1. Overview
Choosing the right Continuous Integration/Continuous Deployment (CI/CD) tool is important for streamlining development and deployment processes in software development. Two prominent tools in this space are GitLab CI and Jenkins. They offer powerful features for automating builds, tests, and deployments. However, they both cater to different needs and preferences.
Knowing the differences between GitLab CI and Jenkins can help us select the most suitable tool for our project requirements.
In this tutorial, we’ll explore the features of GitLab CI and Jenkins. Additionally, we’ll compare their capabilities to provide a comprehensive understanding of their strengths and differences.
2. GitLab CI
GitLab CI integrates seamlessly with GitLab, making it a popular web-based DevOps lifecycle tool. As a CI/CD tool, developers can automate building, testing, and code deployment.
Let’s break down the features of GitLab CI that make it stand out for CI/CD.
2.1. Version Control Integration
GitLab CI is tightly integrated with GitLab’s version control system. This integration simplifies the setup process since the CI/CD functionality is built into the same platform that hosts the code repository. With this in place, we can easily create and manage CI/CD pipelines directly from GitLab repositories.
For example, let’s consider a simple pipeline definition using GitLab CI configuration:
stages:
- build
- test
build_job:
stage: build
script:
- echo "Compiling the code..."
- gcc -o my_app my_app.c
test_job:
stage: test
script:
- echo "Running tests..."
- ./my_app --run-tests
We have configured a pipeline with two stages: build and test. The build_job compiles the code, while the test_job runs the test. This example demonstrates the seamless integration of GitLab CI with GitLab’s version control system. This ensures seamless and automated execution with every code commit.
2.2. Auto DevOps
It also offers Auto DevOps, a feature that automatically detects, builds, tests, deploys, and monitors applications based on best practices. In particular, it simplifies the CI/CD process by providing pre-configured CI/CD pipelines that work out of the box.
2.3. Container Registry
GitLab CI includes a built-in container registry. This feature allows us to build, store, and deploy Docker images seamlessly. Additionally, this integration makes it easier to manage Docker images and use them within CI/CD pipelines.
For example, let’s look at a pipeline that builds and deploys a Docker image:
stages:
- build
- deploy
build_job:
stage: build
script:
- docker build -t my-app:latest .
- docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
- docker push $CI_REGISTRY/my-group/my-project/my-app:latest
deploy_job:
stage: deploy
script:
- docker pull $CI_REGISTRY/my-group/my-project/my-app:latest
- docker run -d -p 80:80 my-app:latest
From the configuration setup, the pipeline builds a Docker image, pushes it to the GitLab container registry, and then deploys it.
2.4. GitLab Runners
GitLab CI uses runners to execute jobs. Runners are lightweight, agent-like processes that run the scripts defined in the .gitlab-ci.yml file. Furthermore, they can be shared with a project enhancing flexibility in managing build environments.
For example, let’s consider a job that requires a specific runner:
stages:
- test
test_job:
stage: test
script:
- npm install
- npm test
tags:
- docker
In this example, the job runs on a runner tagged with docker, ensuring it has the necessary environment.
2.5. Pipeline Visibility
GitLab CI offers robust pipeline visualization tools. Furthermore, we can easily view the status of each stage and job, see logs, and identify any failures. This feature enhances quick diagnoses and issue resolution:
For example, the GitLab CI/CD dashboard (source) provides a graphical representation of different pipelines, showing the progress and results of each stage.
2.6. Security and Compliance
In software development, security and compliance are important. GitLab CI offers out-of-the-box security scanning and compliance. It can automatically scan code for vulnerabilities and enforce compliance with security policies. It ensures applications adhere to best practices.
For example, let’s consider a pipeline that includes a security scanning stage:
include:
- template: Security/SAST.gitlab-ci.yml
stages:
- test
- security
sast:
stage: security
In the configuration, this pipeline uses GitLab’s Static Application Security Testing (SAST) template to scan for security vulnerabilities as part of the CI/CD process.
3. Jenkins
Jenkins is a widely used open-source automation server. Just like GitLab CI, we can build, test, and deploy applications. As a standalone CI/CD tool, Jenkins is highly extensible through its vast ecosystem of plugins. In particular, it allows customizations to fit specific needs. Additionally, it’s known for flexibility and robust functionalities, which support a wide range of software development workflows.
Let’s break down the features of Jenkins that make it a powerful tool for CI/CD.
3.1. Extensive Plugin Ecosystem
It’s one of Jenkins’s powerful features. Jenkins boasts over 1,500 plugins that extend its capabilities. The plugins integrate with various version control systems to deploy applications to different environments.
For example, let’s consider a pipeline that uses plugins for Git integration and Docker build:
pipeline {
agent any
stages {
stage('Checkout') {
steps {
git 'https://github.com/example/repo.git'
}
}
stage('Build Docker Image') {
steps {
script {
docker.build('my-app:latest')
}
}
}
}
}
In the configuration, the pipeline uses the Git plugin to check the code and the Docker plugin to build a Docker image.
3.2. Declarative and Scripted Pipelines
These are the types of pipelines offered by Jenkins. Declarative pipelines provide a simpler and more structured way to define CI/CD pipelines using a predefined syntax. Additionally, scripted pipelines are more flexible and controlled through Groovy scripts.
For example, let’s consider a simple declarative pipeline:
pipeline {
agent any
stages {
stage('Build') {
steps {
echo 'Building...'
sh 'make build'
}
}
stage('Test') {
steps {
echo 'Testing...'
sh 'make test'
}
}
}
}
The example illustrates the use of a declarative pipeline with two stages: Build and Test. From the pipeline, the structure is straightforward to read. Therefore, it makes it accessible for users with different levels of expertise.
3.3. Blue Ocean Interface
Jenkins provides the Blue Ocean Plugin. Additionally, this plugin offers a modern and user-friendly interface for creating, visualizing, and managing pipelines.
In particular, the feature simplifies pipeline creation with a visual editor and enhances pipeline visualization with intuitive graphical representations.
3.4. Pipeline as a Code
Jenkins promotes pipeline as a code functionality. In particular, pipelines are defined and versioned using code stored in the project repository.
For example, a Jenkinsfile store in the repository defines the pipeline configuration:
pipeline {
agent any
stages {
stage('Build') {
steps {
echo 'Building...'
sh 'make build'
}
}
stage('Test') {
steps {
echo 'Testing...'
sh 'make test'
}
}
}
}
Committing this Jenkinsfile to the repository ensures the pipeline configuration is consistent and traceable.
3.5. Distributed Builds
Jenkins supports distributed builds across multiple machines. By using Jenkins agents, jobs can be distributed to different nodes, allowing parallel execution and faster build times.
For example, let’s consider a Jenkinsfile that specifies different agents for different stages:
pipeline {
agent none
stages {
stage('Build') {
agent { label 'build-node' }
steps {
echo 'Building on build-node...'
sh 'make build'
}
}
stage('Test') {
agent { label 'test-node' }
steps {
echo 'Testing on test-node...'
sh 'make test'
}
}
}
}
The build stage of this configuration runs on a node labeled build-node, while the test stage runs on a node labeled test-node, demonstrating Jenkins’ ability to distribute tasks.
3.6. Community Support
Jenkins is an open-source project with numerous plugin ecosystems. Additionally, professional developers and engineers contribute to and support these plugins through community efforts.
4. Comparisons Between GitLab CI and Jenkins
Here are some comparisons between GitLab CI and Jenkins:
Features
GitLab CI
Jenkins
Version Control Integration
It’s integrated with GitLab’s version control system
It supports various version control systems such as Git, SVN, and more
Ease of Setup
Setup is simple with built-in CI/CD functionalities in GitLab
It requires separate installations and configurations, which can be complex
Auto DevOps
It provides out of the box CI/CD pipeline with auto DevOps
The pipeline needs to be manually configured
Container Support
It has a built-in container registry for seamless Docker integration
There is no built-in container registry. Supports Docker through plugins
Runners and Agents
It uses GitLab Runners to execute jobs
It uses Jenkins agents (nodes) to execute jobs
Scalability
It’s easily scalable with GitLab Runners
It’s highly scalable with master-slave architecture
Security and Compliance
It uses tools like SAST directly in the CI/CD process
It requires additional plugins for security scanning and compliance
Customization
It has limited customizations compared to Jenkins
It’s highly customized with a vast range of plugins and script capabilities
User Interface
It has an intuitive and modern UI integrated with GitLab
Blue Ocean plugin, which offers a modernized interface
5. Conclusion
In this article, we’ve explored the features and capabilities of both GitLab CI and Jenkins. Furthermore, by understanding their strengths and differences, we can decide which CI/CD tool best suits our project needs.
Finally, the choice between GitLab CI and Jenkins depends on specific requirements, ease of integration, and the desired level of customization.