A shell script to quickly clone an existing LXC Container (e.g. a plain CentOS6 installation) and to update the local DNS to make it accessible.

create-container.sh

#!/bin/bash

HOSTSFILE="/etc/hosts"

if test -z "$1"
then
  echo "Please provide a container/host name."
  exit 1
else
  NAME="$1"
fi

if [ $(whoami) != "root" ]
then
  echo "Root privileges required to run this script!"
  exit 1
fi

if test -n "$(lxc-ls -1 | grep $NAME)"
then
  read -n 1 -p "$NAME exists. OK to destroy (y/n)? " answer
  case ${answer:0:1} in
    y|Y )
      echo
      lxc-destroy -f -n $NAME
    ;;
    * )
      echo
      echo "OK, exiting."
      exit 0
    ;;
  esac
fi

lxc-clone -s -o centos6base -n $NAME
echo "Starting $NAME."
lxc-start -d -n $NAME

echo -n "Determining IP address."
while test -z "$HOSTIP"
do
  echo -n "."
  HOSTIP=$(lxc-info -H -i -n $NAME)
  sleep 1
done

echo
echo "$NAME has IP $HOSTIP - updating $HOSTSFILE"
if test -n "$(grep $NAME $HOSTSFILE)"
then
  sed -e "s/^\(.*\) $NAME $NAME\.local/$HOSTIP $NAME $NAME\.local/" -i $HOSTSFILE
else
  echo "$HOSTIP $NAME $NAME.local" >> $HOSTSFILE
fi

echo "Restarting dnsmasq..."
pkill -HUP dnsmasq