Centos 7 – bridge for KVM
I got a machine on which I wanted to try Centos 7 and KVM virtualization. As usual, I had to search for how to do a network bridge as it’s been quite long since I did it last time (on Centos 6). So these are the basic steps. First, dont’t forget to install bridge-utils while installing the KVM-related packages:
yum install qemu-kvm libvirt virt-install bridge-utils ifconfig bind-utils
Now, this was the default config file for the network interface:
# cat /etc/sysconfig/network-scripts/ifcfg-enp3s1 TYPE=Ethernet BOOTPROTO=dhcp DEFROUTE=yes PEERDNS=yes PEERROUTES=yes IPV4_FAILURE_FATAL=no IPV6INIT=yes IPV6_AUTOCONF=yes IPV6_DEFROUTE=yes IPV6_PEERDNS=yes IPV6_PEERROUTES=yes IPV6_FAILURE_FATAL=no NAME=enp3s1 UUID=5435015d-7174-414a-9fa3-9b5ec715a054 DEVICE=enp3s1 ONBOOT=yes
I had to change it to point to a bridge interface called bridge0.
# cat /etc/sysconfig/network-scripts/ifcfg-enp3s1 DEVICE="enp3s1" ONBOOT="yes" NM_CONTROLLED="no" #TYPE=Ethernet BRIDGE=bridge0 BOOTPROTO=static
And this is where the new network configuration goes. It’s probably worth mentioning that it’s been changed from DHPC to a static IP address:
# cat /etc/sysconfig/network-scripts/ifcfg-bridge0 DEVICE="bridge0" ONBOOT="yes" TYPE=Bridge BOOTPROTO=static IPADDR=192.168.0.103 NETMASK=255.255.255.0
and also that the GATEWAY has been moved to /etc/sysconfig/network.
# cat /etc/sysconfig/network # Created by anaconda GATEWAY=192.168.2.1
service network restart
you should be able to connect KVM VMs directly to the LAN.