Fixing error "Unable to lock JVM memory (ENOMEM)" in docker containers

fix ENOMEM in docker container

Taken from https://www.youtube.com/watch?v=jgFzhhc7-e8

TLDR; set `LimitMEMLOCK=infinity` for the docker deamon to trickle down to the containers.

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What's the PID of your Docker daemon?
> sudo service docker status | grep -P -o 'dockerd\[[0-9]+\]' | head -1 | grep -P -o [0-9]+  

Check the limits for that process
> cat /proc/`service docker status | grep -P -o 'dockerd\[[0-9]+\]' | head -1 | grep -P -o [0-9]+`/limits
The limit `Max locked memory` needs to be set to `UNLIMITED`.

Check which config file to change
> FILE=`sudo service docker status | grep 'Loaded: loaded (' | sed 's|[ ]*Loaded: loaded (||' | sed 's|;.*||'`
> vim $FILE

**Make sure you have a line with `LimitMEMLOCK=infinity` under the `[Service]` section.**

Restart the docker daemon
> sudo systemctl daemon-reload
> sudo service docker restart

Check the Memlock limit again. It should now be set to "infinity":
> cat /proc/`service docker status | grep -P -o 'dockerd\[[0-9]+\]' | head -1 | grep -P -o [0-9]+`/limits

You can also start your docker container, exec in to a shell and check the limit on a process there
> start docker container; exec to shell; cat /proc/1/limits