Elastic Docker Swarm

Often, the Docker daemon is started with too low a limit for lockable memory. That's the limit you are seeing in your logs:

Increase RLIMIT_MEMLOCK, soft limit: 65536, hard limit: 65536
The containers inherit this limit, which then becomes a problem for Elasticsearch when it tries lock more memory than allowed.

If you look at your Docker daemon's limits, you will probably see this:

# grep locked /proc/$(ps --no-headers -o pid -C dockerd | tr -d ' ')/limits
Max locked memory         65536                65536                bytes
When we would much prefer to see:

# grep locked /proc/$(ps --no-headers -o pid -C dockerd | tr -d ' ')/limits
Max locked memory         unlimited            unlimited            bytes
It depends on your system how to go about changing the limit, but on my fairly standard Ubuntu system I was able to do this:

echo -e "[Service]\nLimitMEMLOCK=infinity" | SYSTEMD_EDITOR=tee systemctl edit docker.service
systemctl daemon-reload
systemctl restart docker

https://github.com/elastic/elasticsearch-docker/issues/152#issuecomment-372903395