KVM网络如何设置DHCP

缺省情况下kvm会保留一个nat的网络，ip a命令查看，会看到virbr0和virbr0-nic

8: virbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN 
   link/ether 52:54:00:6c:22:2c brd ff:ff:ff:ff:ff:ff
   inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
9: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 500
   link/ether 52:54:00:6c:22:2c brd ff:ff:ff:ff:ff:ff

这个如果虚机都是静态IP，且不做NAT的话，则无必要保留，可以彻底删掉。

kvm删除掉缺省网络

virsh net-destroy default
virsh net-undefine default

那么如果非用不可，还需要给特定虚机用dhcp指定固定IP 方法如下：

查看缺省网络

$ virsh net-list
 Name                 State      Autostart     Persistent
----------------------------------------------------------
 default              active     yes           yes

找出虚机的mac地址

$ virsh dumpxml vis-16-10-33 | grep -i '<mac'
  <mac address='f0:00:ac:10:0a:21'/>

编辑网络

$ virsh net-edit default

<network>
  <name>default</name>
  <uuid>58e86841-ef4b-4d63-bf4f-7888515b8474</uuid>
  <forward mode='nat'/>
  <bridge name='virbr0' stp='on' delay='0' />
  <mac address='52:54:00:6C:22:2C'/>
  <ip address='192.168.122.1' netmask='255.255.255.0'>
    <dhcp>
      <range start='192.168.122.2' end='192.168.122.254' />
    </dhcp>
  </ip>
</network>

在range下面来一列

    <dhcp>
      <range start='192.168.122.2' end='192.168.122.254' />
	  <host mac='f0:00:ac:10:0a:21' name='vis-16-10-33' ip='192.168.122.10'/>
    </dhcp>

保存退出，重启网络

$ virsh net-destroy default
$ virsh net-start default

然后就可以了。