Debian Squeeze/Testing LXC container patch

Prepare Debian Squeeze/Testing container

1. Copy the following into file lxc-debian-testing. This is a modified version of /usr/lib/lxc/templates/lxc-debian to get it working with squeeze/testing release of dedian:

   #!/bin/bash
   
   configure_debian()
   {
       rootfs=$1
       hostname=$2
   
       # configure the inittab
       cat <<EOF > $rootfs/etc/inittab
   id:3:initdefault:
   si::sysinit:/etc/init.d/rcS
   l0:0:wait:/etc/init.d/rc 0
   l1:1:wait:/etc/init.d/rc 1
   l2:2:wait:/etc/init.d/rc 2
   l3:3:wait:/etc/init.d/rc 3
   l4:4:wait:/etc/init.d/rc 4
   l5:5:wait:/etc/init.d/rc 5
   l6:6:wait:/etc/init.d/rc 6
   # Normally not reached, but fallthrough in case of emergency.
   z6:6:respawn:/sbin/sulogin
   1:2345:respawn:/sbin/getty 38400 console
   c1:12345:respawn:/sbin/getty 38400 tty1 linux
   c2:12345:respawn:/sbin/getty 38400 tty2 linux
   EOF
    
       # create tty devices
       chroot $rootfs mknod -m 666 /dev/tty1 c 4 1
       chroot $rootfs mknod -m 666 /dev/tty2 c 4 2
   
       # disable selinux in debian
       mkdir -p $rootfs/selinux
       echo 0 > $rootfs/selinux/enforce
   
       # configure the network using the dhcp
       cat <<EOF > $rootfs/etc/network/interfaces
   auto lo
   iface lo inet loopback
   
   auto eth0
   iface eth0 inet dhcp
   EOF
   
       # set the hostname
       cat <<EOF > $rootfs/etc/hostname
   $hostname
   EOF
   
       # set dhcp hostname
       cat <<EOF >> $rootfs/etc/dhcp/dhclient.conf
   send host-name "$hostname";
   EOF
   
       # set default locale
       cat <<EOF > $rootfs/etc/locale.gen
   en_US.UTF-8 UTF-8
   EOF
       
       # reconfigure some services
       if [ -z "$LANG" ]; then
       chroot $rootfs locale-gen en_US.UTF-8
       chroot $rootfs update-locale LANG=en_US.UTF-8
       else
       chroot $rootfs locale-gen $LANG
       chroot $rootfs update-locale LANG=$LANG
       fi
   
       # remove pointless services in a container
       chroot $rootfs /usr/sbin/update-rc.d -f umountfs remove
       chroot $rootfs /usr/sbin/update-rc.d -f hwclock.sh remove
       chroot $rootfs /usr/sbin/update-rc.d -f hwclockfirst.sh remove
   
       echo "root:root" | chroot $rootfs chpasswd
       echo "Root password is 'root', please change !"
   
       return 0
   }
   
   download_debian()
   {
       packages=\
   ifupdown,\
   locales,\
   libui-dialog-perl,\
   dialog,\
   isc-dhcp-client,\
   netbase,\
   net-tools,\
   iproute,\
   vim,\
   openssh-server
   
       cache=$1
       arch=$2
   
       # check the mini debian was not already downloaded
       mkdir -p "$cache/partial-$arch"
       if [ $? -ne 0 ]; then
           echo "Failed to create '$cache/partial-$arch' directory"
        return 1
       fi
   
       # download a mini debian into a cache
       echo "Downloading debian minimal ..."
       debootstrap --verbose --variant=minbase --arch=$arch \
       --include $packages \
       testing $cache/partial-$arch http://ftp.us.debian.org/debian
       if [ $? -ne 0 ]; then
       echo "Failed to download the rootfs, aborting."
       return 1
       fi
   
       mv "$1/partial-$arch" "$1/rootfs-$arch"
       echo "Download complete."
   
       return 0
   }
   
   copy_debian()
   {
       cache=$1
       arch=$2
       rootfs=$3
   
       # make a local copy of the minidebian
       echo -n "Copying rootfs to $rootfs..."
       cp -a $cache/rootfs-$arch $rootfs || return 1
       return 0
   }
   
   install_debian()
   {
       cache="/var/cache/lxc/debian-testing"
       rootfs=$1
       mkdir -p /var/lock/subsys/
       (
           flock -n -x 200
           if [ $? -ne 0 ]; then
               echo "Cache repository is busy."
               return 1
           fi
   
           arch=$(arch)
           if [ "$arch" == "x86_64" ]; then
               arch=amd64
           fi
   
           if [ "$arch" == "i686" ]; then
               arch=i386
           fi
   
           echo "Checking cache download in $cache/rootfs-$arch ... "
           if [ ! -e "$cache/rootfs-$arch" ]; then
               download_debian $cache $arch
               if [ $? -ne 0 ]; then
                   echo "Failed to download 'debian base'"
                   return 1
               fi
           fi
   
           copy_debian $cache $arch $rootfs
           if [ $? -ne 0 ]; then
               echo "Failed to copy rootfs"
               return 1
           fi
   
           return 0
   
       ) 200>/var/lock/subsys/lxc
   
       return $?
   }
   
   copy_configuration()
   {
       path=$1
       rootfs=$2
       name=$3
   
       cat <<EOF >> $path/config
   lxc.tty = 4
   lxc.pts = 1024
   lxc.rootfs = $rootfs
   lxc.cgroup.devices.deny = a
   # /dev/null and zero
   lxc.cgroup.devices.allow = c 1:3 rwm
   lxc.cgroup.devices.allow = c 1:5 rwm
   # consoles
   lxc.cgroup.devices.allow = c 5:1 rwm
   lxc.cgroup.devices.allow = c 5:0 rwm
   lxc.cgroup.devices.allow = c 4:0 rwm
   lxc.cgroup.devices.allow = c 4:1 rwm
   # /dev/{,u}random
   lxc.cgroup.devices.allow = c 1:9 rwm
   lxc.cgroup.devices.allow = c 1:8 rwm
   lxc.cgroup.devices.allow = c 136:* rwm
   lxc.cgroup.devices.allow = c 5:2 rwm
   # rtc
   lxc.cgroup.devices.allow = c 254:0 rwm
   
   # mounts point
   lxc.mount.entry=proc $rootfs/proc proc nodev,noexec,nosuid 0 0
   lxc.mount.entry=devpts $rootfs/dev/pts devpts defaults 0 0
   lxc.mount.entry=sysfs $rootfs/sys sysfs defaults  0 0
   
   lxc.utsname = $name
   lxc.network.type = veth
   lxc.network.flags = up
   lxc.network.link = br0
   # It is fine to be commented out
   #lxc.network.ipv4 = 192.168.10.21/24
   # Change this
   # lxc.network.hwaddr = 00:11:22:33:44:00
   EOF
   
       if [ $? -ne 0 ]; then
           echo "Failed to add configuration"
           return 1
       fi
   
       return 0
   }
   
   clean()
   {
       cache="/var/cache/lxc/debian-testing"
   
       if [ ! -e $cache ]; then
           exit 0
       fi
   
       # lock, so we won't purge while someone is creating a repository
       (
           flock -n -x 200
           if [ $? != 0 ]; then
               echo "Cache repository is busy."
               exit 1
           fi
   
           echo -n "Purging the download cache..."
           rm --preserve-root --one-file-system -rf $cache && echo "Done." || exit 1
           exit 0
   
       ) 200>/var/lock/subsys/lxc
   }
   
   usage()
   {
       cat <<EOF
   $1 -h|--help -p|--path=<path> --clean
   EOF
       return 0
   }
   
   options=$(getopt -o hp:n:c -l help,path:,name:,clean -- "$@")
   if [ $? -ne 0 ]; then
       usage $(basename $0)
       exit 1
   fi
   eval set -- "$options"
   
   while true
   do
       case "$1" in
           -h|--help)      usage $0 && exit 0;;
           -p|--path)      path=$2; shift 2;;
           -n|--name)      name=$2; shift 2;;
           -c|--clean)     clean=$2; shift 2;;
           --)             shift 1; break ;;
           *)              break ;;
       esac
   done
   
   if [ ! -z "$clean" -a -z "$path" ]; then
       clean || exit 1
       exit 0
   fi
   
   type debootstrap
   if [ $? -ne 0 ]; then
       echo "'debootstrap' command is missing"
       exit 1
   fi
   
   if [ -z "$path" ]; then
       echo "'path' parameter is required"
       exit 1
   fi
   
   if [ "$(id -u)" != "0" ]; then
       echo "This script should be run as 'root'"
       exit 1
   fi
   
   rootfs=$path/rootfs
   
   install_debian $rootfs
   if [ $? -ne 0 ]; then
       echo "failed to install debian"
       exit 1
   fi
   
   configure_debian $rootfs $name
   if [ $? -ne 0 ]; then
       echo "failed to configure debian for a container"
       exit 1
   fi
   
   copy_configuration $path $rootfs $name
   if [ $? -ne 0 ]; then
       echo "failed write configuration file"
       exit 1
   fi
   
   if [ ! -z $clean ]; then
       clean || exit 1
       exit 0
   fi
   

2. Make the file executable:

   chmod +x lxc-debian-testing
   

Create LXC Linux Container

We are going create a linux container based on debian testing.

1. Let give the machine name vm0.

   lxc1:~# mkdir -p /var/lib/lxc/vm0
   lxc1:~# ./lxc-debian-testing -p /var/lib/lxc/vm0 -n vm0
   debootstrap is /usr/sbin/debootstrap
   Checking cache download in /var/cache/lxc/debian-testing/rootfs-i386 ... 
   Downloading debian minimal ...
   ...
   Download complete.
   Copying rootfs to /var/lib/lxc/vm0/rootfs...Generating locales (this might take a while)...
     en_US.UTF-8... done
   Generation complete.
   ...
   Root password is 'root', please change !
   

2. Set network adapter mac address (must be unique):

   lxc1:~# cd /var/lib/lxc/vm0
   lxc1:/var/lib/lxc/vm0# echo "lxc.network.hwaddr = 00:AF:22:33:44:00" >> config
   

3. Make some clean up and backup:

   
   lxc1:/var/lib/lxc/vm0# chroot rootfs/
   root@lxc1:/# apt-get update && apt-get -y upgrade && apt-get clean && apt-get autoclean
   ...
   lxc1:/# exit
   lxc1:/var/lib/lxc/vm0# du -hs rootfs
   235M vm0
   lxc1:/var/lib/lxc/vm0# tar czf ../vm0.tgz config rootfs/
   lxc1:/var/lib/lxc/vm0# cd .. && ls -lh | grep tgz
   -rw-r--r-- 1 root root  80M vm0.tgz