I've been trying to get Elasticsearch running on K8s using the [newly-promoted-to-stable helm chart](https://github.com/helm/charts/tree/master/stable/elasticsearch), which works fine, BTW, for elasticsearch v 6.4.2. However, we're tied to a grails app that requires elasticsearch v 5.5.3, for which we don't have the ability to upgrade. I've downgraded the elasticsearch image version in the chart to 5.5.3 (and also tried v 5.6.12) but it fails to start.

I looked into the [elasticsearch operator](https://github.com/upmc-enterprises/elasticsearch-operator), but it's currently set up to work with AWS S3 storage types, out of the box, and GCP with a little work (although no snapshot ability). Before I dive into this, I'd like to know if it will work with 5.5.3, to begin with.

Does anyone know if I can get elasticsearch v 5.5.3 running in a k8s cluster? I would say using a k8s StatefulSet at a minimum.

Thanks!

**Update**

I suppose I should have given the errors that the existing helm chart is having when downgrading elasticsearch image to 5.5.3.

master-0 pod fails to start with:

`Error injecting constructor, ElasticsearchException[java.io.IOException: failed to read [id:15, legacy:false, file:/usr/share/elasticsearch/data/nodes/0/_state/global-15.st]]; nested: IOException[failed to read [id:15, legacy:false, file:/usr/share/elasticsearch/data/nodes/0/_state/global-15.st]]; nested: ElasticsearchException[Unknown license version found, please upgrade all nodes to the latest elasticsearch-license plugin];
 at org.elasticsearch.gateway.GatewayMetaState.<init>(Unknown Source)
 while locating org.elasticsearch.gateway.GatewayMetaState
 for parameter 4 at org.elasticsearch.gateway.GatewayService.<init>(Unknown Source)
 while locating org.elasticsearch.gateway.GatewayService
Caused by: ElasticsearchException[java.io.IOException: failed to read [id:15, legacy:false, file:/usr/share/elasticsearch/data/nodes/0/_state/global-15.st]]; nested: IOException[failed to read [id:15, legacy:false, file:/usr/share/elasticsearch/data/nodes/0/_state/global-15.st]]; nested: ElasticsearchException[Unknown license version found, please upgrade all nodes to the latest elasticsearch-license plugin];`

The client pods fail with:

`[2018-10-22T17:52:51,835][WARN ][o.e.d.z.UnicastZenPing ] [elasticsearch-client-6bf954c595-7zlpc] failed to resolve host [elasticsearch-discovery]
java.net.UnknownHostException: elasticsearch-discovery`

Clearly, it's expecting a later elasticsearch version.