SAM pipelines and deployment preferences

Exam alignment: DOP-C02 Domain 1 task statements for pipelines, testing, artifacts, or deployment.

Learning objective

Version serverless infrastructure and code together with progressive deployment and rollback.

Difficulty / Schwierigkeitsgrad	Intermediate
Study time / Lernzeit	120 minutes
Prerequisites / Voraussetzungen	Previous lessons in this volume

Professional scenario

Manual console changes cause function, API, permission, and alarm drift.

Core concepts

• SAM extends CloudFormation for serverless resources.
• Templates version code references, permissions, events, aliases, and preferences.
• AutoPublishAlias creates release versions.
• Pre/post-traffic hooks and alarms support validation and rollback.

Architecture flow

1. Identify the release input and immutable identity.
2. Select the managed AWS control plane and least-privilege role.
3. Execute build, test, artifact, or deployment work.
4. Collect service events, logs, reports, and runtime metrics.
5. Stop, retry, or roll back according to explicit rules.

Decision matrix

Requirement	Preferred choice	Reason
Code and infrastructure together	SAM	One reviewed model
Progressive Lambda release	DeploymentPreference	Managed traffic shift
Planned resource change	Change set	Review replacement risk

Failure modes and troubleshooting

• Template is YAML-valid but SAM-invalid.
• Hook timeout causes rollback.
• Generated IAM permissions are too broad.

Security and operations

• Use short-lived service roles and least privilege.
• Encrypt artifacts and protect logs from secret exposure.
• Record changes and approvals for audit.

Hands-on lab

Goal / Ziel: Deploy a SAM function with alias and canary preference.

Tasks

1. Create the smallest safe test architecture.
2. Implement or simulate the main workflow.
3. Introduce one controlled failure.
4. Diagnose it from service evidence.
5. Document cleanup and one improvement.

Validation

• The workflow uses an immutable version.
• A required failure blocks promotion.
• The diagnosis identifies the first failed transition.

Cost control / Kostenkontrolle: Keep resources short lived; read cleanup before starting.

Cleanup

1. Delete pipeline/build/deployment resources.
2. Delete temporary artifacts, images, logs, and roles.

Exam traps

• Changing Lambda outside IaC.
• Ignoring resource replacement.

Key takeaways

• SAM extends CloudFormation for serverless resources.
• Pre/post-traffic hooks and alarms support validation and rollback.
• Decisions must be justified by requirements and failure behavior.

Review questions

1. What is the immutable release identity?
2. Which evidence proves failure or success?
3. What is the safest recovery action?

Answers

1. A version, digest, or uniquely versioned artifact.
2. Service events, logs, reports, health checks, and runtime metrics.
3. Restore the known-good version using the configured rollback path.