centos ve12.05启动vm失败

centos

0.启动vm  clc报没有空闲ip  定时任务  crontab -e        */2 * * * * nmap -sP 172.28.25.2-254

1.etc/libvirt/libvirtd.conf    

unix_sock_group = "libvirt"

unix_sock_ro_perms = "0777"

unix_sock_rw_perms = "0770"

2.etc/libvirt/qemu.conf     group="cloud"     user="cloud"

3.nc启动vm失败的libvir: XML-RPC error : authentication failed: Authorization requires authentication but no agent is available

nc建立libvirt链接授权失败，由于nc没有用sudo 启动