Scenario

A StatefulSet pod is stuck in Pending. kubectl describe pod says “0/3 nodes are available: pod has unbound immediate PersistentVolumeClaims”. The PVC is stuck in Pending state.

Question

What are the likely reasons the PVC is not binding?

Expected Answer

1. StorageClass: Does the StorageClass requested exist? Is the provisioner (e.g., EBS CSI driver) working?
2. Volume Binding Mode: If WaitForFirstConsumer is set, the PV won’t be created until the Pod is scheduled. If the Pod can’t be scheduled (e.g., due to taints/CPU limits), the PVC waits forever. Deadlock.
3. Availability Zone: If using AWS EBS/GCP PD, the PV might be created in us-east-1a, but the Pod is trying to run on a node in us-east-1b.
4. Capacity: The underlying storage backend (e.g., AWS quota) might be full/exceeded.