OSDOCS-15215#Volume populators TP > GA

[lpettyjo]

Version(s): 4.20+

Issue: https://issues.redhat.com/browse/OSDOCS-15215

Link to docs preview: https://96030--ocpdocs-pr.netlify.app/openshift-enterprise/latest/storage/container_storage_interface/persistent-storage-csi-vol-populators.html

QE review:

• QE has approved this change.

Additional information:

PTAL: @gcharot @RomanBednar @radeore

[ocpdocs-previewbot]

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[RomanBednar]

@lpettyjo This doc describes how to configure CR and CRD which is required for working with populators in k8s/OpenShift, however that's just a fraction of the hole feature and we're missing some crucial parts:

1. Populator authors have to write the code to populate the volumes and deploy it. In other words, if we create just Hello CR and CRD - nothing will happen without the populator being deployed. Unfortunately, we don't have much from upstream apart from code examples: https://github.com/kubernetes-csi/lib-volume-populator/blob/master/example/hello-populator/main.go

2. Populator authors have to create VolumePopulator CR to register their populator CR (e.g. Hello ) otherwise the validator would emit events with errors, this is quite well described in upstream enhancement: https://github.com/kubernetes/enhancements/blob/63d4f6f2aa0e2eb0b83067b067c4949643b1b24c/keps/sig-storage/1495-volume-populators/README.md?plain=1#L160-L202

Actually, you could follow most of the upstream docs since the only difference in OpenShift is that we install the validator and VolumePopulator CRD, while in k8s users have to do that themselves. However we should not reference upstream resources directly (like code examples, or deployments using upstream images), so I'm not sure how to document populator development process nicely...