KVM Bridge

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Note

Ip address, Netmask and Gateway values used in this guide are dummy values. You will need to replace them with your own network details.

Overview

This guide shows you how to manage the Network Bridge for KVM in Virtualizor.
Virtualizor will create a viifbr0 bridge.
viifbr0 assumes eth0 as the Network Device and detects the IP, Netmask, GATEWAY from :

/etc/sysconfig/network-scripts/ifcfg-eth0

In the event you have a network device (network interface) other thatn eth0, e.g. eth1, then you can configure Virtualizor to use eth1 as the Network interface to create the bridge.

Network Interface

You can change these settings any time from the Virtualizor Admin Panel -> Configuration -> General Settings. The following is a screenshot of the available settings :

KVM Bridge1.jpg

By default eth0 will be assumed as the Network Interface. To tell virtualizor to use anything other than that, please submit it here.

Managing the Bridge

Virtualizor will create a viifbr0 bridge.

Restart Command :

root> service virtnetwork restart

Start Command :

root> service virtnetwork start

Stop Command :

root> service virtnetwork stop


Making the bridge permanent

You can make the bridge a permanent one so that whenever the OS is started, it will start with the bridge as soon as the network is created.
This guide presumes the network interface is eth0 and OS is CentOS.


Backup ifcfg-eth0

The contents of /etc/sysconfig/network-scripts/ifcfg-eth0 will look something like the following :

root# cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
BOOTPROTO=static
TYPE=Ethernet
HWADDR=00:25:90:98:35:90
IPADDR=10.0.0.93
NETMASK=255.255.255.0
GATEWAY=10.0.0.1
IPV6INIT=yes
IPV6ADDR=2607:f0d0:1002:0011:0000:0000:0000:0002
IPV6_DEFAULTGW=2607:f0d0:1002:0011:0000:0000:0000:0001
ONBOOT=yes

Make a copy of it :

root# cp /etc/sysconfig/network-scripts/ifcfg-eth0 /etc/sysconfig/network-scripts/ifcfg-eth0.bak

Create the Bridge File

root# vi /etc/sysconfig/network-scripts/ifcfg-viifbr0

You will need to copy some parts of ifcfg-eth0 to ifcfg-viifbr0 :

DEVICE=viifbr0
TYPE=Bridge
BOOTPROTO=static
IPADDR=105.94.182.93
NETMASK=255.255.255.248
GATEWAY=105.94.182.89
ONBOOT=yes
IPV6INIT=yes
IPV6ADDR=2607:f0d0:1002:0011:0000:0000:0000:0002
IPV6_DEFAULTGW=2607:f0d0:1002:0011:0000:0000:0000:0001

Now save the file.

Edit the ifcfg-eth0 File

root# vi /etc/sysconfig/network-scripts/ifcfg-eth0

It should look like the following :

DEVICE=eth0
HWADDR=00:25:90:98:35:90
IPV6INIT=yes
ONBOOT=yes
BRIDGE=viifbr0

Restart Network

We are almost setup now. Just make sure everything is correct before you restart the network. After that restart the network :

root# service network restart

Note : Virtnetwork will not work anymore and you should restart only with network.


Ubuntu network interface File

root# nano /etc/network/interfaces 

# The loopback network interface
auto lo
iface lo inet loopback

# Bridge for eth0 
auto br0

 iface br0 inet static
  address 192.168.1.10
  netmask 255.255.255.0
  gateway 192.168.1.1
  dns-nameservers 192.168.1.5
   bridge_ports eth0
   bridge_stp off
   bridge_fd 0
   bridge_maxwait 0

bridge_stp off - is a setting for spanning tree. If you have a possibility for network looks, you may want to turn this on.

bridge_fd 0 - turns off all forwarding delay. If you do not know what this is, you probably do not need it.

bridge_maxwait 0 - is how long the system will wait for the Ethernet ports to come up. Zero is no wait.

Restart Network

We are almost setup now. Just make sure everything is correct before you restart the network. After that restart the network :

root# /etc/init.d/networking restart 

Note : Virtnetwork will not work anymore and you should restart only with network.