A Jenkins pipeline is a group of events or jobs that are interlinked in a sequence. You can define a pipeline by creating a Pipeline object in your Jenkinsfile.
Parallel stages allow you to run multiple stages of a pipeline simultaneously. This can be useful if you have multiple stages independent of one another and can be run concurrently. For example, you might have a pipeline that builds and tests a software project and wants to run the build and test stages in parallel to save time.
In this article, we will explore Jenkins Parallel Stages and its benefits. We will also dive into the basics of parallel builds and how to use them in your projects.
Jenkins Parallel Block
We can define parallel actions in Jenkins using the parallel block. This stage contains a lists of nested stages that will be executed in parallel.
It is good to remember that a stage that runs in parallel should only contain one step, stage, or matrix. This means that you cannot have nested parallel blocks.
Example Usage
Let us take an example as shown below:
stages {
stage('Build') {
echo “Build Stage”.
}
stage('Test') {
echo “Build Stage”.
}
}
}
In this case, the pipeline will run the Build and Test stages sequentially. However, since neither of these stages relies on the results of a previous stage, we can run them in parallel, allowing us to save time, as shown in the pipeline below.
stages {
stage('Build') {
steps {
echo "Running stage: Build"
}
}
}
parallel {
stage('Test') {
steps {
echo "Running stage: Test"
}
}
stage('Deploy') {
steps {
echo "Running stage: Deploy"
}
}
}
}
This pipeline will run the Build stage first, then run the Test and Deploy stages in parallel, concurrently printing the current running stage for each stage.
Conclusion
The Jenkins parallel stage allows you to run multiple stages of a pipeline concurrently, which can help to speed up the overall execution of the pipeline.
You can use the parallel directive or the stages block to use parallel stages in a Jenkins pipeline. You can also specify the number of concurrent executions for each stage within the parallel block. By running stages in parallel, you can take advantage of available resources and parallelize the execution of independent stages, ultimately reducing the overall time it takes for the pipeline to complete.
