ES Statefulset empty initContainers fix

[cloudziu]

Modyfied elasticsearch statefulset template, so if none of the initContainers are declared, there will be no initContainers: directive.

• Chart version not bumped (the versions are all bumped and released at the same time)
• README.md updated with any new values or changes
• Updated template tests in ${CHART}/tests/*.py
• Updated integration tests in ${CHART}/examples/*/test/goss.yaml

Problem

Unable to patch image names/tags by using kustomize, when an empty initContainers directive is provided.
Error:
Error: containers path is not of type []interface{} but <nil>

Example with turned off all initContainers in values files.

extraInitContainers: []

sysctlInitContainer:
  enabled: false

keystore: []

Part of the statefulset

      terminationGracePeriodSeconds: 120
      volumes:
      enableServiceLinks: true
      initContainers:

      containers:
      - name: "elasticsearch"
        securityContext:
          capabilities:
            drop:
            - ALL

A fast workaround is to add a dummy initContainer.

What I've done in PR

Add an {{- if or }} statement to the initContainers: directive that will check if any of them is enabled.

Chart version

Elasticsearch chart
elastic/elasticsearch 7.9.0

Tools versions

Helm version
Client: &version.Version{SemVer:"v2.16.10", GitCommit:"bceca24a91639f045f22ab0f41e47589a932cf5e", GitTreeState:"clean"}

kubectl version
Client Version: version.Info{Major:"1", Minor:"18", GitVersion:"v1.18.0", GitCommit:"9e991415386e4cf155a24b1da15becaa390438d8", GitTreeState:"clean", BuildDate:"2020-03-25T14:58:59Z", GoVersion:"go1.13.8", Compiler:"gc", Platform:"linux/amd64"}

[elasticmachine]

Since this is a community submitted pull request, a Jenkins build has not been kicked off automatically. Can an Elastic organization member please verify the contents of this patch and then kick off a build manually?

[botelastic]

This PR has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions. To track this PR (even if closed), please open a corresponding issue if one does not already exist.

[jmlrt]

jenkins test this please

[jmlrt]

LGTM⛴