Fix disk migration when datastore_cluster_id changes

[pascal-hofmann]

Description

When changing the datastore_cluster_id of a vsphere_virtual_machine the disks are not migrated to datastores of the new datastore cluster because no storage migration is triggered. This PR fixes this.

Acceptance tests

• Have you added an acceptance test for the functionality being added?

  No. There used to be acceptance tests for this functionality that have been disabled with Modify acceptance tests for simple test environment #1090 and removed with Linter fixes #1416.

Release Note

resource/virtual_machine: Fix migration of all disks and configuration files when the datastore_cluster_id is changed on the resource. GH-1546

References

Closes #1454

• This fixes the issue described in my comment on Updating the datastore_id on the r/virtual_machine does not apply to disk sub-resources #1268 (comment), which is different from Updating the datastore_id on the r/virtual_machine does not apply to disk sub-resources #1268 itself.
• I think storage migration broke due to HasChange returns false for SetNewComputed attributes terraform-plugin-sdk#165

[appilon]

@tenthirtyam Can this be manualy reproduced and verified to be fixed?

[tenthirtyam]

@appilon, yes! I can test this with some NFS-backed datastore clusters to confirm and will report back the results.

Stay tuned!

[tenthirtyam]

Status: Currently running some change of datastore_cluster_id tests based on the change and some regression testing on datastore_id to ensure no implications.

[tenthirtyam]

I've reviewed this change in my testbed under vSphere v7.0.3c with two NFS-backed datastore clusters.

I can confirm that it resolves the linked issue.

• ✅ When changing datastore_cluster_id at the top-most level of a vsphere_virtual_machine resource, all disks are relocated to the updated datastore_cluster_id.
• ✅ No regression impact to changing to datastore_id at the top-most level of a vsphere_virtual_machine resource or at the disk level.

Notes:

• 🧹 While changes to datastore_cluster_id at the top-most will move all disks, for datastore_id it will only move the VM configuration (e.g. .vmx) files. This is not a regression, but it is the current behavior. It is overcome by adding datastore_id to each disk.
• 🛠️ Changes between datastore_cluster_id to datastore_id (and visa-versa) will not move the resource's disks between the two. While this is not a regression and is the current behavior, it is not ideal.

[tenthirtyam]

See #1546 (comment).

[github-actions]

This functionality has been released in v2.1.0 of the Terraform Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

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[github-actions]

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