Resolving Pods Stuck in Volume Unpublished Stage

Products

• VMware Tanzu Kubernetes Grid Integrated Edition

Issue/Introduction

This article aims to provide administrators and users with a comprehensive guide to troubleshoot and resolve situations where Pods remain stuck in the volume unpublished stage, specifically when the error Volume does not appear to be staged is observed. The article outlines steps to manually unmount the affected volume, ensuring the smooth functioning volume attachments.

Symptoms:

• The primary symptom addressed in this article is when Pods in a TKG environment are stuck in the volume unpublished stage. Users may encounter an error stating Volume does not appear to be staged upon describing the affected Pod.
• Secondary symptoms include failure of Pods to start or attach to their designated volumes properly.

Environment

Product Version: 1.16

Cause

The issue typically occurs when the device associated with the volume is not found during the unmount process. This can happen if the device is corrupted, has been removed, or otherwise becomes inaccessible, leading to the NodeUnpublish operation reporting success despite the volume being in an incorrect state. As a result, Kubernetes fails to transition the volume from the "staged" to "published" state, preventing the Pod from accessing its volume.

Resolution

1. Identifying the Mount Paths:
   • Use the volume identifier to find the mount paths for the volume. These include the globalmount and podmount paths.
   • The globalmount path is usually mentioned in the error when describing the affected Pod.
   • For the podmount path, use the command lsblk -l to list block devices and their mount points.
2. Manually Restarting CSI-node and Kubelet Processes:
   • To clear cache status and address the issue, manually restart the csi-node and kubelet processes on the node where the affected Pod is scheduled.
3. Unmounting the Volume:
   • Use the umount command followed by the mount paths identified in the first step to manually unmount the volume. The command should be executed as follows: umount [mount path].