lxc-ceph.sh

#! /bin/bash

# A Pacemaker resource agent that runs LXC containers using Ceph as a storage
# backend.
# Place in /usr/lib/ocf/resource.d/custom to use with your Pacemaker
# installation

LXC="/var/lib/lxc"

# Init OCF

: ${OCF_FUNCTIONS=${OCF_ROOT}/resource.d/heartbeat/.ocf-shellfuncs}
. ${OCF_FUNCTIONS}

USAGE="Usage: $0 {start|stop|monitor|meta-data}"
CONTAINER=$OCF_RESKEY_container
POOL=$OCF_RESKEY_pool

function usage() {
	echo $USAGE >&2
}

function metadata() {
	cat <<END
<?xml version="1.0"?>
<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
<resource-agent name="LXC_Ceph" version="1.0">
<version>1.0</version>

	<longdesc lang="en">
		This will start/stop LXC containers using Ceph as a distributed storage system
	</longdesc>

	<shortdesc lang="en">
		This will start/stop LXC containers using Ceph as a distributed storage system
	</shortdesc>

	<parameters>
		<parameter name="container" unique="1" required="1">

			<longdesc lang="en">
				Name of the container
			</longdesc>

			<shortdesc lang="en">Container name</shortdesc>

			<content type="string" />
		</parameter>

		<parameter name="pool" unique="0" required="1">

			<longdesc lang="en">
				Name of the Ceph storage pool
			</longdesc>

			<shortdesc lang="en">Ceph storage pool</shortdesc>

			<content type="string" />
		</parameter>
	</parameters>

	<actions>
		<action name="start" timeout="60" />
		<action name="stop" timeout="60" />
		<action name="monitor" timeout="120" interval="10" />
		<action name="meta-data" timeout="5" />
	</actions>

</resource-agent>
END
}

# checks if the container is running using lxc-ls
function is_running() {
	if [[ -n $(lxc-ls --running --filter=$CONTAINER) ]]; then
		return 0
	else
		return 1
	fi
}

# checks if a container's image is mounted
function is_mounted() {
	if mount | grep -q "$LXC/$CONTAINER"; then
		return 0
	else
		return 1
	fi
}

# checks if a container's RBD image is mapped
function is_mapped() {
	if [[ -b /dev/rbd/$POOL/$CONTAINER ]]; then
		return 0
	else
		return 1
	fi
}

# maps a container's image to this node
function map() {
	rbd map "$POOL/$CONTAINER"
}

# unmaps a container's image
function unmap() {
	rbd unmap "$POOL/$CONTAINER"
}

# mounts the container's image in the LXC containers directory
function fmount() {
	mkdir -p "$LXC/$CONTAINER"
	mount /dev/rbd/$POOL/$CONTAINER "$LXC/$CONTAINER"
}

# unmount the container's image
function unmount() {
	umount "$LXC/$CONTAINER" && rmdir "$LXC/$CONTAINER"
}

# starts the container (needs to mapped + mounted first)
function start_container() {
	lxc-start $CONTAINER
}

# stops the container (do this before unmounting + unmapping)
function stop_container() {
	lxc-stop $CONTAINER
}

# main start function
function start() {
	is_mapped || map
	is_mapped || return $OCF_ERR_GENERIC

	fmount
	is_mounted || return $OCF_ERR_GENERIC

	start_container
	is_running || return $OCF_ERR_GENERIC
}

# main stopping function
function stop() {
	is_running && stop_container
	is_running && return $OCF_ERR_GENERIC

	# try for 10 seconds long to unmount the container's image (sometimes it
	# complains that the mountpoint is still in use)
	counter=0
	while is_mounted && [[ $counter -lt 10 ]]; do
		unmount && continue
		sleep 1s
		((counter++))
	done
	is_mounted && return $OCF_ERR_GENERIC

	unmap
	is_mapped && return $OCF_ERR_GENERIC
	return 0
}

# checks that everything is still up and running
function monitor {
	is_running && return $OCF_SUCCESS
	is_mounted && return $OCF_ERR_GENERIC
	is_mapped && return $OCF_ERR_GENERIC
	return $OCF_NOT_RUNNING
}

case $1 in
	usage) usage;;
	start) start;;
	stop) stop;;
	monitor) monitor;;
	meta-data) metadata;;
	*) usage;;
esac

exit $?