CI/CD and Release Engineering
What the exam tests
CI/CD and Release Engineering tests pipeline design, artifact integrity, deployment strategies, and rollback. Expect trunk-based development, automated testing, blue/green and canary releases, feature flags, and supply-chain controls.
Core rules
- Build once, deploy many: produce an immutable artifact, store it in a registry, and promote the same digest across environments.
- Separate CI (build and test) from CD (deploy); gate production with automated tests and where required approvals.
- Choose a release strategy by risk: rolling for routine changes, blue/green for instant switch and rollback, canary for measured exposure.
- Instrument DORA metrics: lead time, deployment frequency, change-failure rate, and time to restore.
Worked example
A payment service deploys to 5% of traffic via a canary. The pipeline watches error rate and p95 latency for 10 minutes; if either breaches the baseline by 20%, it automatically shifts traffic back and marks the release failed. Reasoning: the canary limits blast radius; automated rollback removes human latency; the same artifact digest is promoted to 100% only after metrics pass.
Traps
Rebuilding the artifact per environment, producing different binaries and untested code. Manual hotfixes that bypass the pipeline. No rollback plan. Treating feature flags as a substitute for testing. Ignoring secrets scanning and SBOM generation.