GCP - Add exception for onHostMaintenance Migrate on confidential compute n2d instances

[WTFKr0]

This PR closes #1405

Context

Provisionning Machines on GCP Provider
With confidential compute enabled
Try to set onHostMaintenance to Migrate

Current Issue

Today the webhook refused this case, as it is forbidden by default on GCP.

But an exception exists on n2d series
See this doc for information : https://cloud.google.com/confidential-computing/confidential-vm/docs/troubleshoot-live-migration

Resolution

Add an exception on the webhhook for the n2d series VM, and accept the Migrate onHostMaintenance

Environment

This issue is present on Openshift 4.16, 4.18 and 4.19 for sure

[openshift-ci]

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[openshift-ci]

Hi @WTFKr0. Thanks for your PR.

I'm waiting for a openshift member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[sunzhaohua2]

@miyadav checked with PR & confidentialCompute: Enabled for n2d

• No onHostMaintenance field works well, instance running successfully .
• With onHostMaintenance: Migrate works well , instance running successfully.

Both blocked by webhooks , without PR.

machineType: n2d-standard-4 
onHostMaintenance: Migrate 
confidentialCompute: Enabled

[bgartzi]

I'm also opening another discussion thread:

I can see in https://cloud.google.com/confidential-computing/confidential-vm/docs/troubleshoot-live-migration that live migration in AMD SEV machines is only supported with n2d machines with the AMD EPYC Milan CPU platform.

n2d machines run on EPYC Milan and EPYC Rome (deprecated according to GCP documentation). Do we need to check the CPU platform is properly set too?

We don't currently support CPU platform configuration in the GCP provider. IIUC, the closest we can get to this is by setting the Instance MinCpuPlatform field to EPYC Milan.

If we need to run this check too, we would need to add a new field in the openshift API to support it.

[bgartzi]

This condition would let SEV-SNP n2d machines to be configured with OnHostMaintenance: Migrate. However, that is not supported by GCP.

Could you rewrite the condition so this configuration is only accepted for AMD-SEV? (i.e. providerSpec.ConfidentialCompute == Enabled OR AMDEncryptedVirtualization)

[WTFKr0]

OK i see
Need this test to fail

		{
			testCase: "with ConfidentialCompute AMDEncryptedVirtualizationNestedPaging and onHostMaintenance set to Migrate on n2d instances",
			modifySpec: func(p *machinev1beta1.GCPMachineProviderSpec) {
				p.ConfidentialCompute = machinev1beta1.ConfidentialComputePolicySEVSNP
				p.OnHostMaintenance = machinev1beta1.MigrateHostMaintenanceType
				p.MachineType = "n2d-standard-4"
				p.GPUs = []machinev1beta1.GCPGPUConfig{}
			},
			expectedOk: true,
		},

[WTFKr0]

OK with last commit i think