> ## Documentation Index
> Fetch the complete documentation index at: https://docs.coreweave.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Troubleshoot HPC Verification

> Diagnose HPC Verification controller scheduling issues and collect details for CoreWeave Support

Use this guide when [HPC Verification](https://docs.coreweave.com/platform/fleet-management/hpc-verification.md) tests don't start in a CoreWeave Kubernetes Service (CKS) cluster.

A controller that starts successfully doesn't confirm that a GPU test ran. The test still requires an idle Node with all GPUs available. Check the verification result in the [Node Details dashboard](https://cks-grafana.coreweave.com/d/ddbdicm9sw7c5x/node-details).

## The verification controller Pod stays Pending

If no tests start, check the controller Pod before changing Node taints. You need `kubectl` access to the cluster and permission to list Pods, get Pod details, and list events in the `cw-hpc-verification` Namespace.

**1. List the verification Pods**

```bash theme={"system"}
kubectl get pods -n cw-hpc-verification
```

Look for a Pod with `-ctrl-` in its name that remains `Pending`.

**2. Inspect the controller Pod's scheduling events**

Replace `[CONTROLLER-POD-NAME]` with the controller Pod's name:

```bash theme={"system"}
kubectl describe pod [CONTROLLER-POD-NAME] -n cw-hpc-verification
```

In `Events`, look for `FailedScheduling` messages that identify untolerated taints or unavailable resources.

**3. Contact Support if a customer-applied taint blocks the controller**

If a customer-applied `NoSchedule` taint blocks the controller, [contact CoreWeave Support](https://docs.coreweave.com/support.md) to check the controller configuration. Include the following details:

* Cluster name.
* Controller Pod name.
* Scheduling events.
* Approximate time of the verification request.

Existing workflows can retain an older controller configuration even after CoreWeave updates the workflow template.

Leave CoreWeave-managed taints unchanged. Don't delete verification workflows or Pods to retry a health check. Deleting an existing request doesn't guarantee a replacement request.

[Administrator](https://docs.coreweave.com/support/platform/tags/administrator.md)