Revert "feat: support graceful scale-down for AlluxioRuntime" (#5805)

[cheyang]

Why

PR #5805 introduced AlluxioRuntime graceful scale-down (decommission + drain logic) with unit tests only. It does not include an end-to-end test validating the actual scale-down → drain → decommission → data-integrity path under a real Kind cluster.

Since this feature changes runtime scaling behavior in a way that could cause silent data loss if the drain/decommission sequence doesn't work correctly in production, we are reverting until the contributor provides a matching test/gha-e2e/ scenario that exercises the full lifecycle.

What this reverts

Commit ec6072e — "feat: support graceful scale-down for AlluxioRuntime using AdvancedStatefulSet (#4193) (#5805)"

Removed files:

• pkg/ddc/alluxio/operations/decommission.go
• pkg/ddc/alluxio/operations/decommission_test.go
• pkg/ddc/alluxio/replicas_drain_test.go
• pkg/features/features.go

Reverted modifications:

• api/v1alpha1/status.go
• pkg/ddc/alluxio/const.go
• pkg/ddc/alluxio/replicas.go
• test/gha-e2e/curvine/read_job.yaml

Re-land path

@jakharmonika364 — once you add a Kind-based e2e test (under test/gha-e2e/) that validates AlluxioRuntime scale-down (reduce replicas → verify decommission completes → verify data integrity), please open a new PR containing both the feature and the e2e test. We'll fast-track the review.

cc @cheyang

[gemini-code-assist]

Code Review

This pull request removes the graceful worker scale-down feature for AlluxioRuntime, deleting its associated feature gate, decommissioning operations, status conditions, and unit tests. Additionally, it simplifies the read job command in the E2E test configuration. As there are no review comments, I have no feedback to provide.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 64.77%. Comparing base (ec6072e) to head (9232261).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6059      +/-   ##
==========================================
- Coverage   64.89%   64.77%   -0.12%     
==========================================
  Files         486      484       -2     
  Lines       34057    33892     -165     
==========================================
- Hits        22101    21954     -147     
+ Misses      10228    10215      -13     
+ Partials     1728     1723       -5     

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[jakharmonika364]

Thanks for flagging this - agreed the missing e2e coverage was a real gap. Re-land is up at #6061 with a Kind e2e test under test/gha-e2e/alluxio-scaledown/ covering scale-down → drain → decommission → data read, plus a fix for --feature-gates not being wired into the alluxio controller binary, which had made the gate unreachable. Happy to adjust further if you spot anything.

[RongGu]

/lgtm
/approve

[fluid-e2e-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: RongGu

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Details

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• OWNERS [RongGu]

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud