Assign way more replicas than you have of memory on all nodes and watch the Swarm crash which can easily reproduce in a small VMfor testing.
root@Deb11Docker01:~# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAM........
Apr 17 11:55:47 Cluster01 heartbeat: [1426]: WARN: ha_msg_add_nv_depth: line doesn't contain '='
Apr 17 11:55:47 Cluster01 heartbeat: [1426]: info: >>>
Apr 17 11:55:47 Cluster01 heartbeat: [1426]: ERROR: NV failure (msgfromsteam): [>>>
]
I have never been able to reproduce the above but it happened on heartbeat-3.04-2 when Itook a node down for testing.
One thing Ibelieve caused it was by configuring ha.cf........