KVM Network Bridge Setup

1. 安裝套件
   

   [root@deyu ~]# yum install libvirt bridge-utils
   

2. /etc/init.d/network與/etc/init.d/NetworkManager選擇一樣設定啟動網路
   1. 以/etc/sysconfig/network-scripts/下網卡設定啟動網路
      1. 查看eth0設定
         

         [root@deyu ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
         DEVICE="eth0"
         BOOTPROTO="static"
         DNS1="192.168.0.254"
         HOSTNAME="deyu.example.com"
         HWADDR="48:5B:39:C4:F5:31"
         IPADDR="192.168.0.254"
         MTU="1500"
         NETMASK="255.255.255.0"
         NM_CONTROLLED="yes"
         ONBOOT="yes"
         

      2. 將eth0備份且建立橋接界面br0
         

         [root@deyu ~]# cp /etc/sysconfig/network-scripts/ifcfg-eth0\
          /etc/sysconfig/network-scripts/backup-ifcfg-eth0
         [root@deyu ~]# cp /etc/sysconfig/network-scripts/ifcfg-eth0\
          /etc/sysconfig/network-scripts/backup-ifcfg-br0
         

      3. 修改eth0成如下：
         

         DEVICE="eth0"
         ONBOOT="yes"
         BRIDGE=br0
         

      4. 修改br0成如下：
         

         DEVICE="br0"
         BOOTPROTO="static"
         IPADDR="192.168.0.254"
         GATEWAY=192.168.0.254
         NETMASK="255.255.255.0"
         DNS1="192.168.0.254"
         HOSTNAME="deyu.example.com"
         NAME="Bridge eth0"
         ONBOOT="yes"
         TYPE="Bridge"
         

      5. 重新啟動網路
         

         [root@deyu ~]# /etc/init.d/network restart
         

   2. 以NetworkManager管理
      1. 查看eth0設定
         

         DEVICE="eth0"
         NM_CONTROLLED="yes"
         BOOTPROTO="none"
         ONBOOT="yes"
         

      2. 修改virbr0設定
         

         [root@rhcsa ~]# vim /usr/share/libvirt/networks/default.xml
         <network>
           <name>default</name>
           <bridge name="virbr0" />
           <forward/>
           <ip address="192.168.122.1" netmask="255.255.255.0">
             <dhcp>
               <range start="192.168.122.2" end="192.168.122.9" />
             </dhcp>
           </ip>
         </network>
         

   3. 重新啟動網路
      

      [root@rhcsa ~]# /etc/init.d/NetworkManager restart
      

3. 虛擬機以dhcp重新啟動網路，看ip是否在設定的範圍內？
   

   [root@kvm2 ~]# /etc/init.d/network restart
   [root@kvm2 ~]# ifconfig
   

4. 虛擬機要連上外部網路
   

   [root@deyu ~]# vim /etc/sysctl.conf
   net.ipv4.ip_forward = 1
   [root@deyu ~]# sysctl -p
   [root@deyu ~]# iptables -t nat -A POSTROUTING -o virbr0 -j MASQUERADE