Introduction 🚀
Jenkins, a leading automation server, offers various triggers to initiate builds automatically. One such trigger is Poll SCM, which enables Jenkins to periodically check for changes in the source code management (SCM) repository and trigger a build when changes are detected. In this article, we'll delve into the concept of Poll SCM in Jenkins, its configuration, benefits, and best practices.
What is Poll SCM?
Poll SCM is a build trigger in Jenkins that periodically checks the SCM repository for changes. When configured, Jenkins polls the SCM at regular intervals, comparing the current state of the repository with the last known state. If changes are detected, Jenkins triggers a build, ensuring that the latest changes are incorporated into the build process.
Configuring Poll SCM in Jenkins
To configure Poll SCM for a Jenkins job, follow these steps:
Open Job Configuration: Navigate to the configuration page of the job you want to trigger using Poll SCM.
Configure Build Triggers: In the job configuration, locate the "Build Triggers" section. Check the option for "Poll SCM".
Specify Polling Schedule: In the text field provided, enter the polling schedule using cron syntax. This schedule determines how often Jenkins checks for changes in the SCM repository. For example, to poll every 5 minutes, use the cron expression
H/5 * * * *
Save Configuration: Save the configuration changes for the job.
Now do some changes in the repository.
- Before build.
- In Poll SCM, Jenkins checks the repository every 5 minutes for new commits. If it finds any, it starts building the job.
Benefits of Poll SCM
Automatic Triggering: Poll SCM automates the process of triggering builds based on changes in the SCM repository, eliminating the need for manual intervention.
Timely Builds: By periodically checking for changes, Poll SCM ensures that builds are triggered promptly whenever changes are detected in the repository.
Efficient Resource Utilization: Poll SCM optimizes resource utilization by triggering builds only when necessary, reducing unnecessary builds and conserving resources.
Best Practices for Poll SCM
Optimize Polling Frequency: Fine-tune the polling schedule to balance responsiveness with resource utilization. Avoid polling too frequently, as it may strain the Jenkins server and SCM repository.
Use SCM Hooks (if available): Some SCM systems offer hooks that notify Jenkins of changes in the repository instantly, eliminating the need for polling. Whenever possible, use SCM hooks for more efficient triggering of builds.
Monitor Polling Activity: Regularly monitor the polling activity in Jenkins to ensure that builds are triggered promptly and efficiently. Adjust the polling schedule if necessary based on the project's requirements.
Conclusion 🌟
Poll SCM is a valuable build trigger in Jenkins that automates the process of triggering builds based on changes in the SCM repository. By configuring Poll SCM, users can ensure that builds are triggered promptly whenever changes are detected, streamlining the development workflow and ensuring timely delivery of software projects. By following best practices and optimizing the polling schedule, organizations can maximize the benefits of Poll SCM and enhance their CI/CD pipelines in Jenkins.