Feature Overview (aka. Goal Summary)  

Allow customers to migrate CNS volumes (i.e vsphere CSI volumes) from one datastore to another.

This operator relies on a new VMware CNS API and requires 8.0.2 or 7.0 Update 3o minimum versions

https://docs.vmware.com/en/VMware-vSphere/8.0/rn/vsphere-vcenter-server-802-release-notes/index.html

In 4.17 we shipped a devpreview CLI tool (OCPSTRAT-1619) to cover existing urgent requests. This CLI tool will be removed as soon as this feature is available in OCP.

Goals (aka. expected user outcomes)

Often our customers are looking to migrate volumes between datastores because they are running out of space in current datastore or want to move to more performant datastore. Previously this was almost impossible or required modifying PV specs by hand to accomplish this. It was also very error prone.

As a first version, we developed a CLI tool that is shipped as part of the vsphere CSI operator. We keep this tooling internal for now, support can guide customers on a per request basis. This is to manage current urgent customer's requests, a CLI tool is easier and faster to develop it can also easily be used in previous OCP releases.

After multiple discussion with VMware we now have confidence that we can rely on their built-in vSphere UI tool to migrate CNS volume from one datastore to another. This includes attached and detached volumes. Vmware confirmed they have confidence in this scenario and they fully support this operation for attached volumes.

Requirements (aka. Acceptance Criteria):

SInce the feature is external to OCP, it is mostly a matter of testing it works as expected with OCP but customers will be redirected to Vmware documentation as all the steps are done through the vSphere UI.

Perform testing for attached and detached volumes + special cases such as RWX, zonal, encrypted.

Anyone reviewing this Feature needs to know which deployment configurations that the Feature will apply to (or not) once it's been completed.  Describe specific needs (or indicate N/A) for each of the following deployment scenarios. For specific configurations that are out-of-scope for a given release, ensure you provide the OCPSTRAT (for the future to be supported configuration) as well.

Use Cases (Optional):

As a admin - want to migrate all my PVs or optional PVCs belonging to certain namespace to a different datastore within cluster without potentially requiring extended downtime.

1. I want to move volumes to another datastore that has better performances
2. I want to move volumes to another datastore current the current one is getting full
3. I want to move all volumes to another datastore because the current one is being decommissioned.

Questions to Answer (Optional):

Get full support confirmation from vmware that their CNS volume migration feature 

• Can be supported for OCP - YES
• is supported with attached volumes - YES
• Should detect if a volume is not migreable - YES

Out of Scope

Limited to what VMware supports. At the moment only one volume can be migrated at a time.

Background

We had a lot of requests to migrate volumes between datastore for multiple reason. Up until now it was not natively supported by VMware. In 8.0.2 they added a CNS API and a vsphere UI feature to perform volume migration.

In 4.17 we shipped a devpreview CLI tool (OCPSTRAT-1619) to cover existing urgent requests. This CLI tool will be removed as soon as this feature is available in OCP.

This feature also includes the work needed to remove the CLI tool

Customer Considerations

Need to be explicit on requirements and limitations.

Documentation Considerations

Documented as part of the vsphere CSI OCP documentation. 

Specify min vsphere version. Document any limitation found during testing

Redirect to vmware documentation.

Announce removal of the CLI tool + update KB.

Interoperability Considerations

OCP on vSphere only