problem

There is a problem with the elasticsearch ready probe when running on a single replica cluster.

Warning  Unhealthy               91s (x14 over 3m42s)  kubelet          Readiness probe failed: Waiting for elasticsearch cluster to become ready (request params: "wait_for_status=green&timeout=1s" )
Cluster is not yet ready (request params: "wait_for_status=green&timeout=1s" )

Solution:

If you are running a single copy cluster, add the following helm values:

clusterHealthCheckParams: "wait_for_status=yellow&timeout=1s"

For a single replica cluster, your status will never turn green.

The following values should be valid:

replicas: 1
minimumMasterNodes: 1
clusterHealthCheckParams: 'wait_for_status=yellow&timeout=1s'