lxc-centos-swair

#!/bin/bash

echo "Creating centos-6 node..."

configure_centos()
{
    rootfs=$1
    hostname=$2

	# disable selinux in centos
    mkdir -p $rootfs/selinux
    echo 0 > $rootfs/selinux/enforce

	# add host root ssh access

	cp /usr/lib/lxc/templates/files/rc.local $rootfs/etc/rc.local

    # set the hostname
    cat <<EOF > $rootfs/etc/hostname
$hostname
EOF
    # set minimal hosts
    cat <<EOF > $rootfs/etc/hosts
127.0.0.1 localhost $hostname
EOF

    cat <<EOF > $rootfs/etc/init/console.conf
# console - mingetty
#
# This service maintains a console on tty1 from the point the system is
# started until it is shut down again.

start on stopped rc RUNLEVEL=[2345]
stop on runlevel [!2345]

respawn
exec /sbin/mingetty console
EOF

	cat <<EOF > $rootfs/etc/fstab
none /dev/pts devpts defaults 0 0
EOF

	sed -i -e 's:/sbin/start_udev:#/sbin/start_udev:' $rootfs/etc/rc.d/rc.sysinit

	sed -i -e 's:\(Defaults *requiretty\):# \1:' $rootfs/etc/sudoers

	# create necessary devices
	rm $rootfs/dev/null
	mknod -m 666 $rootfs/dev/null c 1 3
	mknod -m 666 $rootfs/dev/random c 1 8
	mknod -m 666 $rootfs/dev/urandom c 1 9
	mkdir -m 755 $rootfs/dev/pts
	mknod -m 666 $rootfs/dev/tty c 5 0
	mknod -m 666 $rootfs/dev/tty0 c 4 0
	mknod -m 666 $rootfs/dev/tty1 c 4 1
	mknod -m 666 $rootfs/dev/tty2 c 4 2
	mknod -m 666 $rootfs/dev/tty3 c 4 3
	mknod -m 666 $rootfs/dev/tty4 c 4 4
	mknod -m 600 $rootfs/dev/console c 5 1
	mknod -m 666 $rootfs/dev/full c 1 7
	mknod -m 600 $rootfs/dev/initctl p

	# change root password
    echo "Set root password to 'root'"
    echo "root:root" | chroot $rootfs chpasswd

    return 0
}

copy_centos()
{
    cache=$1
    arch=$2
    rootfs=$3

    # make a local copy of the minicentos
    echo "Extracting rootfs image to $rootfs ..."
    mkdir $rootfs
    tar zxf /home/swair.s/centos-6-$arch.tar.gz -C $rootfs || return 1
    return 0
}

install_centos()
{
    cache="/var/cache/lxc"
    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 image cache in $cache/rootfs-$arch ... "
	if [ ! -e "$cache/rootfs-$arch" ]; then
	    if [ $? -ne 0 ]; then
		echo "Failed to download 'centos base'"
		return 1
	    fi
	fi

	copy_centos $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.utsname = $name

lxc.tty = 4
lxc.pts = 1024
lxc.rootfs = $rootfs
lxc.mount  = $path/fstab

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
EOF

    cat <<EOF > $path/fstab
proc            $rootfs/proc         proc    nodev,noexec,nosuid 0 0
devpts          $rootfs/dev/pts      devpts defaults 0 0
sysfs           $rootfs/sys          sysfs defaults  0 0
EOF

    if [ $? -ne 0 ]; then
		echo "Failed to add configuration"
		return 1
    fi

    return 0
}

clean()
{
    cache="/var/cache/lxc"

    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

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_centos $rootfs
if [ $? -ne 0 ]; then
    echo "failed to install centos"
    exit 1
fi

configure_centos $rootfs $name
if [ $? -ne 0 ]; then
    echo "failed to configure centos 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