Troubleshoot a Kubernetes pod stuck in Pending

A pod on a Kubernetes cluster never leaves the Pending state. Walk through how you find out why and how you fix it.

A good answer goes step by step from what the cluster tells you about the pod to the likely causes, and says how you would check each one and what you would change. The round this came from was a live troubleshooting conversation about Linux, Kubernetes and running production systems.