GitHub actions vs. Jenkins for CI/CD Pipelines

There’s an age-old saying you can tell an engineer’s age by their preferred CI/CD (continuous integration and continuous delivery) tool. Depending on who you talk to, the battle-tested Jenkins remains their weapon of choice, while GitHub Actions is the new kid on the block turning heads.

However, here’s something that might surprise you – about half of all developers spend less than 20 hours per week on actual software development tasks. With such limited time, finding the right CI/CD tool becomes crucial for maximizing productivity. Since its initial release in 2018, GitHub Actions has significantly evolved, offering serious competition to Jenkins.

We’ll take a deep dive into these two popular CI/CD solutions, comparing their strengths, weaknesses, and use cases. By the end, you’ll have a clearer picture of which tool might best fit your team’s needs – or at least some ammunition for your next water cooler debate.

Image Source: Understanding GitHub Actions

What is GitHub Actions?

GitHub Actions is a CI/CD and automation platform integrated directly into GitHub repositories. It enables developers to automate software workflows in response to repository events. Workflows are triggered by repository events such as pushes, pull requests, or scheduled tasks. 

GitHub Actions is composed of three key components:

• Workflows: YAML files are stored in the .github/workflows directory of a repository. They define a set of events, jobs, and steps to be executed automatically.
• Actions: Reusable units of code that perform specific tasks within a workflow. Actions can be custom-built or sourced from the GitHub Marketplace.
• Runners: Virtual machines that execute workflows. GitHub provides hosted runners (Ubuntu, Windows, and macOS), and users can set up self-hosted runners for custom environments.

What is Jenkins? 

Jenkins is an open-source automation server that has been a huge player in the CI/CD space since its inception in 2011. Originally forked from the Hudson project, Jenkins has evolved into a powerful and flexible tool for building, deploying, and automating software projects.

Jenkins can be configured for high availability (HA) using active standby setups or clustering solutions. This ensures continuous operation even in the event of hardware failures or during maintenance windows, a critical feature for enterprises running mission-critical pipelines.

The longevity and adaptability of Jenkins have cemented its position in enterprise environments. Its steep learning curve is often offset by its powerful capabilities, which explains why your team lead continues to advocate for it. 

Core Features of GitHub Actions

GitHub Actions offers robust features that make it a compelling choice for CI/CD pipelines. It includes tight GitHub integration and pre-built actions from the GitHub Marketplace, making it easier for developers to streamline their workflows. It is particularly valuable in environments like Python development, where incorporating static code analysis can help catch vulnerabilities early, ensuring your code remains secure throughout the development process.

Flexible Runners

GitHub Actions provides a variety of runner options to execute your workflows:

• GitHub-hosted runners: These are managed virtual machines (Ubuntu, Windows, and macOS) maintained by GitHub. They come pre-installed with a wide range of software and tools, saving you the hassle of setup and maintenance.
• Self-hosted runners: For specific needs or enhanced control, you can set up your own runners on your infrastructure.

This flexibility allows teams to choose the most suitable environment for their builds.

Reusable Workflows

GitHub Actions allows you to create reusable workflows that can be shared across multiple repositories, making automation more efficient. This feature is especially useful when dealing with tasks like API automation testing, where workflows can handle repetitive processes seamlessly.

Extensive Marketplace

The GitHub Marketplace offers a vast collection of pre-built actions, with thousands of actions created by the community and verified partners. The GitHub actions marketplace significantly reduces the time and effort required to set up common CI/CD tasks. You can quickly incorporate best practices and integrate with popular tools without starting from scratch. An example of a common task you might be tasked with is integrating vulnerability scanning into your CI/CD pipeline, using Spectral GitHub action to scan your code directly in your pipeline.

Core Features of Jenkins

Jenkins has been in the CI/CD space for over a decade, offering a robust set of features catering to a wide range of development needs. Here are some of its core features: 

Pipeline as Code

Jenkins supports defining pipelines as code using a domain-specific language (DSL). Using a Jenkinsfile: you can define your entire build pipeline in a single file that can be versioned with your project. 

Jenkinsfiles are written using a Groovy-based DSL, Using a scripting language allows you to create complex and dynamic pipelines as well as shared libraries to create reusable pipeline components across multiple projects.

Community 

Jenkins has a large, active community that provides extensive support, with frequent releases of new features and security patches. The strong community support means that you’re likely to find solutions to common problems quickly.

For instance, if you’re struggling with a complex pipeline setup, you can often find similar use cases and solutions in the Jenkins community forums.

Flexibility and Plugin Ecosystem

Jenkins, much like GitHub Actions, provides a flexible plugin ecosystem, allowing for extensive customization. This flexibility is crucial in managing complex pipelines and ensuring secure development practices, especially when conducting a software supply chain risk assessment to mitigate vulnerabilities across dependencies.

Image Source: GitHub vs Jenkins | Which CI/CD tools is right to choose?

Pros and Cons of GitHub Actions and Jenkins

When choosing between GitHub Actions and Jenkins for your CI/CD pipeline, it’s crucial to understand their respective strengths and weaknesses. Here a some pros and cons of both:

Advantages of GitHub Actions

1. Low Barrier to Entry: GitHub Actions offers a seamless setup process with no hardware constraints. You can start building your CI/CD pipeline immediately without worrying about infrastructure. This is ideal for startups or small teams who want to implement CI/CD quickly without complexity or upfront infrastructure costs.
2. Tight GitHub Integration: As a native GitHub feature, Actions integrates smoothly with repositories, issues, and pull requests perfect for teams already using GitHub for source control, as it provides a unified platform for code and CI/CD.
3. Managed Infrastructure: GitHub Actions provides managed infrastructure that can reduce maintenance overhead, making it ideal for teams without dedicated DevOps resources. This is particularly useful when adopting practices like TDD with AI, where automation plays a central role in ensuring efficient and reliable test creation.
4. Marketplace Ecosystem: The GitHub Marketplace offers a wide array of pre-built actions, enabling quick integration of common tools and services.

Advantages of Jenkins

1. Mature Plugin Ecosystem: Jenkins boasts an extensive collection of plugins developed over many years, offering integrations with almost any tool or service. Ideal for organizations with complex, custom build processes or those using specialized tools.
2. Full Control and Customization: Jenkins provides full control over the CI/CD environment, which is particularly useful for organizations needing to secure their software supply chains. In high-security environments, understanding the implications of threats such as the XZ attack is critical to maintaining the integrity of your CI/CD pipeline.
3. Air-gapped Environments: Jenkins can operate in wholly isolated networks, making it suitable for high-security setups—a good use case for financial institutions or government agencies with strict data isolation requirements.
4. Jenkins offers advanced scaling capabilities, which are beneficial for larger organizations managing distributed CI/CD workloads. Effective scaling often involves implementing data governance tools to maintain control and security across the development pipeline.

Cons of GitHub Actions

1. Limited Customization: While flexible, GitHub Actions may not offer the same level of fine-grained control as Jenkins for complex scenarios, this could be a limitation for organizations with highly specialized build processes or unique compliance requirements.
2. Potential Vendor Lock-in: Deep integration with GitHub might make it challenging to migrate to other platforms in the future.
   • Use Case: A concern for companies that want to keep their options open for future changes in their development ecosystem.
3. Usage Limits and Costs: GitHub Actions has usage limits, and exceeding them can result in additional costs.
   • Use Case: May become expensive for large projects with frequent builds or long-running jobs.
4. Less Suitable for Non-GitHub Projects: While possible to use with external repositories, GitHub Actions is most effective with GitHub-hosted projects.
   • Use Case: Could be a drawback for teams using multiple version control systems or self-hosted Git repositories.

Cons of Jenkins

1. Setup and Maintenance Overhead: Jenkins requires careful consideration of hardware requirements and continuous maintenance. This can be a significant drawback for small teams or those without dedicated operations teams.
2. Security Responsibility: Users are responsible for patching vulnerabilities on their Jenkins server, which is a real concern as Jenkins is no stranger to critical vulnerabilities. 
3. Steeper Learning Curve: Jenkins’ flexibility comes at the cost of complexity, which can be overwhelming for beginners, this might slow down adoption in teams new to CI/CD or those with limited DevOps experience.
4. Resource Intensive: Jenkins can be resource-hungry, especially when running multiple concurrent jobs. This can lead to performance issues or increased infrastructure costs for organizations. 

Securing your Delivery

Without a doubt, GitHub Actions and Jenkins both offer compelling features that make them excellent choices for your continuous delivery needs. In this post, we highlighted many of them; beyond choosing a CI/CD tool, it is essential to secure the code going through your pipelines. 

This is where Spectral comes in, providing integrations for both Jenkins and GitHub actions, enabling you to catch vulnerabilities before they make it into production.