kvm报以下错误：
Unable to connect to libvirt qemu:///system.
确定 ‘libvirtd’ 守护进程正在运行。
Libvirt URI is: qemu:///system
Traceback (most recent call last):
File "/usr/share/virt-manager/virtManager/connection.py", line 1036, in _do_open
self._backend.open(self._do_creds_password)
File "/usr/share/virt-manager/virtinst/connection.py", line 144, in open
open_flags)
File "/usr/lib/python2.7/dist-packages/libvirt.py", line 105, in openAuth
if ret is None:raise libvirtError('virConnectOpenAuth() failed')
libvirtError: Failed to connect socket to '/var/run/libvirt/libvirt-sock': 权限不够
如果说libvirtd服务已经启动了，那么修改/var/run/libvirt/目录下面的libvirt-sock文件权限即可
将原来770的权限改成777即可
chmod 777 libvirt-sock
