The document discusses lessons learned from an outage caused by the Kubernetes API server failing at Zalando. Key points: - An outage occurred when the API server was killed due to out of memory issues, disrupting the Kubernetes cluster. - This caused all routes to applications to be removed and healthchecks to fail, marking all nodes as unhealthy in the load balancer. - With all targets unhealthy, the load balancer sent traffic to all nodes, exacerbating the problem. - The failures highlighted fallacies in assuming a cloud provider is reliable and dependencies are clear. Testing and designing for failure is necessary for resilient systems.