Gotcha!

So, i was navigating through the docker container and found the container name in this file path -> /var/lib/gridstore/conf/gs_cluster.json and the clustername written in json like this

{
  "clusterName":"dockerGridDB",
  ...
}

• Additionally you can execute this commands to get the cluster name

docker exec -it griddb-server bash
cat /var/lib/gridstore/conf/gs_cluster.json