Allow CR with custom dashboard image that is different from general custom image or default image

[aarontams]

Task Allow config the OpenSearchCluster CR to use a specific image for the dashboards only

Limit Currently, the OpenSearchCluster CR only allows customize the dashboard image through the spec.general.image. But the CR value in spec.general.image will also be used by all the opensearch cluster nodes (master, ingest, and data).

Scenario Some users build the opensearch cluster (a.k.a ES cluster) and opensearch dashboard (a.k.a Kibana) separately and put the images in two different docker registry repos. They need a way to individualize both images for opensearch cluster and opensearch dashboard.

Solution To allow the CR to customize the dashboard image only without affecting other components, the simplest way is to introduce an ImageSpec struct within spec.dashboards. For example:

spec:
  dashboards:
    imagePullPolicy: Always
    image: my.io/awesomeapps/opensearch-dashboard:3.2.1-canary

Implementation With this MR, the opensearch operator will choose the dashboard image in the following order:

1. CR value inspec.dashboards.image if specified.
2. CR value in spec.general.image if specified.
3. Default hard coded docker.io/opensearchproject/opensearch-dashboards: + cr.Spec.Dashboards.Version in reconcile-helpers.go.

[aarontams]

When I did the docket-build, as expect the opensearch-operator/config/crd/bases/opensearch.opster.io_opensearchclusters.yaml file was updated.

My question is even before my PR, the updated opensearch.opster.io_opensearchclusters.yaml content is different from charts/opensearch-operator/templates/opensearchclusters.opensearch.opster.io-crd.yaml
I suspected they should be the same but theopensearchclusters.opensearch.opster.io-crd.yaml is not updated every time when the CR struct is changes.

See another PR: https://github.com/Opster/opensearch-k8s-operator/pull/175/files

I am not sure this snippet is needed for PR or not. I can remove it if it is not needed.

[swoehrl-mw]

We are currently working on automatically updating the CRD in the helm chart. But you can keep the change in.

[aarontams]

Since this code snippet is used 3 times in this go file, refactoring the code to call useCustomImage func for easy maintenance going forward.

[aarontams]

Reviewers
I am not seeing the spec.general.image (imagePullPolicy, imagePullSecrets) defined in crd.md. I am hesitate to add the new fields from this MR to spec.database. Please advise.

[swoehrl-mw]

Hi @aarontams. Thank you for your PR.
Could you please add a unittest for the new functionality (probably in opensearch-operator/pkg/reconcilers/dashboards_test.go)
and please add the new fields to the crd.md (that the fields for spec.general.image are not there is an omission, in general every field of the CRD should be documented).
Otherwise code looks good to me.

[swoehrl-mw]

We are currently working on automatically updating the CRD in the helm chart. But you can keep the change in.

[aarontams]

Could you please add a unittest for the new functionality (probably in opensearch-operator/pkg/reconcilers/dashboards_test.go)

Will do in next PR update.

and please add the new fields to the crd.md (that the fields for spec.general.image are not there is an omission, in general every field of the CRD should be documented).

I was thinking about adding the new fields to crd.md, but didn't see the ImageSpec defined in GeneralConfig.

Yes, I will add that in next PR update.

Thanks for reviewing my PR.

[aarontams]

@swoehrl-mw
Updated the PR with

• new fields in crd.md
• unittest for the new functionality

Looking forward to having you to review it again.

[swoehrl-mw]

LGTM