Virtualization (LXC Containers)
As of Fall 2009, we use Linux containers to maintain a few virtual machines, most notably caffeine, which is hosted on glomag. The various commands to manipulate Linux containers are prefixed with "lxc-"; see their individual manpages for usage.
To manage containers, use the lxc-* tools, which require root privilege. Some examples (replace caffeine with the appropriate container name):
# check if caffeine is running lxc-info -n caffeine # start caffeine in the background lxc-start -d -n caffeine # stop caffeine gracefully lxc-halt -n caffeine # stop caffeine forcefully lxc-stop -n caffeine # launch a TTY console for the container lxc-console -n caffeine
To install Linux container support on a recent Debian (squeeze or newer) system:
- Install the lxc and bridge-utils packages.
- Create a bridged network interface (this can be configured in /etc/network/interfaces as though it were a normal Ethernet device, with the additional bridge_ports parameter. This is usually called br0 (can be created manually with brctl). LXC will create a virtual Ethernet device and add it to the bridge when each container starts.
To start caffeine, run the following command as root on glomag:
lxc-start -d -n caffeine
Containers are stored on the host filesystem in /var/lib/lxc (root filesystems are symlinked to the appropriate directory on /vm).
vserver $NAME build -m debootstrap --hostname magic --interface $IFACE:$IP/24 -- -d lenny
To have a vserver autostart, create a file called /etc/vservers/$VSERVER/apps/init/mark with content: