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Introduction

We would like to take some time and dive into the comparison of two very popular CI/CD tooling: GitHub Actions versus Jenkins. We often debate which one fits our needs more. Both have their pros and challenges, so I wanted to outline the key differences and share my thoughts on when and why you may choose one over the other.

Steps we will cover in this article:

• Overview of GitHub Actions
• Overview of Jenkins
• Example of a GitHub Actions Workflow
• Example of a Jenkins Pipeline
• Comparison and Commentary

Overview of GitHub Actions

GitHub Actions is a CI/CD tool in the cloud, tightly integrated with GitHub repositories. One of the biggest advantages to this is how simple it can be: it handles server management for you, and all you have to do is configure the workflows directly in your repository. It's also pretty easy to set up, even more so if your project is already in GitHub, since it reduces the headache of infrastructure.

Speaking of performance, GitHub Actions can be sluggish for some tasks, especially whenever a workflow is heavy-coupled with some build or packaging job involved. I find this to be true for cross-compiling Go containers or packaging macOS apps-these take a little longer than expected. You might want to take some of these issues into your own hands, though by using self-hosted runners; you can get a little more control over the hardware being used.

One weak point is the debugging of GitHub Actions. Sometimes logs or errors might not be so clear, and you need to struggle to figure out why one workflow fails. Once I was packaging a macOS app, and it was getting stuck at notarization without my being able to understand, and it took running a self-hosted runner on my own machine. The inability to reach an infrastructure level blocks GitHub Actions from having quicker troubleshooting.

However, one nice utility to overcome this problem is an open-source project called act. act runs your GitHub Actions workflows right on your machine, and it's much easier that way to debug and test changes before pushing to the repository. Since you would emulate the GitHub Actions environment right on your machine, you will receive immediate feedback, troubleshoot problems much faster, and not have to make continuous pushes to the GitHub repository just for testing your workflows.

That being said, GitHub Actions is about the best thing going for teams that want to reduce operational overhead managing CI servers and are looking for something very tightly integrated with GitHub. It's also got a lot of flexibility and scalability for smaller teams or projects looking to quickly spin up CI/CD pipes without a lot of overhead or complexity.

Overview of Jenkins

On the other hand, Jenkins is one of the oldest and most robust tools in the CI/CD ecosystem. It's an opensource tool that you self-host that gives you more control over its infrastructure, meanwhile allowing deeper customization. Jenkins has a huge ecosystem of plugins, allowing anything from simple builds up to more complicated workflows that may require custom logic to be run.

One of the most powerful features of Jenkins is how it is fantastically configurable and adaptable to just about any environment. You can create slave nodes that allow you to scale your CI/CD infrastructure horizontally. The flexibility comes at a cost, however: Jenkins and all the plugins that go with it can become a full-time job to manage. Long-running installations of Jenkins tend to gather a great number of interdependent plugins that are difficult and painful to upgrade and keep compatible. Often, one of the plugins will have an incompatibility issue, thus bringing other plugins down when upgraded, resulting in unscheduled/unplanned instances of downtime.

It also takes a person who can contribute knowledge in maintaining and scaling the infrastructure on the team.

That is not uncommon, and most large organizations run several instances of Jenkins to spread out the load for different teams and projects, which have very different plugin dependencies. This increases complexity, but this can be automated considering the fact that this is a relatively static installation. For small teams or projects, the overhead is probably not worth the differentiation when the level of customizations that Jenkins provides doesn't add much value. Another limitation involves the pipeline language, based on Groovy, that it uses. To some, this brings flexibility and to others, it brings too much complexity. This is because, due to the complexity of Groovy, shared libraries become painful to write and maintain across projects, and debugging pipelines written in Groovy is harder since they don't run as easily on a local machine. For example, you can't always execute the pipeline code directly from your terminal, making local development and testing slower.

Example of a GitHub Actions Workflow

Now, let's create a basic configuration for a GitHub Actions setup for a Node.js-based project. This will run on every push or pull request and then accomplish a series of tasks: installing the dependencies, running tests, and building the project.

.github/workflows/nodejs.yml

name: Node.js CI

on:
  push:
    branches:
      - main
  pull_request:
    branches:
      - main

jobs:
  build:
    runs-on: ubuntu-latest

    strategy:
      matrix:
        node-version: [14.x, 16.x, 18.x]

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Set up Node.js
        uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node-version }}

      - name: Install dependencies
        run: npm install

      - name: Run tests
        run: npm test

      - name: Build project
        run: npm run build

Example of a Jenkins Pipeline

Now, let’s look at the equivalent setup in Jenkins using a pipeline script. Jenkins uses Declarative Pipelines written in Groovy.

Jenkinsfile

pipeline {
    agent any

    environment {
        NODE_VERSION = '16.x'
    }

    stages {
        stage('Checkout') {
            steps {
                git 'https://github.com/your-repo/your-project.git'
            }
        }
        stage('Set up Node.js') {
            steps {
                sh "curl -sL https://deb.nodesource.com/setup_${NODE_VERSION} | sudo -E bash -"
                sh "sudo apt-get install -y nodejs"
            }
        }
        stage('Install Dependencies') {
            steps {
                sh 'npm install'
            }
        }
        stage('Run Tests') {
            steps {
                sh 'npm test'
            }
        }
        stage('Build') {
            steps {
                sh 'npm run build'
            }
        }
    }

    post {
        always {
            archiveArtifacts artifacts: '**/build/**', allowEmptyArchive: true
        }
        success {
            echo 'Build succeeded!'
        }
        failure {
            echo 'Build failed.'
        }
    }
}

Comparison and Commentary

This table summarizes the key differences and helps compare both tools side by side.

Aspect	GitHub Actions	Jenkins
Setup and Configuration	Easy to set up with minimal configuration. Integrated directly with GitHub repositories.	Requires manual setup of the server and pipelines. Greater control over the environment.
Performance	May encounter performance issues with larger or more complex workflows. Self-hosted runners can improve speed.	Can be highly optimized by configuring slave nodes and managing infrastructure resources.
Scalability and Flexibility	Works well out of the box, but may face limitations for large teams/projects. Self-hosted runners provide scalability.	Highly scalable with plugins and custom configurations. Ideal for large, complex environments.
Maintenance	Managed by GitHub, so no need for server maintenance, updates, or backups.	Requires ongoing maintenance, including updates, backups, and plugin management.
Cost	Free for public repositories and limited free minutes for private repos. Extra usage may incur costs.	Open-source but with hidden costs like infrastructure, maintenance, and server administration.
Ideal Use Case	Best for small to medium-sized projects needing a quick, easy-to-maintain solution.	Best for larger teams or projects requiring full control, customization, and scalability.

Conclusion

GitHub Actions vs. Jenkins: Neither of these tools is ultimately "better"; that really depends on what you're looking for. GitHub Actions is great for teams wanting something quick to set up, easy to manage, and pretty tight in its integration with GitHub. You will not need to concern yourself with maintaining a Continuous Integration server, and it's perfect for automating simple to moderately complex workflows. In that case, if you need more control over the environment and scaling also is a concern, then Jenkins might be the better choice.

For larger organizations or those requiring more customized enterprise CI/CD pipelines, Jenkins remains a great option. It is powerful and flexible; it handles very complicated workflows with ease. It certainly brings the cost of ongoing maintenance and infrastructure management, usually out-of-pocket.