Why Does kube-scheduler Fail to Start? A Step‑by‑Step Fix

Problem

In a Kubernetes cluster the kube-scheduler pod fails to start. The pod logs contain an error indicating that the container name is already reserved for a specific container ID, which prevents the pod from reaching the Running state.

Solution

1. Identify the conflicting container

Use the containerd client ctr in the Kubernetes namespace to locate the container ID reported in the log.

# List containers in the k8s.io namespace and filter by the ID
ctr -n=k8s.io containers list --quiet | grep <CONTAINER_ID>

Replace <CONTAINER_ID> with the ID from the log, for example

830ab0f0a4e17a39e2b1d254038f05bf84aa586e39da300a2a4cd97c77bab4f0

.

2. Clean up the conflicting container

2.1 Stop the task

# Kill the task associated with the container
ctr -n=k8s.io tasks kill 830ab0f0a4e17a39e2b1d254038f05bf84aa586e39da300a2a4cd97c77bab4f0

2.2 Delete the container

# Delete the container
ctr -n=k8s.io containers delete 830ab0f0a4e17a39e2b1d254038f05bf84aa586e39da300a2a4cd97c77bab4f0

3. Restart kubelet

# Restart the kubelet service to refresh node state
systemctl restart kubelet

4. Verify the pod status

# List pods in the kube-system namespace
kubectl get pod -n kube-system

# Show detailed information for the kube-scheduler pod
kubectl describe pod kube-scheduler -n kube-system

When the kube-scheduler pod reports Running, the issue is resolved.