The cluster that won’t sail (Kubernetes troubleshooting)

The harbour master’s foreman watching the crew: who is working, who needs swapping out. This lesson is what the foreman does when a ship will not leave the dock and nobody knows why.

Before you start. Kubernetes is the harbour master: you hand it a written order (“two copies of this program, always”), and it keeps making that true. Each running copy is a pod, a ship in its berth, and a Service is the beacon at the port’s mouth that sends traffic to whichever pods wear its label (The Harbor Master (pods, deployments, services), Services & Ingress, from the inside). The foreman from Self-Healing & Autoscaling restarts ships that sink and pulls unfit ones out of the rotation. This lesson is what you do when all that machinery is running and the ship still is not sailing.