Scenario

You deploying a new replica set, but the pods are stuck in Pending state and are not being scheduled on any node.

Question

What are the possible reasons for this, and how would you investigate?

Expected Answer

1. Check Events:
   • kubectl describe pod <pod-name> to see scheduler events.
   • Common reasons: “Insufficient cpu”, “Insufficient memory”, “No node(s) available for zone”, “Taint/Toleration mismatch”.
2. Resource Quotas:
   • Check if the namespace has hit its resource quota.
3. Node Status:
   • kubectl get nodes to ensure nodes are Ready.
   • Check for taints on the nodes.