feat: make planner use DGD Scaling Adapters

[julienmancuso]

Overview:

make planner scale DGD Scaling Adapters.

Now that DGDSA have been introduced, planner should use these adapters to scale up/down DGD services

Summary by CodeRabbit

• Improvements

  • Service scaling now uses an improved scaling mechanism with automatic fallback support.

• Tests

  • Expanded test coverage for service scaling scenarios, fallback behavior, and error handling.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[coderabbitai]

Walkthrough

The changes introduce a new update_service_replicas() method that scales services via DGDSA Scale subresource with a fallback to direct DynamoGraphDeployment patching on 404 errors. The existing update_graph_replicas() now delegates to this new method for backward compatibility. Comprehensive unit tests cover the primary DGDSA path, fallback behavior, error propagation, and API delegation.

Changes

Cohort / File(s)	Summary
DGDSA-based scaling implementation components/src/dynamo/planner/kube.py	Added update_service_replicas() that scales via DGDSA Scale subresource with fallback to _update_dgd_replicas() on 404. Updated update_graph_replicas() to delegate to the new method. Added docstrings and logging.
Test coverage expansion tests/planner/unit/kube.py	Replaced single test with five new test functions: test_update_service_replicas_uses_dgdsa_scale, test_update_service_replicas_fallback_to_dgd, test_update_service_replicas_propagates_other_errors, test_update_graph_replicas_calls_update_service_replicas, and test_update_dgd_replicas_directly.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

• Fallback logic verification: Ensure the 404 detection and fallback to DGD patching behaves correctly under edge cases
• Adapter name construction: Verify the lowercase adapter name format (graph_deployment_name-service_name.lower()) matches expected DGDSA naming conventions
• Test isolation: Confirm mocking of both DGDSA Scale API and DGD patch calls prevents cross-test contamination

Poem

🐰 With DGDSA's might, we scale services bright,
When scales don't exist, to the DGD we fight!
Five tests now dance in this scaling ballet,
Fallbacks and errors handled—hooray, hooray! 🎪

Pre-merge checks

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description is missing required sections: Details about the changes are vague, no specific files are identified for review, and no related issues are linked.	Add a detailed 'Details' section explaining the implementation changes, specify files to review in 'Where should the reviewer start', and link related GitHub issues using action keywords.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Title check	✅ Passed	The title 'feat: make planner use DGD Scaling Adapters' clearly describes the main change: updating the planner to use DGD Scaling Adapters for scaling services.

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[coderabbitai]

Actionable comments posted: 0

🧹 Nitpick comments (1)

components/src/dynamo/planner/kube.py (1)

135-144: Consider adding a runtime deprecation warning.

While the docstring marks this method as deprecated, consider adding a runtime warning to alert callers:

+import warnings
+
 def update_graph_replicas(
     self, graph_deployment_name: str, component_name: str, replicas: int
 ) -> None:
     """
     Update replicas for a service. Now uses DGDSA when available.

     Deprecated: Use update_service_replicas() instead for clarity.
     This method is kept for backward compatibility.
     """
+    warnings.warn(
+        "update_graph_replicas() is deprecated, use update_service_replicas() instead",
+        DeprecationWarning,
+        stacklevel=2
+    )
     self.update_service_replicas(graph_deployment_name, component_name, replicas)

📜 Review details

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between a473402 and e2cd6a1.

📒 Files selected for processing (2)

• components/src/dynamo/planner/kube.py (2 hunks)
• tests/planner/unit/kube.py (1 hunks)

🧰 Additional context used

🧠 Learnings (1)

📓 Common learnings

Learnt from: julienmancuso
Repo: ai-dynamo/dynamo PR: 1474
File: deploy/cloud/operator/internal/controller/dynamocomponent_controller.go:1308-1312
Timestamp: 2025-06-11T21:29:28.650Z
Learning: User julienmancuso expects replies in English; avoid switching languages unless explicitly requested.

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• GitHub Check: trtllm (amd64)
• GitHub Check: sglang (arm64)
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• GitHub Check: operator (amd64)
• GitHub Check: sglang (amd64)
• GitHub Check: vllm (amd64)
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• GitHub Check: operator (arm64)
• GitHub Check: Build and Test - dynamo

🔇 Additional comments (3)

components/src/dynamo/planner/kube.py (2)

118-133: LGTM!

The fallback implementation correctly patches the DGD's spec.services structure, and the logging provides clear visibility into the fallback path.

---

81-116: The implementation is correct. The patch_namespaced_custom_object_scale() method is a legitimate Kubernetes Python client API for patching Scale subresources of custom objects. The body format {"spec": {"replicas": replicas}} is the correct standard for Scale subresource updates, and the adapter naming convention with lowercase service names matches the operator's documented DGDSA naming pattern (e.g., sglang-agg-decode). The error handling correctly distinguishes between 404 (fallback to DGD) and other errors (propagate).

tests/planner/unit/kube.py (1)

79-167: Excellent test coverage!

The test suite comprehensively covers:

• Primary DGDSA Scale API path with correct lowercase adapter naming
• 404 fallback to DGD patching
• Non-404 error propagation without fallback
• Backward compatibility through deprecated method delegation
• Direct testing of the internal fallback method

The test assertions correctly verify API call parameters, fallback behavior, and error handling logic.

[tmonty12]

LGTM