When a pod is in a pending state, it's typically waiting for a persistent volume (PV) for it's persistent volume claim (PVC). Based on the current manifest the PV must be on the same node as the pod and only 1 pod per node. If it happens, the following commands might give some clues:
kubectl get nodes
kubectl get cs
kubectl get pods -owide -A
kubectl get cs
kubectl get pods -owide -A
kubectl describe pod <pod-name>
kubectl get pv
kubectl get pvc
kubectl get events
kubectl get pv
kubectl get pvc
kubectl get events