Concurrency

This page explains how to limit the number of concurrent PipelineRuns for a Repository CR and how to integrate with Kueue for Kubernetes-native job queueing. Use concurrency limits when you need to control resource consumption or prevent PipelineRuns from overwhelming your cluster.

Set the concurrency_limit field to define the maximum number of PipelineRuns running at any time for a Repository CR. This prevents resource exhaustion and ensures predictable scheduling when multiple events arrive in rapid succession.

spec:
  concurrency_limit: <number>

When multiple PipelineRuns match the event, Pipelines-as-Code starts them in alphabetical order by PipelineRun name.

Example:

If you have three PipelineRuns in your .tekton/ directory and you create a pull request with a concurrency_limit of 1 in the repository configuration, Pipelines-as-Code executes all PipelineRuns in alphabetical order, one after the other. At any given time, only one PipelineRun is in the running state, while the rest are queued.

For additional concurrency strategies and global configuration options, see Advanced Concurrency.

Kueue - Kubernetes-native Job Queueing

If you need more sophisticated queue management than concurrency_limit provides, Pipelines-as-Code supports Kueue as an alternative, Kubernetes-native solution for queuing PipelineRuns. To get started, deploy the experimental integration provided by the konflux-ci/tekton-kueue project. This allows you to schedule PipelineRuns through Kueue’s queuing mechanism.