The Caffeinated Penguin

Posted By matt on February 20, 2010

largely from:
http://lxc.sourceforge.net/lxc.html
https://help.ubuntu.com/community/OpenVZ
http://www.ibm.com/developerworks/linux/library/l-lxc-containers/

With additional notes from:
http://www.stgraber.org/2009/11/06/lxc-containers-or-extremely-fast-virtualization
http://linux-vserver.org/Upstart_issues
http://lxc.teegra.net/

1.) Note that you likely want to create a separate partition for machines and put the machines there.

2.) apt-get install lxc debootstrap
(Note – this is pretty inefficient in terms of space. The lxc setup does allow for read-only mounts of things. So, it can have its own /etc and html docs but share binaries and libraries with the host. But, I didn’t do it that way for ease of backups)

3.) Set up cgroup
mkdir /var/cgroup
mount -t cgroup cgroup /var/cgroup

probably want to add it to /etc/fstab as well:
cgroup /var/cgroup cgroup defaults 0 0

4.) Add a bridged network interface:
brctl addbr br0
brctl setfd br0 0
- bring up the bridge with a given IP
ifconfig br0 promisc up
- add the existing interface and set it to a bad
brctl addif br0 wlan0
ifconfig wlan0 0.0.0.0 up

5.) Bootstrap a basic system
mkdir machine
sudo debootstrap --arch i386 karmic machine

6.) Create a config file:
lxc.utsname = my_ssh_container
lxc.network.type = veth
lxc.network.flags = up
lxc.network.link = br0
lxc.network.ipv4 = 192.168.9.151/24
lxc.network.name = eth0
lxc.mount = /var/lxc-machines/machine/fstab
lxc.rootfs = /var/lxc-machines/machine/rootfs


7.) Create the machine:
lxc-create -n trac -f /var/lxc-machines/machine/config

8.) edit the appropriate files on the guest
/etc/fstab:
none /dev/shm tmpfs defaults 0 0
none /proc proc defaults 0 0
none /dev/pts devpts defaults 0 0
none /sys sysfs defaults 0 0
- /etc/resolv.conf
- /etc/hosts
- /etc/hostname
– Set them up correctly

/etc/init
- remove the following files:
rm control-alt-delete.conf hwclock.conf \
hwclock-save.conf mountall.conf mountall-net.conf \
mountall-reboot.conf mountall-shell.conf \
networking.conf procps.conf rsyslog-kmsg.conf \
tty2.conf tty3.conf tty4.conf tty5.conf \
tty6.conf upstart-udev-bridge.conf

- Create lxc.conf to generate things:
start on startup
script

       >/etc/mtab
       mount -a
       initctl emit virtual-filesystems
       initctl emit local-filesystems
       initctl emit remote-filesystems
       initctl emit filesystem
       ifdown eth0
       ifup eth0

end script

- /etc/apt
grab the sources.list from the host (if guest is same as host) or make one

- /etc/init/rc.sysinit.conf and change the line:
start on filesystem and net-device-up IFACE=lo
to:
start on filesystem
Important: This seems to be fragile in that system updates seem to put it back. If all your machines won’t boot suddenly, check this.

- bootstrap a basic bash so the various nice utilities work:
lxc-start -n trac bash

- add user.
- add admin group
- set sudoers to allow admin group
- add user to admin group
- Generate locale: sudo locale-gen en_US.UTF-8

9.) Start the machine:
lxc-start -n machine init &

Start for real:
lxc-start -n machine

10.) Notes:

Console:
sudo lxc-console -n machine

Debugging:
lxc-start -l DEBUG -o $(tty) --name machine

Category: Computers, Software
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