Jenkins Pipeline Tutorial – Different Types of CI:CD Pipelines and Stages
Today, organizations constantly seek ways to optimize and automate their delivery processes. An open-source automation server, Jenkins has emerged as a powerful tool for orchestrating software delivery pipelines. With its flexible and extensible nature, Jenkins Pipeline allows teams to define and manage their software delivery workflows as code. It seamlessly fits into the DevOps practice and helps developers with hassle-free CI/CD.
This explains why, as of May 2022, more than 55900 companies use this Java-written platform. It has a market share of 51.35% in the continuous integration sector and continues to be at the helm.
That said, Jenkins Pipeline is one of the critical elements of Jenkins DevOps success.
What is Jenkins Pipeline?
Jenkins Pipeline is a collection of plugins that helps launch “build, test, and deploy” processes in a pre-defined sequence. The existence of over 1000 plugins within the Jenkins ecosystem means developers can opt for the best resources to execute and evolve CI/CD pipelines.
In essence, the Jenkins Pipeline consolidates a set of instructions that are essential for building and testing applications in a repeatable manner. The idea is to extend the CD practice capabilities, which aims to bring the software from version control to a user-facing release.
Why Use Jenkins Pipeline?
With Jenkins Pipeline, developers can create a robust, maintainable, and scalable development environment that fills the gap between release and production. As soon as the Jenkins Pipeline is implemented in the source control repository, it advocates for the creation of pipelines for each branch. It further creates audit trails by default and executes against any changes to the code for testing and deployment.
Jenkins Pipeline offers powerful automation for software delivery pipelines, providing benefits such as:
- Automation: Effortlessly automate the entire software delivery process, from build to deployment, reducing errors and ensuring consistent results.
- Flexibility: Customize pipelines to fit specific project requirements, workflows, and technology stacks.
- Reusability: Define pipelines as code for easy sharing and reuse across projects and teams, promoting collaboration and consistency.
- Visibility: Gain clear visibility into each stage and step of the delivery process, enhancing accountability and troubleshooting capabilities.
- CI/CD Support: Facilitate continuous integration and delivery practices with frequent code integration, automated testing, and seamless deployment.
Note: A single source of truth prevails for this pipeline so that everything is known, accessible, and editable at every point through time by project members.
Before we go any further, let's have a quick overview on
What is a CI/CD Pipeline?
A CI/CD pipeline is a sequence of steps necessary to deliver a new software version. It is a practice that emphasizes automating software delivery throughout the entire development lifecycle.
By automating CI/CD processes, including development, testing, production, and monitoring, organizations can achieve faster and higher-quality code development. While it is possible to manually execute each step of a CI/CD pipeline, the true value lies in the automation aspect.
Different Types of Jenkins CI/CD Pipelines
As mentioned earlier, Jenkins Pipeline is defined using a text file called the Jenkinsfile. It is implemented as code using the Groovy Domain-specific language, which can be edited either through an editor or the configuration page on the Jenkins instance. The Jenkinsfile provides developers with easy access and flexibility to modify and review the code as needed.
The Jenkins pipeline syntaxes are as follows–
-
- Declarative
- Scripted
While Scripted syntax and the associated Scripted pipelines have been around for some time, Declarative syntax and its associated Declarative pipelines are relatively new.
Scripted Pipeline
A scripted pipeline uses the Groovy (JVM-based) language to create a pipeline as code. Some software developers prefer this pipeline because the use of Groovy code paves the way for making numerous APIs available. As a result, developers can orchestrate rather complex CD pipelines.
For creating scripted pipelines in Jenkins, developers must include a pipeline code within the UI and save it. Here’s the general syntax of a scripted pipeline:
Jenkinsfile (Scripted Pipeline)
node {
stage('Build') {
…….
}
stage('Test') {
…….
}
stage('Deploy') {
…….
}
}
Source: Jenkins.io
Problems with scripted pipeline:
- The imbalance between developers’ experience in Groovy and Jenkins creates an impedance mismatch that is not easy to remove.
- Although scripted syntax is powerful and expedites the creation of complex pipelines, it concurrently makes the pipeline hard to read and hard to manage.
Declarative Pipeline
The declarative pipeline follows a relatively newer syntax, which narrows the scope of the pipeline structure through a pre-defined “minimum necessary structure.” On the technical front, the declarative syntax follows a conditional statement logic that generates a series of stages, executed sequentially throughout the pipeline’s lifecycle. Here’s the general syntax of a declarative pipeline:
Jenkinsfile (Declarative Pipeline)
pipeline {
agent any
stages {
stage(‘Build’) {
steps {
…….
}
}
stage(‘Test’) {
steps {
…….
}
}
stage(‘Deploy’) {
steps {
…….
}
}
}
}
Source: Jenkins.io
Problems with declarative pipeline:
- Since declarative pipelines don’t make use of Groovy code, the declarative syntax doesn’t access valuable APIs. But, at the end of the day, the declarative syntax is uncomplicated to read and comparatively easier to manage.
The Concept of Stages in Jenkins Pipeline
Jenkins defines two kinds of stages for declarative pipelines:
Parallel Stages
A nested, variable number of stages can be executed in parallel in declarative pipelines. This is a common and well-known use case for carrying out “build” and “test” across different platforms. Whenever there’s a problem in these parallel stages, the developer can abort them using the failFast option.
Sequential Stages
The sequential stages facility extends the capability of parallel stages by allowing for nesting multiple stages within each parallel branch. A sequential stage is an excellent choice when a developer would like more visibility into the sequence of stages and the order in which they are executed.
The nested stage facility in declarative pipelines makes it easier to follow the lifecycle of a pipeline. It also allows developers to view the set of logical states more profoundly. The good thing is that Jenkins evolves rapidly around stages, which is the core of CI/CD. So, the chances are that the coming improvements will further simplify the process of testing and deploying applications.
Integrate Test Automation with Jenkins
Test automation is integral to the DevOps philosophy, courtesy of its ability to speed up software development and bring forth the value of repeatability in a sophisticated development environment.
The CI/CD agile software development process fairs out in such a way that it brings with it the need to automate tests. Hence it’s here that the opportunity to tap into the power of test automation is increasingly tempting.
Considering Jenkins’ prowess in driving CI/CD, it’s a natural choice to integrate test automation with Jenkins.
ACCELQ provides a native Jenkins plugin to help run CI pipeline-specific automation scripts on Jenkins and get the best performance. Download here!
Reach out to us for more info.
Nidhi Achhaa | Content Specialist at ACCELQ
Nidhi specializes in technology-based content and strives to create a unique, customized, and compelling piece with a flavor of SEO. A writer with a love for words and a storyteller at heart.
