openstack安装libvir报错

libvir 报错信息
2012-08-23 02:50:17.492+0000: 1416: warning : qemuCapsInit:856 : Failed to get host power management capabilities
2012-08-23 02:50:18.422+0000: 1414: error : virExecWithHook:328 : Cannot find 'pm-is-supported' in path: No such file or directory

解决
  sudo apt-get -y install pm-utils
  重启libvir
  /etc/init.d/libvirt-bin restart