Fix PVC Resize Stuck or Failed

💡 Quick Answer: Debug PersistentVolumeClaim expansion failures. Covers allowVolumeExpansion, filesystem resize conditions, offline vs online expansion, and recovery from stuck resizes.

The Problem

This is a common issue in Kubernetes storage that catches both beginners and experienced operators.

The Solution

Step 1: Check Resize Status

kubectl describe pvc my-claim | grep -A5 "Conditions"
# Type: FileSystemResizePending
# Message: "Waiting for user to (re-)start a pod to finish resize"

Step 2: Enable Volume Expansion

# Check if StorageClass allows expansion
kubectl get storageclass standard -o jsonpath='{.allowVolumeExpansion}'
# Must be true

# Enable it
kubectl patch storageclass standard -p '{"allowVolumeExpansion": true}'

Step 3: Resize the PVC

# Edit PVC to increase size
kubectl patch pvc my-claim -p '{"spec":{"resources":{"requests":{"storage":"20Gi"}}}}'

# For offline-only resize (most block storage):
# 1. Scale down the pod
kubectl scale deployment myapp --replicas=0
# 2. Wait for resize to complete
kubectl get pvc my-claim -w
# 3. Scale back up
kubectl scale deployment myapp --replicas=1

Step 4: Stuck Resize Recovery

# If resize is stuck, check PV status
kubectl describe pv <pv-name> | grep -A5 "Conditions"

# For cloud providers, check the volume in the cloud console
# AWS: EC2 > EBS > Volumes > check "modification" state

# Nuclear option: recreate PVC with snapshot
kubectl get volumesnapshot

Best Practices

• Monitor proactively with Prometheus alerts before issues become incidents
• Document runbooks for your team’s most common failure scenarios
• Use kubectl describe and events as your first debugging tool
• Automate recovery where possible with operators or scripts

Key Takeaways

• Always check events and logs first — Kubernetes tells you what’s wrong
• Most issues have clear error messages pointing to the root cause
• Prevention through monitoring and proper configuration beats reactive debugging
• Keep this recipe bookmarked for quick reference during incidents