This article was last updated on January 8, 2025, to include insights on setting up hybrid workflows with GitHub Actions and Jenkins, optimizing costs with self-hosted runners, and avoiding common pitfalls like over-engineering pipelines or excessive cloud runner usage, along with practical tips for real-world CI/CD scenarios.

Introduction

TL;DR

Both GitHub Actions and Jenkins are powerful CI/CD platforms with their own strengths:

GitHub Actions: Cloud-hosted runners are available with pay-per-use pricing.

• Self-hosted runners for custom environments and cost control
• Native GitHub integration
• YAML-based configuration

Jenkins:

• Default self-hosted with full control
• Extensive plugin ecosystem
• Platform-agnostic integration
• Groovy-based pipeline configuration

Both of them also support self-hosted runners, which are workflows that you can run on your own infrastructure. It will all depend on your specific needs in terms of hosting, integration needs, and competencies within the team.

Having managed CI/CD pipelines for over a decade, I have worked a lot with GitHub Actions and Jenkins. Each of these platforms implements continuous integration in its own way, and the secret to choosing which one to use lies in understanding the capabilities each offers, especially regarding self-hosted runners and other options for customization.

Steps we'll cover:

• Introduction
• Understanding CI/CD Basics
• GitHub Actions Deep Dive
• Self-Hosted Runners: The Best of Both Worlds
• Jenkins in Detail
• Interactive Tool: Find Your Best Fit
• Real-World Comparison
• Community and Plugin Ecosystem
  • GitHub Actions Marketplace
  • Jenkins Plugin Ecosystem
  • Comparison of Extension Models
  • Key Differences
• Automated Migration with GitHub Actions Importer
  • Setting Up the Importer
  • Migration Process with the Importer
  • Supported Platforms
  • Pro Tips from My Experience
  • Common Conversion Patterns
• Cost Considerations
• Common Pitfalls to Avoid
• Conclusion

Understanding CI/CD Basics

Both GitHub Actions and Jenkins are based on similar principles of CI/CD but implemented in different ways. Whereas Jenkins was designed as a self-hosted solution right from the very beginning, GitHub Actions offers both cloud-hosted and self-hosted options. In this way, teams can have the flexibility they require while running their workflows.

Click to zoom

The main difference does not come in their capabilities, for both can be used to implement complex CI/CD workflows, but in how they handle hosting and configuration. Jenkins requires you to manage your own infrastructure from the very beginning, while GitHub Actions gives you an option between cloud-hosted runners-maintained by them-or self-hosted runners-you maintain yourself.

GitHub Actions Deep Dive

Let me share with you a simple GitHub Actions workflow that I use for Node.js projects:

name: Node.js CI

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  build:
    runs-on: ubuntu-latest
    
    steps:
    - uses: actions/checkout@v4
    - name: Use Node.js
      uses: actions/setup-node@v4
      with:
        node-version: '18.x'
    - run: npm ci
    - run: npm test

I love how GitHub Actions handles dependencies: it's like that smart assistant in your kitchen where you don't need to tell them where the flour or sugar is; it just knows.

Self-Hosted Runners: The Best of Both Worlds

While GitHub Actions is known for cloud runners, I have found that self-hosted runners can be a game-changer for many teams. Let me share my experience setting these up.

Why Consider Self-Hosted Runners?

1. Cost Control: An enterprise client of mine was able to reduce their GitHub Actions bill by 70% due to moving computationally expensive jobs to self-hosted runners.
2. Custom Hardware: Once I needed some specialized GPU instances for training ML models, which was a perfect use case for self-hosted runners.
3. Security Requirements: For teams working with sensitive data that can't leave their network.
4. Consistent Environment: When you want exactly the same environment as it would be in a production scenario.

Setting Up Self-Hosted Runners

Basic setup I use for self-hosted runners:

name: CI with Self-Hosted Runner
on: [push]

jobs:
  build:
    runs-on: self-hosted  # This is the key difference
    
    steps:
      - uses: actions/checkout@v4
      - name: Build
        run: ./build.sh

Pro Tips for Self-Hosted Runners

Leverage Labels Effectively:

jobs:
  gpu-job:
    runs-on: [self-hosted, gpu]  # Runner with specific capabilities

Hybrid Approach: Sometimes, I use both cloud and self-hosted runners in the same workflow:

jobs:
  tests:
    runs-on: ubuntu-latest  # Use GitHub-hosted for simple tests
  build:
    runs-on: self-hosted   # Use self-hosted for resource-intensive builds

Security Best Practices:

• Allow running workflows only from trusted repositories
• Provide updates constantly to runners
• Utilize a separate runner for each of the public and private repository.

Jenkins in Detail

Here is a similar pipeline in Jenkins:

pipeline {
    agent any
    
    tools {
        nodejs 'Node 18'
    }
    
    stages {
        stage('Build') {
            steps {
                sh 'npm ci'
            }
        }
        stage('Test') {
            steps {
                sh 'npm test'
            }
        }
    }
}

Jenkins is like having a restaurant of your own: more to keep, but you really can control literally everything. I once had to customize Jenkins' deployment to be to an air-gapped environment, and that would not have been even remotely possible inside GitHub Actions.

Interactive Tool: Find Your Best Fit

Not sure which tool is right for you? Try our interactive comparison tool:

Where is your code hosted?

Question 1 of 5

Real-World Comparison

Feature	GitHub Actions	Jenkins
Runner Options	Cloud-hosted and self-hosted	Self-hosted
Setting	YAML-based workflow files	Groovy-based Jenkinsfile
Setup Effort	Minimal for cloud, moderate for self-hosted	Moderate to high initial setup
Infrastructure	Managed (cloud) or self-managed (self-hosted)	Self-managed
Cost Structure	Pay-per-minute, cloud or self-hosted costs	INFRASTRUCTURE AND MAINTENANCE COSTS
Integration	Native GitHub, webhooks for others	Universal via plugins and webhooks
Customization	Actions marketplace, custom actions	Extensive plugin ecosystem, custom scripts
Security	GitHub-managed (cloud) or self-managed	Self-managed security and access control
Scaling	Automatic (cloud) or manual (self-hosted)	Manual configuration required
Learning Curve	Familiar for GitHub users, YAML knowledge	Jenkins-specific concepts, Groovy knowledge
Monitoring	GitHub-provided insights, custom monitoring	Plugin-based monitoring, custom solutions

Both are mature CI/CD solutions that can handle enterprise workloads. GitHub Actions offers more flexibility in hosting options, while Jenkins provides more granular control over the entire pipeline infrastructure.

Community and Plugin Ecosystem

GitHub Actions and Jenkins share good support for communities, yet both handle extensibility quite differently:

GitHub Actions Marketplace

• Actions: Over 20,000 Actions are ready for use and are publicly listed in the GitHub Marketplace
• Distribution: Operations are distributed as code repositories
• Versioning: Uses semantic versioning (v1, v2, etc.)
• Creation: Can be written in any language that runs in containers
• Sharing: Seamless integration with GitHub repositories
• Security: Scanning marketplace actions for vulnerabilities

Jenkins Plugin Ecosystem

• Plugins: Over 1,800 plugins are available in the Jenkins Plugin Index
• Distribution: Central plugin repository
• Versioning: Plugin-specific versioning w/ Jenkins version compatibility
• Creation: Primarily plugin development in Java
• Sharing: Sharing via Jenkins Plugin Repository
• Security: Community-maintained security advisories

Comparison of Extension Models

Aspect	GitHub Actions	Jenkins
Number of Extensions	20,000+ actions	1,800+ plugins
Extension Type	Individual task-focused actions	Feature-rich plugins
Development	Any language, containerized	Mainly Java
Installation	Referenced in workflow files	Installed on Jenkins server
Updates	Version specified in workflow	Centralized plugin manager
Scope	Mainly for the CI/CD related tasks	The complete feature set of Jenkins
Community Size	Large, GitHub-centric	Large, diverse enterprise community
Support	GitHub community, official GitHub support	Community forums, commercial support
Documentation	Standardized action documentation	Variable plugin documentation

Key Differences

• Architecture:

  • GitHub Actions: Modular composable actions
  • Jenkins: Monolithic plugins that can extend core functionality.

• Maintenance:

  • GitHub Actions: Low maintenance, version controlled in workflows
  • Jenkins: Requires regular plugin updates and compatibility management.

• Development:

  • GitHub Actions: Lowering the barrier of entry to making custom actions
  • Jenkins: More structured but complex plugin development process

• Integration:

  • GitHub Actions: Integrates seamlessly within the GitHub ecosystem.
  • Jenkins: More extensive integration via plugins

Automated Migration with GitHub Actions Importer

Let me share with you a game-changing tool I have been using lately: GitHub Actions Importer. This official GitHub tool has saved me so much time when migrating from other CI platforms to GitHub Actions.

Setting Up the Importer

First you will need to install the GitHub CLI extension:

gh extension install github/gh-actions-importer

Then upgrade to the latest version:

gh actions-importer update

Migration Process with the Importer

Here is my GitHub Actions Importer, step by step in using it.

1. Configure Credentials

gh actions-importer configure

This will prompt you for necessary credentials for both GitHub and your current CI platform.

2. Audit Your Current Pipelines

gh actions-importer audit jenkins --output-dir tmp/audit

This gives you a very detailed report about your pipelines and where conversions could be made.

3. Dry Run Conversions

gh actions-importer dry-run jenkins --target-url http://jenkins.internal:8080/job/example

I always do this before actual migration to catch any possible issues.

4. Execute the Migration

gh actions-importer migrate jenkins --target-url http://jenkins.internal:8080/job/example

Supported Platforms

I love how versatile this tool is. It supports migrations from:

• Jenkins perfect for this very comparison!
• CircleCI
• GitLab CI
• Azure DevOps
• Travis CI
• Bamboo
• Bitbucket Pipelines

Pro Tips from My Experience

• Start Small
  I always start with a simple, non-critical pipeline so that I can understand the patterns of conversion.

• Review Generated Workflows
  The tool is smart, but I always review the generated workflows. Sometimes I find opportunities for optimization.

• Manage Custom Scripts
  If you are using any custom scripts or plugins in Jenkins, get ready to adapt them manually. I usually create a list of these before starting.

• Test Everything
  I always run the old and new pipelines in parallel for a number of cycles at least after any migration to make sure everything works out identical.

Common Conversion Patterns

Here is a quick example of how Jenkins pipeline syntax gets converted to GitHub Actions:

// Jenkins pipeline
pipeline {
    agent any
    stages {
        stage('Build') {
            steps {
                sh 'npm ci'
                sh 'npm run build'
            }
        }
    }
}

Becomes:

# GitHub Actions workflow
name: Build
on: [push]
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Install dependencies
        run: npm ci
      - name: Build
        run: npm run build

Cost Considerations

Let me share with you a real story about costs. So, one of my clients was spending $2,000 a month on GitHub Actions when they could have run the same workloads on Jenkins for $500 a month in infrastructure costs. However, they saved $5,000 a month in engineering time not maintaining Jenkins!

Common Pitfalls to Avoid

• The "Lift and Shift" Trap
  Don't simply copy your Jenkins pipelines to GitHub Actions. They're different tools with different strengths.

• Scale Ignored
  GitHub Actions can be very expensive at scale. I learned this the hard way when our bill suddenly jumped 10x!

• Over-Engineering
  Keep it simple. I once spent a week building a complicated Jenkins pipeline for something that would've been 10 lines in GitHub Actions.

Conclusion

Having used a bit of both for several years, I know neither is universally "better." GitHub Actions is perfect for teams who need to move fast and don't mind paying for convenience. Jenkins is ideal for teams that need complete control and have the resources to maintain it.

Keep in mind that the best tool is the one that will suit your needs. Don't follow the trends; rather, think about your team's skills, budget, and requirements.

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