CodeDeploy EC2 in-place deployments

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

Learning objective

Use AppSpec hooks, agents, healthy-host settings, and rollback for existing instances.

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

Professional scenario

A fleet accepts reduced capacity during release but needs automated host updates.

Core concepts

• In-place modifies current target instances.
• The CodeDeploy agent executes AppSpec lifecycle hooks.
• Deployment configuration controls minimum healthy hosts.
• Load balancer integration removes hosts during update.

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
Limited duplicate capacity	In-place	Uses current fleet
Availability control	Minimum healthy hosts	Controls concurrency
Validation	ValidateService plus alarm	Host and runtime evidence

Failure modes and troubleshooting

• Agent missing or offline.
• Instance profile cannot read revision.
• Hook script returns non-zero.

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 small revision and trigger one hook failure.

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

• Choosing in-place for strict immediate rollback.
• Impossible healthy-host percentage for small fleet.

Key takeaways

• In-place modifies current target instances.
• Load balancer integration removes hosts during update.
• 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.