A small gnatsd image based apcera/gnatsd. This image only contains the gnatsd executable, and is configured to pass the command to be run as the arguments to it.
You can run it in the simplest sense with
docker run smarthall/gnatsd
As usual you can add
-P to expose the port to your machine instead of just linked containers.
You can also supply a config file by mounting it and passing the
docker run -v /path/to/gnatsd.conf:/gnatsd.conf:ro smarthall/gnatsd -c /gnatsd.conf