Headlamp Plugin for Kueue Helps Diagnose Pending Kubernetes Jobs

Diagnosing Pending Kubernetes Jobs

When a Kubernetes Job remains suspended, the issue might not be with Pod scheduling but with Kueue's admission process. Kueue determines if a Job can use requested resources based on queue policy, quota, and other factors. The new Headlamp plugin helps users investigate this initial admission phase.

Kueue Plugin for Headlamp

The alpha release of the Kueue plugin for Headlamp integrates Kueue admission tracing directly into the Headlamp UI. This allows users to start their investigation from the Workload, examine its condition message, and follow links through related Kueue resources like LocalQueue, ClusterQueue, ResourceFlavor, and Cohort.

This integration aims to simplify the diagnostic process, reducing the need to reconstruct admission paths using multiple command-line tools and large YAML objects.

Functionality and Requirements

The 0.1.0-alpha plugin provides read-only views for Kueue v1beta2 Cohorts, ClusterQueues, LocalQueues, ResourceFlavors, and Workloads. It does not add new create, edit, stop, resume, or delete workflows, but Headlamp's standard YAML and resource actions remain available based on user permissions.

To use the plugin, users need a Kubernetes cluster with Kueue installed, a Headlamp installation, and the 0.1.0-alpha Kueue plugin. The Kubernetes identity must have permissions to read the relevant Kueue resources.

Distinguishing Admission from Scheduling

The plugin helps differentiate between Kueue admission issues and standard Pod scheduling problems. If a Workload is not admitted, the investigation remains within the Kueue section of Headlamp. If the Workload is admitted but Pods are still pending, users can then move to Headlamp's normal Job and Pod views to inspect scheduler events.