gem-devops-guidelines - Claude MCP Skill

# DevOps Guidelines

Apply only sections relevant to workload/provider/environment/acceptance criteria. Skip Docker, Kubernetes, mobile, production, rollback, health, feature-flag, security checks when not applicable.

## Deployment strategy

- Rolling (default): gradual, zero-downtime replacement.
- Blue-green: duplicate environments, atomic cutover, instant rollback, 2× infra.
- Canary: route small % first; requires traffic splitting.

## Docker

- Pin base-image tags (`node:22-alpine`); NEVER `:latest`.
- Multi-stage builds + non-root user. Copy deps first for caching.
- `.dockerignore`: `node_modules`, `.git`, tests. Define `HEALTHCHECK` + resource limits.

## Kubernetes

Configure startup, readiness, liveness probes with workload-appropriate initial delays/thresholds.

## CI/CD

- PR: lint -> typecheck -> unit -> integration -> preview.
- Main: build -> staging -> smoke -> production.

## Health and shutdown

- Simple: `GET /health` -> `{ "status": "ok" }`.
- Detailed: dependencies, uptime, version.
- Services MUST expose meaningful health + gracefully handle `SIGTERM` when workload requires it.

## Configuration

Use environment variables (Twelve-Factor), separated by environment. Validate at startup + fail fast. NEVER commit secrets or hard-code `NODE_ENV=production`.

## Rollback

- Kubernetes: `kubectl rollout undo`.
- Vercel: `vercel rollback`.
- Docker: redeploy previous pinned image.

## Feature Flags

- Lifecycle: create -> enable -> 5% -> 25% -> 50% -> 100% -> remove flag + dead code.
- Every flag MUST have owner, expiration, rollback trigger. Remove within two weeks.

## Checklists

- Pre-deploy: passing tests, code review, env vars, migrations, rollback plan.
- Post-deploy: healthy, monitored, old pods terminated, outcome documented.
- Production: passing tests; no hardcoded secrets; JSON logs; meaningful health; pinned versions; validated env vars; resource limits; TLS; CVE scan; CORS; rate limiting; CSP/HSTS/X-Frame-Options; tested rollback; runbook; on-call.
- Apply security/CVE checks to executable or security-sensitive workloads.

## Mobile Deployment

- EAS: `eas build:configure`; `eas build -p ios|android --profile preview`; `eas update --branch production`; `--auto-submit`.
- Fastlane: iOS `match`/`cert`/`sigh`/`pilot`; Android Gradle/`supply`.
- Credentials in env/secret storage, never Git. Automate iOS signing with `fastlane match`; use `keytool` + Google Play App Signing for Android.
- TestFlight: internal instant; external 90 days/100 testers. Google Play: internal/beta/production. Expect 1–7 days review.
- Rollback: EAS `eas update:rollback`; native release -> revert build; store release -> reduce phased rollout.