Setting Up Linux LXC Virtualization

LXC virtualization is included in the 2.6.29 Linux kernel, so many recent distributions support it without the need to install a custom kernel. In particular Debian Squeeze and Ubuntu 10 and later include an LXC-capable kernel and tools.

LXC is a kernel-level virtualization type, in which each virtual system's files are stored under a directory on the host system, typically under /var/lib/lxc . All virtual systems share the same kernel with the host and each other, which reduces per-system overhead.

For LXC containers to access the host system's network, you must setup a network bridge. These instructions assume that your host system has only one network interface, and it is eth0 .

Setting up a Fedora Host System

To setup a Fedora 12 or later system to host KVM instances, the steps to follow are :

1. SSH in as root and install the LXC packages with the command yum install lxc bridge-utils
2. In the /etc/sysconfig/network-scripts directory, copy ifcfg-eth0 to ifcfg-br0.
3. Edit the new file and change the DEVICE line to DEVICE=br0.
4. Edit the ifcfg-eth0 file, and at the bottom add the line BRIDGE=br0
5. Apply the network settings with the command service network restart . This should be done at the console, as it will break network access to the host system if anything goes wrong.

Setting up a Debian or Ubuntu Host System

1. SSH in as root and install the LXC packages with the command apt-get lxc bridge-utils
2. Edit the /etc/network/interfaces file and change it to be like :

   auto eth0 lo br0
    
   iface lo inet loopback
    
   iface eth0 inet manual
    
   iface br0 inet static
      address 192.168.1.1
      netmask 255.255.255.0
      broadcast 192.168.1.255
      network 192.168.1.0
      gateway 192.168.1.10
      bridge_ports eth0
      bridge_fd 9
      bridge_hello 2
      bridge_maxage 12
      bridge_stp off

3. Apply the network settings with the command /etc/init.d/networking restart or by rebooting . This should be done at the console, as it will break network access to the host system if anything goes wrong.

Adding a New Host System

1. Install Webmin on the host system, if it isn't already.
2. Add the host system to Cloudmin at Add System -> Add physical system, if it isn't already.
3. Go to Host Systems -> LXC Host Systems, click the Register a system for LXC hosting link and select your new host machine.
4. Enter an IP range to allocate to virtual systems, and a DNS domain to add new systems to.
5. Click the Register button.