Question 1

What is CI/CD?

Accepted Answer

Continuous Integration (CI) automatically runs tests when code is pushed. Continuous Deployment (CD) automatically deploys when tests pass. Together they catch bugs early and make deployments routine, not risky.

Question 2

Should I use GitHub Actions or a separate CI tool?

Accepted Answer

GitHub Actions is excellent and free for public repos (2,000 min/month for private). Use it unless you need specific features of CircleCI, GitLab CI, or Buildkite. Keeping CI with your code repository is convenient.

Question 3

How do I start with CI/CD?

Accepted Answer

Start simple: run your test suite on every push. Add linting and type checking. Then add automatic deployment. GitHub Actions workflows are YAML files in your repo—copy examples for your framework and customize.

Question 4

What tests should I run in CI?

Accepted Answer

Unit tests, integration tests, linting, and type checking. Fast tests that catch common bugs. Save long-running tests (E2E, performance) for specific triggers. CI should complete in under 10 minutes ideally.

Question 5

How do I handle secrets in CI?

Accepted Answer

Never put secrets in code or workflow files. Use your CI platform's secrets manager (GitHub Secrets, CircleCI Environment Variables). Secrets are injected at runtime and never logged.

Question 6

What is a GitHub Actions workflow?

Accepted Answer

A YAML file defining when to run (on push, PR, schedule), what environment to use (Ubuntu, Node version), and what steps to execute (install deps, run tests). Stored in .github/workflows/ in your repo.

Question 7

How long should CI builds take?

Accepted Answer

Under 10 minutes is ideal—fast feedback keeps developers productive. Cache dependencies to speed up installs. Parallelize tests. If builds take 30+ minutes, developers will stop waiting and push broken code.

Question 8

Should I require CI to pass before merging?

Accepted Answer

Yes. Configure branch protection rules requiring status checks to pass. This prevents broken code from reaching main. The brief friction is worth the reliability.

Question 9

What is caching in CI?

Accepted Answer

Storing dependencies (node_modules, pip packages) between builds to speed up installs. GitHub Actions and other platforms support caching. Typically saves 1-5 minutes per build. Essential for faster feedback.

Question 10

How do I deploy automatically?

Accepted Answer

Add deployment steps that run after tests pass on main branch. Platforms like Vercel and Netlify integrate directly with GitHub for automatic deploys. Or use CI to trigger deployment via CLI or API.

Question 11

What is a deployment pipeline?

Accepted Answer

Sequential stages code goes through: build, test, deploy to staging, run E2E tests, deploy to production. Gates between stages ensure quality. More complex than basic CI/CD but safer for critical applications.

Question 12

How do I run different workflows for different branches?

Accepted Answer

Configure workflow triggers on specific branches. Run full tests on PRs, deploy to staging from develop branch, deploy to production from main. GitHub Actions supports complex branching logic.

Question 13

What are matrix builds?

Accepted Answer

Running the same tests across multiple versions (Node 18 and 20) or operating systems (Linux and Windows) in parallel. Ensures compatibility. GitHub Actions matrix strategy makes this easy.

Question 14

How do I debug failing CI builds?

Accepted Answer

Read the logs—errors are usually clear. Reproduce locally with the same commands. Check environment differences (Node version, environment variables). Add debug output if needed. Most failures are test flakiness or missing dependencies.

Question 15

What is a flaky test?

Accepted Answer

A test that sometimes passes and sometimes fails without code changes. Often caused by timing issues, external dependencies, or test pollution. Flaky tests erode CI trust. Fix them immediately or quarantine them.

Question 16

Should I run CI on every push or just PRs?

Accepted Answer

Run on both. PR runs validate code before review. Push runs catch issues that slip through (merge conflicts, missed runs). Main branch should always be green—run CI to ensure it.

Question 17

What is GitOps?

Accepted Answer

Using Git as the source of truth for deployments. Changes are made via PRs, merged to main, and automatically deployed. CI/CD enables GitOps. Popular for infrastructure and Kubernetes deployments.

Question 18

How do I handle database migrations in CI/CD?

Accepted Answer

Run migrations automatically during deployment, before the new app version starts. Test migrations on staging first. Have rollback procedures ready. Some teams require manual approval for production migrations.

I need continuous integration and automated testing

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