vmsnap-rollback.scenario

# This file can be used directly by 'phd', see 'build-all.sh' in this
# directory for how it can be invoked.  The only requirement is a list
# of nodes you'd like it to modify.
#
# The scope of each command-block is controlled by the preceeding
# 'target' line. 
#
# - target=all
#   The commands are executed on evey node provided
#
# - target=local
#   The commands are executed from the node hosting phd. When not
#   using phd, they should be run from some other independant host
#   (such as the puppet master)
#
# - target=$PHD_ENV_nodes{N}
#   The commands are executed on the Nth node provided.
#   For example, to run on only the first node would be target=$PHD_ENV_nodes1
#
# We start with 3 (or more, up to 16) nodes running a minimal CentOS 6
#
# Tasks to be performed include:
# - setting up the required repositories from which to download Openstack and the HA-Addon
# - disabling firewalls and SElinux. This is a necessary evil until the proper policies can be written.
# - creating network bridges for use by VMs hosting OpenStack services
# - normalizing network interface names
# - fixing multicast
# - removing /home and making the root partition as large as possible to maximumize the amount of space available to openstack

#################################
# Scenario Requirements Section #
#################################
= VARIABLES =
PHD_ENV_snapshot_name
PHD_VAR_osp_configdir

#################################
# Scenario Requirements Section #
#################################
= REQUIREMENTS =
nodes: 3

######################
# Deployment Scripts #
######################
= SCRIPTS =

target=all
....
# get list of all VMs configured on a given host
vmlist=$(virsh list --all --name)

for vm in $vmlist; do
	# if the requested snapshot doesn't exist, don't continue with
	# disruptive actions
	if [ ! -f /localvms/${vm}-${PHD_ENV_snapshot_name}.cow ]; then
		echo "ERROR: Snapshot ${PHD_ENV_snapshot_name} does not exists"
		exit 1
	fi

	current=$(virsh snapshot-current --name $vm)
	if [ "$current" = ${PHD_ENV_snapshot_name} ]; then
		echo "ERROR: We are already at snapshot: ${PHD_ENV_snapshot_name}"
		exit 1
	fi

	# make sure that the we are rolling back to a snap
	# that is parent of the current
	snaplist=$(virsh snapshot-list --tree $vm | sed -e 's#.*|.*##g' -e 's#.*+- ##g')
	for snap in $snaplist; do
		if [ "$snap" = "${PHD_ENV_snapshot_name}" ]; then
			# we found requested snap before current and we are good
			echo "found snap ${PHD_ENV_snapshot_name}"
			break;
		fi
		if [ "$snap" = "$current" ]; then
			# current is before the requested snap, error
			echo "ERROR: Requested snap ${PHD_ENV_snapshot_name} is not a parent of current $current snap"
			exit 1
		fi
	done
done

....

target=all
....
# to roll back we need to kill hard the VMs but we want to make
# sure that the other nodes won't fence before we get to
# revert properly
systemctl stop fence_virtd

vmlist=$(virsh list --all --name)
for vm in $vmlist; do
	rollback=""

	virsh destroy $vm

	snaplist=$(virsh snapshot-list --tree $vm | sed -e 's#.*|.*##g' -e 's#.*+- ##g')

	# we need to proceed from the bottom of the list
	for snap in $snaplist; do
		rollback="$snap $rollback"
	done

	# kill all disks
	for snap in $rollback; do
		if [ "$snap" = "${PHD_ENV_snapshot_name}" ]; then
			break;
		fi
		rm -f /localvms/${vm}-${snap}.cow
		# needs extra cleaning
		case $snap in
			cinder)
				rm -rf $PHD_VAR_osp_configdir/cinder
			;;
			glance)
				rm -rf $PHD_VAR_osp_configdir/glance
			;;
		esac
	done

	# drop all childs
	virsh snapshot-delete --domain $vm ${PHD_ENV_snapshot_name} --metadata --children-only

	virsh detach-disk $vm vda --config
	virsh attach-disk $vm /localvms/$vm-${PHD_ENV_snapshot_name}.cow vda \
		--sourcetype file --type disk \
		--driver qemu --subdriver qcow2 \
		--config

done

....

target=all
....

systemctl start fence_virtd
# get list of all VMs configured on a given host
vmlist=$(virsh list --all --name)

for vm in $vmlist; do
	virsh start $vm
done
....