fix(ecs): suppress shouldUseCircuitBreaker warning for DAEMON scheduling strategy services

[gingeekrishna]

Summary

Fixes #38102

The @aws-cdk/aws-ecs:shouldUseCircuitBreaker warning fires for Ec2Service with daemon: true, even though the ECS deployment circuit breaker does not apply to DAEMON services. The circuit breaker threshold is 0.5 × desiredCount (min 3), but DAEMON services have no desiredCount — they run one task per container instance. Following the warning's advice and setting circuitBreaker on a daemon service is meaningless, and the only way to silence the false positive today is acknowledgeWarning().

Root cause: BaseService guards the warning with !props.circuitBreaker && this.isEcsDeploymentController, with no check for the scheduling strategy. Ec2Service passes schedulingStrategy only in additionalProps, so BaseService never accounts for it.

Fix: Add additionalProps?.schedulingStrategy !== 'DAEMON' to the warning guard. This is consistent with how CDK already special-cases daemon mode in multiple other places (desiredCount validation, minHealthyPercent default/warning, availabilityZoneRebalancing check, placement strategy checks).

Changes

• base-service.ts: Skip shouldUseCircuitBreaker warning when schedulingStrategy is DAEMON
• ec2-service.test.ts: Add test asserting the warning is not emitted for daemon services

Test plan

• New test: does not suggest circuitBreaker for DAEMON scheduling strategy services — passes
• Existing tests: suggests using circuitBreaker if false set and suggests using circuitBreaker if true set — still pass (non-daemon replica services are unaffected)
• Existing daemon-related tests (minHealthyPercent, placement strategy, desiredCount validation) — unaffected

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds an exclusion so ECS “should use circuit breaker” warnings aren’t emitted for DAEMON services, and introduces a regression test covering the DAEMON case.

Changes:

• Add a DAEMON scheduling-strategy guard to the circuit breaker recommendation warning.
• Add a new unit test ensuring no circuit breaker suggestion is emitted for daemon EC2 services.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
packages/aws-cdk-lib/aws-ecs/test/ec2/ec2-service.test.ts	Adds coverage to ensure DAEMON services don’t get circuit breaker recommendation warnings.
packages/aws-cdk-lib/aws-ecs/lib/base/base-service.ts	Skips the circuit-breaker recommendation warning when scheduling strategy is DAEMON.

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[aws-cdk-automation]

The pull request linter fails with the following errors:

❌ Fixes must contain a change to an integration test file and the resulting snapshot.

If you believe this pull request should receive an exemption, please comment and provide a justification. A comment requesting an exemption should contain the text Exemption Request. Additionally, if clarification is needed, add Clarification Request to a comment.

✅ A exemption request has been requested. Please wait for a maintainer's review.

[gingeekrishna]

Exemption Request

This PR only suppresses a false-positive advisory annotation () for DAEMON scheduling-strategy services. It does not change any synthesized CloudFormation template, resource property, or deployment behavior — the only observable effect is that no longer emits a misleading warning for daemon services.

Integration tests verify infrastructure behavior via snapshot diffs; because no snapshot would change as a result of this fix, an integration test would add no signal beyond what the existing unit tests already cover.