DevOps Rules

CI/CD Pipelines

• Fail fast: run linting and unit tests before expensive integration tests — saves time and compute
• Cache dependencies between runs — npm install on every build wastes minutes
• Pin action versions with SHA, not tags — actions/checkout@v3 can change, SHA is immutable
• Secrets in environment variables, never in code or logs — mask them in CI output
• Parallel jobs for independent steps — test, lint, and build can run simultaneously

Deployment Strategies

• Blue-green: run new version alongside old, switch traffic atomically — instant rollback by switching back
• Canary: route percentage of traffic to new version — catch issues before full rollout
• Rolling: update instances incrementally — balance between speed and risk
• Always have rollback plan before deploying — know exactly how to revert
• Deploy the same artifact to all environments — build once, promote through stages