OCM-23235 |fix: remove validation for hcp cluster nodes size

[marcolan018]

PR Summary

remove validation for hcp cluster nodes size

Detailed Description of the Issue

To support min_replicas=0, in issue https://redhat.atlassian.net/browse/OCM-21663, we had changed the validation on nodepool min_replicas size. This PR focuses on the min_replicas size validation during cluster creation.

Related Issues and PRs

• Jira: https://redhat.atlassian.net/browse/OCM-23235
• Fixes: #
• Related PR(s):
• Related design/docs:

Type of Change

• feat - adds a new user-facing capability.
• fix - resolves an incorrect behavior or bug.
• docs - updates documentation only.
• style - formatting or naming changes with no logic impact.
• refactor - code restructuring with no behavior change.
• test - adds or updates tests only.
• chore - maintenance work (tooling, housekeeping, non-product code).
• build - changes build system, packaging, or dependencies for build output.
• ci - changes CI pipelines, jobs, or automation workflows.
• perf - improves performance without changing intended behavior.

Previous Behavior

rosa create cluster ... --min-replicas=0 --max-replicas=3  --enable-autoscaling
E: hosted Control Plane clusters require a minimum of 2 nodes, but 0 was requested

Behavior After This Change

rosa create cluster ... --min-replicas=0 --max-replicas=3  --enable-autoscaling
I: Cluster 'test' has been created.

How to Test (Step-by-Step)

Preconditions

Test Steps

Expected Results

Proof of the Fix

• Screenshots:
• Videos:
• Logs/CLI output:
• Other artifacts:

Breaking Changes

• No breaking changes
• Yes, this PR introduces a breaking change (describe impact and migration plan below)

Breaking Change Details / Migration Plan

Developer Verification Checklist

• Commit subject/title follows [JIRA-TICKET] | [TYPE]: <MESSAGE>.
• PR description clearly explains both what changed and why.
• Relevant Jira/GitHub issues and related PRs are linked.
• Tests were added/updated where appropriate.
• I manually tested the change.
• make test passes.
• make lint passes.
• make rosa passes.
• Documentation was added/updated where appropriate.
• Any risk, limitation, or follow-up work is documented.

[openshift-ci]

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[marcolan018]

/retest

[marcolan018]

/hold

[olucasfreitas]

Two blocking issues: missing unit test coverage for the changed function, and an unaddressed side effect on the non-autoscaling code path.

[olucasfreitas]

MinReplicaValidatorOnClusterCreate has zero unit test coverage in helper_test.go. Existing tests only cover MinReplicaValidator (nodepool level, line 520-571). A behavior change to an untested function must not merge without tests.

Add a DescribeTable in helper_test.go covering at minimum:

• HCP: min_replicas=0 with valid privateSubnetsCount (pass)
• HCP: negative min_replicas (fail)
• HCP: exceeds 500-node limit (fail)
• HCP: min_replicas not divisible by privateSubnetsCount (fail)
• Classic: boundary cases for 180/249 node limits

[olucasfreitas]

This validator is also invoked for non-autoscaling --compute-nodes in cmd/create/cluster/cmd.go:2849. With this removal, rosa create cluster --compute-nodes=0 on HCP without autoscaling now passes client-side validation.

If 0 nodes without autoscaling is not a valid HCP configuration, scope this removal to the autoscaling path only — the Autoscaling field already exists on ReplicaSizeValidation and can gate the check.

If the server rejects it anyway, document that explicitly in the PR description so reviewers can verify.