mirror_lxc/scripts/lxc-debian.in

#!/bin/bash
# set -ex

NAME="debian"
CONFFILE="lxc.conf"
MNTFILE="mount.conf"
UTSNAME=
IPV4="172.20.0.21"
GATEWAY="172.20.0.1"
INTERFACES="/etc/network/interfaces"
INITTAB="/etc/inittab"
HOSTNAME="/etc/hostname"
FSTAB="/etc/fstab"
CACHE="/var/cache/lxc/debian"

create() {

    # choose a container name, default is 'debian'
    echo -n "What is the name for the container ? [$NAME] "
    read _NAME_

    if [ ! -z "$_NAME_" ]; then
	NAME=$_NAME_
    fi

    # choose a hostname, default is the container name
    echo -n "What hostname do you wish for this container ? [$NAME] "
    read _UTSNAME_

    if [ ! -z "$_UTSNAME_" ]; then
	UTSNAME=$_UTSNAME_
    else
	UTSNAME=$NAME
    fi

    # choose an ipv4 address, better to choose the same network than
    # your host
    echo -n "What IP address do you wish for this container ? [$IPV4] "
    read _IPV4_

    if [ ! -z "$_IPV4_" ]; then
	IPV4=$_IPV4_
    fi

    # choose the gateway ip address
    echo -n "What is the gateway IP address ? [$GATEWAY] "
    read _GATEWAY_

    if [ ! -z "$_GATEWAY_" ]; then
	GATEWAY=$_GATEWAY_
    fi

    # the rootfs name will be build with the container name
    ROOTFS="./rootfs.$NAME"

    # check if the rootfs does already exist
    if [ ! -e "$ROOTFS" ]; then
	(
	    flock -n -x 200 

	    RES=$?
	    if [ "$RES" != "0" ]; then
		echo "Cache repository is busy."
		break
	    fi

	    echo "Choose your architecture"
	    select ARCH in amd64 i386; do
		echo "Architecture $ARCH selected"
		break;
	    done

	    # check the mini debian was not already downloaded
	    echo -n "Checking cache download ..."
	    if [ ! -e "$CACHE/rootfs-$ARCH" ]; then
		
		echo "not cached"
		
		mkdir -p "$CACHE/rootfs-$ARCH"
		
	        # download a mini debian into a cache
		echo "Downloading debian minimal ..."
		debootstrap --verbose --variant=minbase --arch=$ARCH \
		    --include apache,netbase,net-tools,iproute,openssh-server \
		    etch $CACHE/rootfs-$ARCH http://ftp.debian.org/debian
		
		RESULT=$?
		if [ "$RESULT" != "0" ]; then
		    echo "Failed to download the rootfs, aborting."
		    exit 1
		fi
		echo "Download complete."
	    else
		echo "Found."
	    fi
	    
            # make a local copy of the minidebian
	    echo -n "Copying rootfs ..."
	    cp -a $CACHE/rootfs-$ARCH $ROOTFS && echo "Done." || exit
	) 200>/var/lock/subsys/lxc
    fi


########################################
# lxc configuration files
########################################

# lxc mount point

cat <<EOF > $MNTFILE
/dev	$(pwd)/$ROOTFS/dev none bind 0 0
/dev/pts $(pwd)/$ROOTFS/dev/pts none bind 0 0
/etc/resolv.conf $(pwd)/$ROOTFS/etc/resolv.conf none ro,bind 0 0
EOF

# lxc configuration

cat <<EOF > $CONFFILE
lxc.utsname = $UTSNAME
lxc.network.type = veth
lxc.network.flags = up
lxc.network.link = br0
lxc.network.name = eth0
lxc.mount = $MNTFILE
lxc.rootfs = $ROOTFS
EOF


########################################
# rootfs configuration files tweak
########################################

# inittab

cat <<EOF > $ROOTFS/$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
EOF

# hostname
cat <<EOF > $ROOTFS/$HOSTNAME
$UTSNAME
EOF

# fstab

cat <<EOF > $ROOTFS/$FSTAB
tmpfs                   /dev/shm                tmpfs   defaults        0 0
EOF

# network

cat <<EOF > $ROOTFS/$INTERFACES
auto eth0 lo
iface eth0 inet static
address $IPV4
netmask 255.255.255.0
broadcast 0.0.0.0
up route add default gw $GATEWAY
iface lo inet loopback
EOF

# create the container object

lxc-create -n $NAME -f $CONFFILE

# remove the configuration files

rm -f $CONFFILE
rm -f $MNTFILE

echo "Done."
echo -e "\nYou can run your container with the 'lxc-start -n $NAME'\n"
}

destroy() {

    echo -n "What is the name for the container ? [$NAME] "
    read _NAME_

    if [ ! -z "$_NAME_" ]; then
	NAME=$_NAME_
    fi

    lxc-destroy -n $NAME
    RETVAL=$?
    if [ ! $RETVAL -eq 0 ]; then
	echo "Failed to destroyed '$NAME'"
	return $RETVAL;
    fi

    ROOTFS="./rootfs.$NAME"

    echo -n "Shall I remove the rootfs [y/n] ? "
    read
    if [ "$REPLY" = "y" ]; then
	rm -rf $ROOTFS
    fi

    return 0
}

help() {
    cat <<EOF

This script is a helper to create debian system containers.

The script will create the container configuration file following
the informations submitted interactively with 'lxc-debian create'

The first creation will download, with debootstrap, a debian
minimal and store it into a cache.

The script will copy from the cache the root filesystem to the
current directory.

If there is a problem with the container, (bad configuration for 
example), you can destroy the container with 'lxc-debian destroy'
but without removing the rootfs and recreate it again with
'lxc-debian create'.

If you want to create another debian container, call the 'lxc-debian
 create' again, specifying another name and new parameters.

At any time you can purge the debian cache download by calling 
'lxc-debian purge'

Have fun :)

EOF
}

purge() {

    if [ ! -e $CACHE ]; then
	exit 0
    fi

    # lock, so we won't purge while someone is creating a repository
    (
	flock -n -x 200 

	RES=$?
	if [ "$RES" != "0" ]; then
	    echo "Cache repository is busy."
	    exit 1
	fi

	echo -n "Purging the download cache..."
	# I don't use here the variable, just to be sure
	# nobody touching the CACHE variable will lead to
	# remove the real rootfs '/'.
	rm -rf /var/cache/lxc/debian/* && echo "Done." || exit 1
	exit 0

    ) 200>/var/lock/subsys/lxc
}

if [ "$(id -u)" != "0" ]; then
	echo "This script should be run as 'root'"
	exit 1
fi 

case "$1" in
    create)
	create;;
    destroy)
	destroy;;
    help)
	help;;
    purge)
	purge;;
    *)
	echo "Usage: $0 {create|destroy|purge|help}"
	exit 1;;
esac