This content originally appeared on DEV Community and was authored by Yusuf Ishola
As Kubernetes becomes the backbone of modern infrastructure, engineers are increasingly facing the challenges of managing PersistentVolumes (PV) and PersistentVolumeClaims (PVC) effectively. In this article, we’ll walk through a real-world scenario of troubleshooting a PVC stuck in a “Pending” state, sharing the insights and best practices that every DevOps engineer should know.
Understanding the Problem: PVC Stuck in “Pending” State
The Pending state of a PVC is often a bottleneck for engineers deploying stateful applications in Kubernetes. In our scenario, a PVC (devops-1-claim0) was failing to bind to its associated PV, with the following error:
Warning FailedBinding persistentvolume-controller volume “kt-migration-devops-1-pv” already bound to a different claim.
At first glance, this error might seem vague, but it points to a classic issue with Kubernetes’ PV lifecycle: the PV was in the Released state, preventing it from being re-bound.
The Root Cause: Understanding the “Released” State in Kubernetes
Kubernetes PVs follow a well-defined lifecycle:
Available: Ready for a PVC to claim it.
Bound: Attached to a PVC.
Released: The PVC is deleted, but the data on the PV remains, and the volume isn’t yet ready for another claim.
Failed: Something went wrong in the lifecycle.
In this case, the ReclaimPolicy for the PV was set to Retain, meaning that even after the original PVC was deleted, the data remained intact, and the PV was marked as Released. However, Kubernetes doesn’t automatically clean or make the volume available for reuse, leading to the binding failure.
Troubleshooting Steps: Clearing the “ClaimRef” Field
To resolve this issue, we needed to make the PV available again by clearing its ClaimRef, which was still pointing to the deleted PVC.
Check the PV’s Status: First, confirm the PV’s state and check if it’s in the Released state:
kubectl get pv kt-migration-devops-1-pv
Manually Clear the ClaimRef: The quickest way to reset the PV is by patching it to clear the old reference to the previous PVC:
kubectl patch pv kt-migration-devops-1-pv -p ‘{“spec”:{“claimRef”: null}}’
This effectively releases the PV for new claims, allowing the PVC to bind again.
Check the PVC Binding: Once the ClaimRef is cleared, check the status of the PVC:
kubectl get pvc -n kt-migration
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS VOLUMEATTRIBUTESCLASS AGE
devops-1-claim0 Bound kt-migration-devops-1-pv 300Gi RWO gp3 <unset> 2d4h
devops-2-claim0 Bound kt-migration-devops-2-pv 300Gi RWO gp3 <unset> 2d4h
devops-3-claim0 Bound kt-migration-devops-3-pv 300Gi RWO gp3 <unset> 2d4h
In our case, the PVC was successfully bound to the PV after clearing the ClaimRef.
Lessons Learned and Best Practices
This experience teaches several valuable lessons for managing stateful applications in Kubernetes:
Understand PV Lifecycles: As DevOps engineers, it’s crucial to understand how PVs move through their lifecycle. The Released state often trips engineers up when they expect Kubernetes to handle the cleanup automatically, especially with the Retain policy.
Monitor PVC and PV States: Keep an eye on both your PVC and PV states using kubectl describe to catch issues early. When a PVC gets stuck in Pending, don’t just focus on the PVC — check the associated PV to diagnose the problem.
Use Dynamic Provisioning When Possible: Static provisioning (pre-creating PVs) can lead to issues like this, where manual intervention is required to reset or clean up volumes. Whenever possible, rely on dynamic provisioning, where Kubernetes automatically creates and deletes volumes as needed.
Choose the Right Reclaim Policy: Be mindful of the ReclaimPolicy. In scenarios where data persistence is critical, Retain is the right choice. However, if volumes don’t need to retain data after the PVC is deleted, consider using Delete to avoid manual cleanup.
Persistent storage management in Kubernetes can be tricky, but understanding how PVs and PVCs interact will save you a lot of time and headaches. By sharing this real-world experience, I hope to help other engineers navigate similar issues with greater confidence and insight.
Kubernetes is powerful, but it requires a strong grasp of its underlying systems to ensure smooth deployments — especially in complex, stateful workloads like databases.
This content originally appeared on DEV Community and was authored by Yusuf Ishola
Yusuf Ishola | Sciencx (2025-02-09T18:41:15+00:00) Troubleshooting Kubernetes Persistent Volume Binding Issues.. Retrieved from https://www.scien.cx/2025/02/09/troubleshooting-kubernetes-persistent-volume-binding-issues/
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