From the output of kubectl describe pods (or kubectl get pod), we can see that the IP address of the Pod named elasticsearch-699c7dd54f-n5tmq is listed as 172.17.0.5. Since our machine is the node that this Pod runs on, we can access the Pod using this private IP address.
The Elasticsearch API should be listening to port 9200. Therefore, if we make a GET request to http://172.17.0.5:9200/, we should expect Elasticsearch to reply with a JSON object:
$ curl http://172.17.0.5:9200/ { "name" : "CKaMZGV", "cluster_name" : "docker-cluster", "cluster_uuid" : "dCAcFnvOQFuU8pTgw4utwQ", "version" : { "number" : "6.3.2", "lucene_version" : "7.3.1" ... }, "tagline" : "You Know, for Search" }
We can do the same for Pods elasticsearch-699c7dd54f-pft9k and elasticsearch-699c7dd54f-pm2wz, which have the IPs 172.17.0.4 and 172.17.0.6, respectively:
$ kubectl get pods -l app=elasticsearch -o=custom-columns=NAME:.metadata.name,IP:.status.podIP NAME IP...