Swarm node Status down, but node should be Ready

Question

I am trying to run a service on a swarm composed of three Raspberry PIs.
I have one manager and two worker nodes.

The problem is that sometimes the status of the worker nodes is "Down" even if the nodes are correctly switched on and connected to the network.

I just started using Docker so I might be doing something wrong, but everything seems to be correctly set.
How would you avoid that "Down" status?

Answer 1

It can depend on your exact version of docker, but your issue was seen in this thread

A possible workaround was to do a docker ps, which seems to helped nodes to join the swarm.