，关掉nfs服务器，然后重新启动，接着再重新挂载即可解决！

ERROR3：

背景：运行virsh start centos(此处为具体的虚拟机名字)时候，会出现以下错误

error: Failed to reconnect to the hypervisor

error: no valid connection

error: Failed to connect socket to '/usr/local/var/run/libvirt/libvirt-sock': No such file or directory

Solution3:
ln -s /var/run/libvirt/libvirt-sock /usr/local/var/run/libvirt/libvirt-sock

ERROR4:

背景：运行virsh命令的时候，显示以下错误

error: failed to connect to the hypervisor
error: no valid connection
error: Failed to connect socket to '/usr/local/var/run/libvirt/libvirt-sock': Connection refused

分析：

ibvirtd is not running, or running but waiting on '/var/run/libvirt/libvirt-sock' where your virsh is try to look up
'/usr/local/var/run/libvirt/libvirt-sock'

Solution4:

先运行libvirtd -d ， 如果virsh命令能用的话，说明libvirtd已经启动，如果这时候打开virtual manager来管理虚拟机报错的话，再运行命令 systemctl restart libvirtd.service 即可解决！

这时候运行 ps aux | grep libvirtd 查看libvirtd进程的时候可以看到以下结果

暂时先到这，有发现新的问题会再补充