KVM Bridge

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 -> Slave Settings. The following is a screenshot of the available settings :

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 viifbr0  
iface viifbr0 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.

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