CI/CD cheatsheet

A one-page reference for CI/CD. For the Jenkins/GitLab CI deep-dives and full side-by-side comparison, see the complete guide.

📖 Full guide: CI/CD → 🟠Intermediate

⏱️Learn this in 5 minutes5 min

1. Begin with the Deployment strategies card
2. Then the GitHub Actions core concepts and Example workflow cards
3. Treat the other 3 cards as lookups — scan by card title when you need one
4. Open the full guide when a card isn't enough

Deployment strategies

Strategy	Idea
Rolling	replace instances gradually
Blue/green	switch traffic between two full environments
Canary	shift a small % of traffic first, watch metrics
Feature flags	ship dark, enable at runtime independent of deploy

GitHub Actions core concepts

• Workflow — YAML file under .github/workflows/.
• Job — runs on a runner, parallel by default unless needs: links them.
• Step — a command, or an action (reusable packaged unit).

Example workflow

name: CI/CD
on:
  push: { branches: [main] }
  pull_request:
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: npm ci && npm test

Secrets management

• Never hardcode secrets in pipeline YAML.
• Use the platform's secret store (GitHub Secrets, GitLab CI/CD variables, Vault).
• Scope secrets to the job/environment that needs them, not the whole repo.

Pipeline concepts

Trigger → Build → Test → Package → Deploy → Verify

Fail fast: cheap/fast checks (lint, unit tests) run before slow ones (integration, e2e) so bad commits are rejected quickly.

Common pitfalls

• No rollback plan — deploy strategy without a fast revert path.
• Flaky tests retried into passing instead of fixed — hides real signal.
• Secrets leaked into build logs via echo or verbose flags.
• One giant monolithic pipeline instead of composable, cacheable stages.

See: Common Pitfalls