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Lab 2.2 - Analysis of Worker Nodes

Objectives​

By the end of this lab, you will be able to:

  • Inspect the Worker Nodes
  • Understand the role of kubelet
  • Analyze kube-proxy
  • Examine the Container Runtime

Prerequisites​

  • A working Kubernetes cluster
  • kubectl installed and configured
  • Access to the cluster

Exercise 1: Inspect the Nodes​

Step 1: List the Nodes​

# View all nodes
kubectl get nodes

# View details of a node
kubectl describe node <node-name>

# View nodes with more information
kubectl get nodes -o wide

Question: How many Worker Nodes do you have? What are their roles?

Step 2: Node Information​

# View labels of a node
kubectl get node <node-name> --show-labels

# View annotations
kubectl get node <node-name> -o jsonpath='{.metadata.annotations}'

Exercise 2: Analyze kubelet​

Step 1: Check kubelet​

# View system Pods related to kubelet
kubectl get pods -n kube-system | grep kubelet

# View events of a node
kubectl get events --field-selector involvedObject.name=<node-name>

Step 2: Node Metrics​

# View resource usage of a node
kubectl top node <node-name>

# View resource details
kubectl describe node <node-name> | grep -A 10 "Allocated resources"

Exercise 3: Analyze kube-proxy​

Step 1: Check kube-proxy​

# View the kube-proxy Pod
kubectl get pods -n kube-system -l k8s-app=kube-proxy

# View logs of kube-proxy
kubectl logs -n kube-system -l k8s-app=kube-proxy --tail=50

Step 2: Check the Services​

# List all Services
kubectl get services --all-namespaces

# View Endpoints of a Service
kubectl get endpoints <service-name>

Exercise 4: Container Runtime​

Step 1: Identify the Runtime​

# View node information (contains the runtime)
kubectl describe node <node-name> | grep "Container Runtime"

# View used images
kubectl get pods --all-namespaces -o jsonpath='{range .items[*]}{.spec.containers[*].image}{"\n"}{end}' | sort -u

Exercise 5: Pods on a Node​

Step 1: Assigned Pods​

# View all Pods on a specific node
kubectl get pods --all-namespaces --field-selector spec.nodeName=<node-name>

# Count Pods per node
kubectl get pods --all-namespaces -o wide | awk '{print $7}' | sort | uniq -c

Step 2: Used Resources​

# View resource usage by Pod
kubectl top pods --all-namespaces

# Filter by node
kubectl top pods --all-namespaces | grep <node-name>

Reflection Questions​

  1. How many Pods can run on each node?
  2. How does kubelet manage resources?
  3. What is the role of kube-proxy on each node?
  4. How is the Container Runtime used?

Cleanup​

No cleanup necessary.

Next Steps​

Lab 2.3: Monitoring System Components
Module 3: Pods and Deployments

Lab created on: December 2024