# import the new version of the image we want to run
imgadm import analogic/poste.io
# make note of the image uuid imported and set NEW_IMAGE to this value
UUID=91854c5c-a285-6522-9da8-e38a04116fd6
NEW_IMAGE=some_uuid
BACKUP_LOCATION=/zones/images/smtp-data.zfs
SNAPSHOT_NAME=begin

# stop the zone and make a copy of the zfs delegated setup script  
vmadm stop ${UUID}
cp /zones/${UUID}/root/etc/cont-init.d/01-init-zfs.sh /tmp

# this is not strictly necessary, but sometimes it's nice to have a backup.
echo "Backing up to $BACKUP_LOCATION..."
zfs snap zones/${UUID}/data@${SNAPSHOT_NAME}
zfs send -Recv zones/${UUID}/data@begin > $BACKUP_LOCATION

echo "Reprovisioning..."
echo '{"image_uuid": "${NEW_IMAGE}"}' | vmadm reprovision ${UUID}

# restore the zfs delegated dataset bootstrap and truncated directory setup 
# scripts back into place. this is because they have to run the first time, every 
# time and thus can't be installed from /data/_override (which is a feature that
# poste.io provides for making customizations to their image, and which is not
# a standard feature across docker images).
#
# alternatively, we could override the docker:cmd field and do something there
# or build a custom docker image.
vmadm stop ${UUID}
cp /tmp/0*.sh /zones/${UUID}/root/etc/cont-init.d/

#If, for some reason the container starts up immediately after provision, the zfs init script won't work as 
#the /data directory will be present and non-empty. If this happens, move it out of the way and restart.
# then, zlogin and verify that the /data directory has the delegated dataset (with the local and _override directories)

vmadm start ${UUID} 
# to restart with ipf running we have to reboot.
vmadm reboot ${UUID}

# restoring the delegated dataset is not necessary when we use reprovision, but is 
# kept as an example of how to do it.
zfs recv -F zones/${UUID}/data < ${BACKUP_LOCATION}
zfs rollback zones/${UUID}/data@${SNAPSHOT_NAME}
zfs destroy zones/${UUID}/data@${SNAPSHOT_NAME}

rm ${BACKUP_LOCATION}