Jenkins to GitHub Actions path - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Jenkins?

Jenkins is an open-source automation server used to build, test, and deploy software automatically.

beginner

What is GitHub Actions?

GitHub Actions is a tool integrated into GitHub that automates software workflows like building, testing, and deploying code.

intermediate

Name one key difference between Jenkins and GitHub Actions.

Jenkins runs on your own servers or cloud, while GitHub Actions runs inside GitHub's cloud environment.

beginner

How do you define a workflow in GitHub Actions?

You define a workflow using a YAML file placed in the .github/workflows directory of your repository.

beginner

What is a Jenkinsfile?

A Jenkinsfile is a text file that contains the pipeline script to define Jenkins build steps.

Where do GitHub Actions workflows live in a repository?

A .github/workflows directory

B root directory

C src directory

D docs directory

GitHub Actions workflows are stored in YAML files inside the .github/workflows directory.

Which file defines a Jenkins pipeline?

A build.gradle

B Dockerfile

C Makefile

D Jenkinsfile

The Jenkinsfile contains the pipeline script for Jenkins automation.

What triggers a GitHub Actions workflow by default?

A Cron job on Jenkins server

B GitHub events like push or pull request

C Jenkins job trigger

D Manual server command

GitHub Actions workflows are triggered by GitHub events such as push or pull request.

Which of these is NOT a benefit of moving from Jenkins to GitHub Actions?

A Requires installing Jenkins plugins

B Built-in integration with GitHub repositories

C No need to manage your own build server

D Easier setup for simple workflows

GitHub Actions does not require Jenkins plugins; Jenkins does.

How do you run multiple steps in a GitHub Actions job?

A Use shell scripts only

B Create multiple Jenkinsfiles

C List steps under the job in the YAML file

D Add steps in the Dockerfile

In GitHub Actions, you list multiple steps under a job in the workflow YAML file.

Explain the main steps to convert a Jenkins pipeline to a GitHub Actions workflow.

Think about how Jenkinsfile stages translate into YAML steps and triggers.

Describe the advantages of using GitHub Actions over Jenkins for CI/CD.

Consider ease of use and infrastructure management.

Practice

1. What is the main difference between Jenkins and GitHub Actions in terms of where the automation configuration is stored?

easy

A. Both Jenkins and GitHub Actions store workflows only on external servers.

B. GitHub Actions stores workflow files inside the repository, Jenkins uses an external server.

C. Jenkins stores workflows inside the repository, GitHub Actions uses an external server.

D. Both Jenkins and GitHub Actions store workflows only inside the repository.

Solution

1. Step 1: Understand Jenkins workflow storage

   Jenkins typically stores job configurations on its own server, separate from the code repository.

2. Step 2: Understand GitHub Actions workflow storage

   GitHub Actions stores workflow YAML files directly inside the code repository under the .github/workflows directory.

3. Final Answer:

   GitHub Actions stores workflow files inside the repository, Jenkins uses an external server. -> Option B

4. Quick Check:

   Workflow location = repository for GitHub Actions [OK]

Hint: Remember: GitHub Actions config lives with your code [OK]

Common Mistakes:

• Thinking Jenkins stores configs in the repo
• Assuming GitHub Actions uses external servers only
• Confusing storage locations for both tools

2. Which of the following is the correct syntax to trigger a GitHub Actions workflow on a push to the main branch?

easy

A. on: push: branches: [main]

B. trigger: push main

C. event: push branch main

D. when: push to main

Solution

1. Step 1: Recall GitHub Actions trigger syntax

   The correct YAML syntax uses 'on:' followed by the event type and branches list.

2. Step 2: Match syntax to options

   on: push: branches: [main] matches the correct YAML format: 'on: push: branches: [main]'. Others are invalid YAML or incorrect keywords.

3. Final Answer:

   on: push: branches: [main] -> Option A

4. Quick Check:

   Trigger syntax = 'on:' keyword [OK]

Hint: GitHub Actions triggers start with 'on:' in YAML [OK]

Common Mistakes:

• Using 'trigger' instead of 'on' keyword
• Incorrect YAML indentation or keywords
• Confusing event names and branch filters

3. Given this GitHub Actions workflow snippet, what will happen when a pull request is opened?

on:
  pull_request:
    branches:
      - main
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v3
      - name: Run tests
        run: echo "Tests running..."

medium

A. The workflow runs only when a pull request targets the main branch.

B. The workflow runs on any pull request regardless of target branch.

C. The workflow runs only on push events, not pull requests.

D. The workflow will fail due to syntax errors.

Solution

1. Step 1: Analyze the trigger section

   The workflow triggers on pull_request events targeting the 'main' branch only.

2. Step 2: Understand job execution

   When a pull request is opened against 'main', the job runs the steps: checkout and echo test message.

3. Final Answer:

   The workflow runs only when a pull request targets the main branch. -> Option A

4. Quick Check:

   Trigger filters = pull_request on main branch [OK]

Hint: Check 'on:' and branch filters to predict workflow triggers [OK]

Common Mistakes:

• Assuming it runs on all pull requests
• Confusing push and pull_request triggers
• Thinking syntax is invalid when it is correct

4. You migrated a Jenkins pipeline to GitHub Actions but the workflow does not run on push events. Which is the most likely cause?

medium

A. The workflow file is named with a .json extension instead of .yml.

B. The Jenkinsfile syntax was copied directly into the GitHub Actions YAML.

C. The repository is private and GitHub Actions only works on public repos.

D. The workflow YAML file is not placed under the .github/workflows directory.

Solution

1. Step 1: Check workflow file location

   GitHub Actions requires workflow files to be inside the .github/workflows folder to detect and run them.

2. Step 2: Evaluate other options

   Copying Jenkinsfile syntax won't run but does not prevent detection; GitHub Actions works on private repos; file extension must be .yml or .yaml, but location is primary cause.

3. Final Answer:

   The workflow YAML file is not placed under the .github/workflows directory. -> Option D

4. Quick Check:

   Workflow location = .github/workflows folder [OK]

Hint: Put workflow files in .github/workflows folder [OK]

Common Mistakes:

• Ignoring file location importance
• Assuming Jenkinsfile syntax works in GitHub Actions
• Thinking GitHub Actions only runs on public repos

5. You want to convert a Jenkins pipeline that runs tests on multiple operating systems into a GitHub Actions workflow. Which approach correctly replicates this behavior?

hard

A. Create separate workflows for each OS and trigger them manually.

B. Use a single job with a shell script that switches OS environments inside the runner.

C. Use a matrix strategy in GitHub Actions to run jobs on ubuntu-latest, windows-latest, and macos-latest runners.

D. GitHub Actions does not support multiple OS testing; use Jenkins instead.

Solution

1. Step 1: Understand Jenkins multi-OS testing

   Jenkins pipelines can run parallel jobs on different OS agents to test across environments.

2. Step 2: Use GitHub Actions matrix strategy

   GitHub Actions supports a matrix strategy to run the same job on multiple OS runners like ubuntu-latest, windows-latest, and macos-latest automatically.

3. Final Answer:

   Use a matrix strategy in GitHub Actions to run jobs on ubuntu-latest, windows-latest, and macos-latest runners. -> Option C

4. Quick Check:

   Matrix strategy = multi-OS testing [OK]

Hint: Use matrix to test multiple OS in one workflow [OK]

Common Mistakes:

• Trying to switch OS inside one runner
• Creating many manual workflows instead of matrix
• Believing GitHub Actions lacks multi-OS support