We use the following simple script/Docker container at Magnet.me to kill a machine really hard if another node becomes a master for an HA-environment.
You can use the container like this (assumed the private key is stored in /tmp/privateKey
):
docker run \
-v /tmp/privateKey:/opt/privateKey \
-e TRANSIP_USER=magnetme \
-e DOOMED_VPS=magnetme-vps69 \
magnetme/transip-stonith