Investigate sepecifying disk type/peformance in Prow

[serathius]

What would you like to be added?

Let's investigate if we can configure Prow to provide us disk with better performance. For etcd we recommend SSD, so for performance heavy tests we should use it.

I heard that Kubernetes Node tests run on VM, in that setup it should be possible to attach disk.
We should investigate how those test run.

Why is this needed?

Great for robustness and benchmarks to get stable performance

[kavirajk]

@serathius Checking the prow doc, looks like we can set some presets with volume that may use ssd based pvc? And we can add those presets in our Prow jobs for etcd here?.

Something like

volumes:
      - name: ssd-volume
        persistentVolumeClaim:
          claimName: ssd-pvc

New to Prow. Assuming this is where all the Prow jobs for etcd is stored?

[serathius]

And we can add those presets in our Prow jobs for etcd here?.

Should good, please coordinate with @ivanvc and @BenTheElder

New to Prow. Assuming this is where all the Prow jobs for etcd is stored?

Yes

[ivanvc]

@BenTheElder (or probably better to reach out in #sig-testing), could shed some light on what we need to do to define and have access to a PVC.

Should we worry that the PVC may become a bottleneck, as we may not have the pod schedule because it'll be waiting on the PVC? Unless we can create ephemeral PVCs, or alternatively, enable this only for periodic jobs.

[github-actions]

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[siyuanfoundation]

@serathius Do we still need this?

@BenTheElder Can you provide some guidance on the general practice to get a different disk type on prow?

[BenTheElder]

One option is spinning up an external VM to run the tests on, similar to how we spin up e2e test clusters on GCE/EC2.

We have actually moved prow on GKE to faster instances by default since this issue was filed. IIRC we're using C4 + hyperdisk now.