instant lxc cluster

start-lxc-cluster.sh

#!/bin/bash

COUNT=10
BRIDGE="br1"
FORMAT="lxc%d"
PARENT=$(hostname --fqdn)
LXC_ROOT=/srv/virt/lxc
OS_ROOT=/srv/virt/lxc/base/root

for num in $(seq 1 $COUNT)
do
  name=$(printf "$FORMAT" $num)
  utsname="${name}.${PARENT}"

  top="$LXC_ROOT/$utsname"
  mkdir -p $top

  root="${top}/root"
  rootrw="${top}/rw"
  conf="${top}/lxc.conf"
  logfile="${top}/${utsname}.log"

  # configuraable
  mac=$(printf "4a:49:43:49:79:%02x" $num)
  ip="192.168.4.$(($num + 100))/24"

  mkdir -p $rootrw $root

  # update /etc/ethers for dnsmasq
  if (grep -q $mac /etc/ethers) ; then
    sed -i "s/$mac.*$/$mac $ip/" /etc/ethers
  else
    echo "$mac $ip" >> /etc/ethers
  fi
  pkill -HUP dnsmasq

  # lxc config file
  cat > $conf <<EOF
lxc.utsname = $utsname
lxc.rootfs = $root
#lxc.tty = 1
lxc.console = $logfile
lxc.cgroup.cpuset.cpus = $(cat /cgroup/cpuset.cpus)
lxc.cgroup.cpu.shares = 100

lxc.mount.entry=none proc proc nodev,noexec,nosuid 0 0
lxc.mount.entry=none dev/shm tmpfs defaults 0 0
lxc.mount.entry=none dev/pts devpts defaults 0 0

lxc.network.type = veth
lxc.network.flags = up
lxc.network.link = $BRIDGE
lxc.network.hwaddr = $mac
lxc.network.ipv4 = $ip

lxc.cgroup.devices.deny = a
lxc.cgroup.devices.allow = c 1:3 rwm # /dev/null
lxc.cgroup.devices.allow = c 1:5 rwm # /dev/zero
lxc.cgroup.devices.allow = c 5:1 rwm # /dev/console
lxc.cgroup.devices.allow = c 5:0 rwm # /dev/tty
lxc.cgroup.devices.allow = c 4:0 rwm # /dev/tty0
lxc.cgroup.devices.allow = c 1:9 rwm # /dev/random
lxc.cgroup.devices.allow = c 1:8 rwm # /dev/urandom
lxc.cgroup.devices.allow = c 136:* rwm # /dev/pts/*
lxc.cgroup.devices.allow = c 5:2 rwm   # /dev/pts/ptmx
#lxc.cgroup.devices.allow = c 254:0 rwm
lxc.cap.drop = sys_boot sys_module sys_time
EOF

  unionfs -o cow,max_files=32768 \
    -o allow_other,use_ino,suid,dev,nonempty \
    "${rootrw}=RW:${OS_ROOT}=RO" $root

  lxc-start -d -n $name -f $conf -o $logfile
done

stop-lxc-cluster.sh

#!/bin/bash

COUNT=10
FORMAT="lxc%d"
PARENT=$(hostname --fqdn)
LXC_ROOT=/srv/virt/lxc

for num in $(seq 1 $COUNT)
do
  name=$(printf "$FORMAT" $num)
  utsname="${name}.${PARENT}"
  top="$LXC_ROOT/$utsname"
  root="${top}/root"

  lxc-stop -n $name

  umount -t fuse.unionfs $root
done

I have a full debootstrapped Ubuntu Lucid in /srv/virt/lxc/base/root . I've also used this lxc conf with CentOS 5 and Funtoo in the past.