Nested and parallel stages in Jenkins pipelines
Summarize
Summary of Nested and parallel stages in Jenkins pipelines
ServiceNow DevOps supports the use of nested and parallel stages in scripted Jenkins pipelines to automate and accelerate pipeline execution. This feature enables teams to run multiple tasks simultaneously, such as different quality checks across operating systems and browsers, reflecting the real-time pipeline state within the ServiceNow DevOps pipeline UI. However, this support is limited to scripted pipelines; freestyle pipelines will still display stages sequentially despite parallel or nested configurations in Jenkins.
Show less
Key Features
- Real-time Pipeline UI Integration: The DevOps pipeline UI replicates the Jenkins UI, showing the current state of nested and parallel stages, including artifacts, test results, software quality summaries, and change request details.
- Change Requests for Nested and Parallel Stages: Change requests are created for each nested and parallel stage once all upstream events are complete, improving granularity and tracking beyond previous releases that only processed parent stages.
- Pipeline Structure Example: Supports complex pipeline definitions with nested parallel stages, allowing for better organization and execution of tasks like unit tests, integration tests, and additional nested parallel tests.
- Pipeline Execution Control: Pipelines pause execution if subsequent steps depend on change request approval, resuming automatically once approved.
Key Outcomes
- Faster pipeline execution through parallelization and better task organization.
- Improved visibility and management of pipeline stages and associated change requests at a granular level.
- Accurate reflection of Jenkins pipeline states within ServiceNow DevOps, enhancing monitoring and control.
- Requirement to map approval groups appropriately to nested and parallel stages to ensure correct approval workflows.
Upgrade Considerations
- Perform upgrades during off-peak hours to avoid interference with active pipeline executions.
- Ensure no pipeline executions are in progress during upgrade to prevent missing step executions.
- Rerun pipelines post-upgrade to generate correct step executions for nested and parallel stages.
Use nested and parallel stages in scripted Jenkins pipelines to speed up your pipeline execution. Change requests are created for nested and parallel stages and not just for the parent stage.
Support for nested and parallel stages in Jenkins pipelines
You can use nested and parallel stages in scripted Jenkins pipelines to automate and speed up tasks that can be run in parallel. For example, you have a scripted Jenkins pipeline with nested and parallel stages for various test cases such as different quality checks for different operating systems and browsers.
pipeline {
agent any
stages {
stage('Build') {
steps {
echo 'Building...'
// Your build steps here
}
}
stage('Test') {
parallel {
stage('Unit Tests') {
steps {
echo 'Running unit tests...'
// Your unit test steps here
}
}
stage('Integration Tests') {
steps {
echo 'Running integration tests...'
// Your integration test steps here
}
}
stage('Additional Tests') {
steps {
script {
parallel(
'Nested Stage 1': {
echo 'Running nested parallel stage 1...'
// Your nested parallel stage 1 steps here
},
'Nested Stage 2': {
echo 'Running nested parallel stage 2...'
// Your nested parallel stage 2 steps here
}
)
}
}
}
}
}
stage('Deploy') {
steps {
echo 'Deploying...'
snDevOpsChange changeRequestDetails: '{ "attributes": {"chg_model": "e55d0bfec343101035ae3f52c1d3ae49","standard_change_template"="563504cc47410200e90d87e8dee490e2"},"autoCloseChange": false}',changeStepTimeOut: 18000, pollingInterval: 60
// Your deploy steps here
}
}
}
}
Change requests in nested and parallel stages
Change requests are created for all nested and parallel stages, once all upstream events (prior to the change request) are received. In previous releases, nested or parallel stages in Jenkins pipelines were not identified nor processed in ServiceNow DevOps. Only parent stages were identified and processed in a linear or sequential manner. If change requests existed as part of any nested and parallel stages, those change requests were ignored and a single change request was processed as part of the parent stage. When you run a new pipeline after upgrading, new steps and steps executions are created for nested stages.
Nested and parallel stages were not processed previously, and approval groups were mapped only to the parent stage. Because nested and parallel stages are identified during processing, you must verify that relevant approval groups are mapped to the appropriate nested or parallel stage. If subsequent steps of the pipeline are dependent on the change request's being approved, the pipeline execution is paused, and resumed when the change request is approved.
Upgrade Considerations
- Upgrade during off-peak hours.
- Ensure that you do not have any pipeline executions that are currently in progress by ServiceNow DevOps. If pipeline executions are being processed, step executions might not be created as expected for the in-progress pipeline runs. Rerun the pipeline to create appropriate step executions.