Node troubleshooting in Kubernetes - Mini Project: Build & Apply

Node troubleshooting in Kubernetes

📖 Scenario: You are a Kubernetes administrator. One of the worker nodes in your cluster is not ready. You need to check the node status, describe the node to find issues, and then get logs from the kubelet service to understand the problem.

🎯 Goal: Learn how to check node status, describe a node, and fetch kubelet logs to troubleshoot node issues in Kubernetes.

📋 What You'll Learn

Use kubectl get nodes to check node status

Use kubectl describe node to get detailed node info

Use journalctl -u kubelet to view kubelet logs on the node

💡 Why This Matters

🌍 Real World

Kubernetes clusters often have nodes that become NotReady due to network issues, resource exhaustion, or kubelet failures. Troubleshooting nodes quickly helps keep applications running smoothly.

💼 Career

Kubernetes administrators and DevOps engineers must know how to check node health and diagnose node problems to maintain cluster stability and performance.

1

Check the status of all nodes

Run the command kubectl get nodes to list all nodes and their status in the cluster.

Kubernetes

# Run kubectl get nodes to see node status
# Your code here

Need a hint?

This command shows all nodes and their current status like Ready or NotReady.

2

Describe the problematic node

Use kubectl describe node replacing <node_name> with the exact name of the node that is NotReady to get detailed information about it.

Kubernetes

kubectl get nodes
# Use kubectl describe node  to get detailed info about the NotReady node
# Your code here

Need a hint?

Look for the node name exactly as shown in the first command output.

3

Check kubelet logs on the node

On the problematic node, run journalctl -u kubelet to view the kubelet service logs and find any errors or warnings.

Kubernetes

kubectl get nodes
kubectl describe node worker-node-1
# Run journalctl -u kubelet on the node to check kubelet logs
# Your code here

Need a hint?

This command shows logs from the kubelet service which manages the node.

4

Display the first 20 lines of kubelet logs

Run journalctl -u kubelet -n 20 to display only the last 20 lines of the kubelet logs for a quick overview.

Kubernetes

kubectl get nodes
kubectl describe node worker-node-1
journalctl -u kubelet
# Run journalctl -u kubelet -n 20 to show last 20 lines of logs
# Your code here

Need a hint?

This command limits the output to the most recent 20 log lines for easier reading.