Control Plane

kube-apiserver Not Starting: Troubleshooting Guide The kube-apiserver is the heart of any Kubernetes cluster. If it doesn’t start, the entire control plane is effectively down — meaning kubectl and controllers won’t work. Let’s go through common causes and fixes. Symptoms kubectl commands fail with connection errors. In kubectl get pods -n kube-system, the kube-apiserver pod is CrashLoopBackOff or not running. Logs may contain messages like etcd connection refused, failed to listen on port 6443, or certificate errors. Common Causes and Fixes 1. Port Conflicts The API server binds to 6443 by default. If another process is already listening there, kube-apiserver won’t start. ...

kube-scheduler Not Starting: Troubleshooting Guide The kube-scheduler is a critical control plane component in Kubernetes. If it doesn’t start, pods cannot be scheduled to nodes — leaving them stuck in a Pending state. Here’s how to troubleshoot when the scheduler refuses to start. Common Symptoms kubectl get pods -n kube-system shows kube-scheduler CrashLoopBackOff or not running at all. Pods stay in Pending forever. Logs contain errors like failed to bind to port or etcd connection refused. Possible Causes and Fixes 1. Port Conflicts By default, kube-scheduler listens on 10259 (secured) and optionally 10251 (insecure). If another process is already using the port, scheduler won’t start. ...

Introduction Kubernetes is powerful, but what’s the brain behind all those kubectl commands? That role is played by the kube-apiserver — the front door to your Kubernetes cluster. Everything goes through it: creating pods, scaling deployments, checking health — you name it. Let’s break it down in a way that’s easy to understand. What is kube-apiserver? kube-apiserver is the central communication hub of Kubernetes. It exposes the Kubernetes API and handles: ...