[quote="DavidTurner, post:2, topic:156059, full:true"]
This looks like a connectivity problem outside of Elasticsearch. When you try using `telnet` from the affected node to the master, are you sure you're using the same address and port as Elasticsearch is using Is there anything unusual about your network? Can you make sure you're using IP addresses rather than hostnames everywhere to rule out a DNS issue?

I used the ip/port found in the log with telnet, so it's the same. I already use IP addresses everywhere, no DNS.
The only "unusual" thing I do is that the nodes are inside Docker, but I do the netstat/telnet inside the containers.