CI/CD Pipeline Essentials

Understanding CI/CD

Continuous Integration (CI): Automatically test and integrate code changes. Continuous Deployment (CD): Automatically release tested code to production.

CI Pipeline Stages

1. Source Control

Code is committed to a repository (GitHub, GitLab, Bitbucket).

2. Build

Compile code, resolve dependencies, create artifacts.

npm install
npm run build

3. Unit Tests

Run automated unit tests to verify code correctness.

4. Code Quality

Check code style, coverage, and security issues.

SonarQube, ESLint, Prettier

5. Integration Tests

Test interactions between components.

CD Pipeline Stages

1. Staging

Deploy to staging environment for testing.

2. Approval (Optional)

Manual approval gate before production.

3. Production Deployment

Deploy to production using chosen strategy.

4. Smoke Tests

Quick tests to verify deployment success.

Deployment Strategies

Blue-Green Deployment

Maintain two identical environments, switch between them.

Canary Deployment

Gradually rollout to small percentage of users.

Rolling Deployment

Incrementally update instances, one at a time.

Popular CI/CD Tools

• GitHub Actions: Native GitHub integration
• GitLab CI/CD: Integrated with GitLab
• Jenkins: Flexible, widely used
• CircleCI: Cloud-native CI/CD
• Travis CI: Simple CI for open source

Best Practices

• Fast feedback loops (run quickly)
• Fail fast and notify immediately
• Automated testing throughout
• Version everything (code, config, infrastructure)
• Monitor and log pipeline executions
• Keep builds reproducible