[jenkins] Running stages in parallel with Jenkins workflow / pipeline

Please note: the question is based on the old, now called "scripted" pipeline format. When using "declarative pipelines", parallel blocks can be nested inside of stage blocks (see Parallel stages with Declarative Pipeline 1.2).

I'm wondering how parallel steps are supposed to work with Jenkins workflow/pipeline plugin, esp. how to mix them with build stages. I know about the general pattern:

parallel(firstTask: {
  // Do some stuff
}, secondTask: {
  // Do some other stuff in parallel
})

However, I'd like to run couple of stages in parallel (on the same node, which has multiple executors), so I tried to add stages like this:

stage 'A'
// Do some preparation stuff

parallel(firstTask: {
  stage 'B1'
  // Do some stuff
}, secondTask: {
  stage 'B2'
  // Do some other stuff in parallel
})

stage 'C'
// Finalizing stuff

This does not work as expected. The "do stuff" tasks are executed in parallel, but the parallel stages end immediately and do not incorporate the stuff they should contain. As a consequence, the Stage View does not show the correct result and also does not link the logs.

Can I build different stages in parallel, or is the "parallel" step only meant to be used within a single stage?

I have just tested the following pipeline and it works

parallel firstBranch: {
    stage ('Starting Test') 
    {
        build job: 'test1', parameters: [string(name: 'Environment', value: "$env.Environment")]
    }
}, secondBranch: {
    stage ('Starting Test2') 
    {
        build job: 'test2', parameters: [string(name: 'Environment', value: "$env.Environment")]
    }
}

This Job named 'trigger-test' accepts one parameter named 'Environment'

Job 'test1' and 'test2' are simple jobs:

Example for 'test1'

• One parameter named 'Environment'
• Pipeline : echo "$env.Environment-TEST1"

On execution, I am able to see both stages running in the same time

As @Quartz mentioned, you can do something like

stage('Tests') {
    parallel(
        'Unit Tests': {
            container('node') {
                sh("npm test --cat=unit")
            }
        },
        'API Tests': {
            container('node') {
                sh("npm test --cat=acceptance")
            }
        }
    )
}

that syntax is now deprecated, you will get this error:

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
WorkflowScript: 14: Expected a stage @ line 14, column 9.
       parallel firstTask: {
       ^

WorkflowScript: 14: Stage does not have a name @ line 14, column 9.
       parallel secondTask: {
       ^

2 errors

You should do something like:

stage("Parallel") {
    steps {
        parallel (
            "firstTask" : {
                //do some stuff
            },
            "secondTask" : {
                // Do some other stuff in parallel
            }
        )
    }
}

Just to add the use of node here, to distribute jobs across multiple build servers/ VMs:

pipeline {
  stages {
    stage("Work 1"){
     steps{
      parallel ( "Build common Library":   
            {
              node('<Label>'){
                  /// your stuff
                  }
            },

        "Build Utilities" : {
            node('<Label>'){
               /// your stuff
              }
           }
         )
    }
}

All VMs should be labelled as to use as a pool.

I think this has been officially implemented now: https://jenkins.io/blog/2017/09/25/declarative-1/