fix: update Hyperdisk attach limits to match GCP documentation for Ge… by arsiesys · Pull Request #2127 · kubernetes-sigs/gcp-compute-persistent-disk-csi-driver

arsiesys · 2025-07-09T01:25:07Z

What type of PR is this?

/kind bug

What this PR does / why we need it:
This PR updates the Hyperdisk balanced attach limits to align with the latest GCP documentation for Gen4 machine families (C4, C4D, N4, and C4A).
Previously, a single generic map was used, which did not reflect the correct per-family attach limits for newer machine types.

Key changes:

Adds separate Hyperdisk attach limit maps for C4, C4D, N4, and C4A machines.
Updates the attach limit calculation logic to use the appropriate map based on the machine type prefix.
Updates unit tests to cover new machine type mappings and verify correct limits.

This fixes inaccurate attach limits for Gen4 machines, ensuring compliance with the [official GCP guidance](https://cloud.google.com/compute/docs/general-purpose-machines).

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Please verify the machine type prefixes and limit values match the official GCP tables.

fix: Updated Hyperdisk balanced attach limits for C4, C4D, N4, and C4A machine families to match current GCP documentation.

k8s-ci-robot · 2025-07-09T01:25:16Z

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k8s-ci-robot · 2025-07-09T01:25:17Z

Hi @arsiesys. Thanks for your PR.

I'm waiting for a kubernetes-sigs 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.

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sunnylovestiramisu · 2025-07-09T15:53:19Z

/ok-to-test

sunnylovestiramisu · 2025-07-09T16:12:35Z

+	if len(limitMap) > 0 {
+		return limitMap[len(limitMap)-1].value
+	}
 	return 0


Do not think we should return 0 here, maybe use the default volumeLimitSmall.

I can return a static 15 as the constant is declared in node.go.
Or, I could move the constant from node.go to the common package, let me know which path we prefer.

sunnylovestiramisu · 2025-07-09T19:59:41Z

/test pull-gcp-compute-persistent-disk-csi-driver-e2e-windows-2022

sunnylovestiramisu · 2025-07-09T21:15:30Z

/assgn @mattcary

sunnylovestiramisu · 2025-07-09T22:51:23Z

-			return a4HyperdiskLimit, nil
-		}
+	}
+	if strings.HasPrefix(machineType, "x4-") {


Why moved this outside? Because if it is inside the machineType is x4 or a4 it does not need to go through the loop. But on the other hand it does not matter so much in the real world

You're right! Moving these checks outside was what I though could be a performance optimisation.

Since x4/a4 machine types don't match any of the gen4 prefixes (c4a-, c4-, n4-, c4d-), keeping them inside the loop means we'd unnecessarily check them 4 times (once per iteration) before ultimately returning the correct limit.

By moving them outside:

gen4 machines: Exit early when matched, never reaching these checks

Other machines: Only check x4/a4 once at the end

This reduces string comparisons from up to 12 (4 iterations × 3 checks) to at most 6 (4 gen4 + x4 + a4).

I also considered that x4 and a4 may be less frequently used than the ones in the loop. I will put it back if you think it would be better or not the subject of the current PR (would be understandable).

…n4 machines Signed-off-by: Loïc Yavercovski <loic.yavercovski@gmail.com>

sunnylovestiramisu · 2025-07-10T02:32:17Z

/lgtm
/approve

k8s-ci-robot · 2025-07-10T02:32:25Z

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: arsiesys, sunnylovestiramisu

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sunnylovestiramisu · 2025-07-10T17:52:38Z

/cherry-pick release-1.20

k8s-infra-cherrypick-robot · 2025-07-10T17:53:13Z

@sunnylovestiramisu: #2127 failed to apply on top of branch "release-1.20":

Applying: fix: update Hyperdisk attach limits to match GCP documentation for Gen4 machines
Using index info to reconstruct a base tree...
M	pkg/gce-pd-csi-driver/node.go
M	pkg/gce-pd-csi-driver/node_test.go
Falling back to patching base and 3-way merge...
Auto-merging pkg/gce-pd-csi-driver/node_test.go
CONFLICT (content): Merge conflict in pkg/gce-pd-csi-driver/node_test.go
Auto-merging pkg/gce-pd-csi-driver/node.go
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config advice.mergeConflict false"
Patch failed at 0001 fix: update Hyperdisk attach limits to match GCP documentation for Gen4 machines

Details

In response to this:

/cherry-pick release-1.20

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

…imits fix: update Hyperdisk attach limits to match GCP documentation for Gen4 machines

k8s-ci-robot added release-note Denotes a PR that will be considered when it comes time to generate release notes. cncf-cla: yes Indicates the PR's author has signed the CNCF CLA. labels Jul 9, 2025

k8s-ci-robot requested review from sunnylovestiramisu and tonyzhc July 9, 2025 01:25

k8s-ci-robot added the needs-ok-to-test Indicates a PR that requires an org member to verify it is safe to test. label Jul 9, 2025

k8s-ci-robot added the size/L Denotes a PR that changes 100-499 lines, ignoring generated files. label Jul 9, 2025

arsiesys mentioned this pull request Jul 9, 2025

Change Attach Limit to Hyperdisk Balanced Only #2126

Closed

k8s-ci-robot added ok-to-test Indicates a non-member PR verified by an org member that is safe to test. and removed needs-ok-to-test Indicates a PR that requires an org member to verify it is safe to test. labels Jul 9, 2025

sunnylovestiramisu reviewed Jul 9, 2025

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Comment thread pkg/common/constants.go Outdated

sunnylovestiramisu reviewed Jul 9, 2025

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arsiesys force-pushed the fix/hyperdisk-limits branch from 7b49535 to 6df040f Compare July 9, 2025 16:20

sunnylovestiramisu reviewed Jul 9, 2025

View reviewed changes

Comment thread pkg/common/constants.go Outdated

fix: update Hyperdisk attach limits to match GCP documentation for Ge…

d1ae089

…n4 machines Signed-off-by: Loïc Yavercovski <loic.yavercovski@gmail.com>

arsiesys force-pushed the fix/hyperdisk-limits branch from 6df040f to d1ae089 Compare July 9, 2025 23:41

k8s-ci-robot assigned sunnylovestiramisu Jul 10, 2025

k8s-ci-robot added the lgtm "Looks good to me", indicates that a PR is ready to be merged. label Jul 10, 2025

k8s-ci-robot added the approved Indicates a PR has been approved by an approver from all required OWNERS files. label Jul 10, 2025

k8s-ci-robot merged commit cb6ce0f into kubernetes-sigs:master Jul 10, 2025
9 checks passed

This was referenced Jul 10, 2025

fix: update Hyperdisk attach limits to match GCP documentation for Gen4 machines #2128

Closed

fix: update Hyperdisk attach limits to match GCP documentation for Gen4 machines #2129

Merged

chao007 mentioned this pull request Oct 23, 2025

STOR-2582: Rebase gcp-pd-csi-driver to v1.21.6 for OCP 4.21 openshift/gcp-pd-csi-driver#85

Merged

chaholl mentioned this pull request Apr 24, 2026

Hyperdisk attach limits should be discovered dynamically, not hardcoded in driver source #2307

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