I have a working kubernetes cluster with the elasticsearch up and running returning a 200. I am trying to install the HQ plugin. So i log into the node running the es-client, and attach to the docker container. When i execute the command

/ # /elasticsearch/bin/plugin  -install royrusso/elasticsearch-HQ

i am getting

Exception in thread "main" java.lang.IllegalArgumentException: Could not resolve placeholder 'DISCOVERY_SERVICE'

I am using the yaml files from here https://github.com/pires/kubernetes-elasticsearch-cluster with these modifications https://github.com/UKHomeOffice/docker-elasticsearch/blob/master/examples/kubernetes.md

Am i missing something?

Thanks in advance