Unit 10 Lab - Kubernetes

If you are unable to finish the lab in the ProLUG lab environment we ask you reboot the machine from the command line so that other students will have the intended environment.

Resources / Important Links

Required Materials

  • Rocky 9.4+ - ProLUG Lab
    • Or comparable Linux box
  • root or sudo command access

Downloads

The lab has been provided for convenience below:

Pre-Lab: Quick Warmup and System Checks

Before installing K3s, verify system compatibility and gather initial data.

Step 1: Download and Inspect K3s Installer

curl -sfL https://get.k3s.io > /tmp/k3_installer.sh
more /tmp/k3_installer.sh

Questions:

  • What system checks does the installer perform?
  • What environment variables does it check?

Step 2: System Architecture Check

uname -m
grep -i arch /tmp/k3_installer.sh

Questions:

  • What is the variable holding the system architecture?
  • How does K3s determine system compatibility?

Step 3: SELinux Status Check

grep -iE "selinux|sestatus" /tmp/k3_installer.sh
sestatus

Questions:

  • Does K3s check if SELinux is enabled?
  • What are the implications of SELinux on Kubernetes deployments?

Installing K3s and Verifying the Service

Step 4: Install K3s

curl -sfL https://get.k3s.io | sh -

Step 5: Verify Installation

systemctl status k3s
systemctl is-enabled k3s
  • What files and services were installed?
  • Is K3s set to start on boot?

Step 6: Explore System Services

systemctl cat k3s
  • What startup configurations does K3s have?
  • Does it rely on any dependencies?

Exploring Kubernetes Environment

Step 7: Checking Kubernetes Components

kubectl version
kubectl get nodes
kubectl get pods -A
kubectl get namespaces
kubectl get configmaps -A
kubectl get secrets -A

Questions:

  • What namespaces exist by default?
  • What secrets are stored in the cluster?

Deploying Applications: Pods, Services, and Deployments

Step 8: Create a Simple Web Server Pod

kubectl run webpage --image=nginx
  • Verify pod creation: 
    kubectl get pods
kubectl describe pod webpage

Step 9: Deploy a Redis Database with Labels

kubectl run database --image=redis --labels=tier=database
  • Verify labels: 
    kubectl get pods --show-labels

Step 10: Expose the Redis Database

kubectl expose pod database --port=6379 --name=redis-service --type=ClusterIP
  • Verify service: 
    kubectl get services

Step 11: Create a Web Deployment with Replicas

kubectl create deployment web-deployment --image=nginx --replicas=3
  • Check status: 
    kubectl get deployments

Step 12: Create a New Namespace and Deploy an App

kubectl create namespace my-test
kubectl create deployment redis-deploy -n my-test --image=redis --replicas=2
  • Verify deployment: 
    kubectl get pods -n my-test

Troubleshooting Cluster Issues

Your team reports an issue with the cluster:

[root@Test_Cluster1 ~]# kubectl get nodes
NAME            STATUS      ROLES                AGE     VERSION
Test_Cluster1   Ready       control-plane,master 17h     v1.30.6+k3s1
Test_Cluster2   NotReady    worker               33m     v1.29.6+k3s1
Test_Cluster3   Ready       worker               17h     v1.28.6+k3s1

Step 13: Investigate Node Health

kubectl describe node Test_Cluster2
kubectl get pods -A
  • What errors do you notice?
  • Is there a resource constraint or version mismatch?

Step 14: Restart K3s and Check Logs

systemctl restart k3s
journalctl -xeu k3s
  • What errors appear in the logs?
  • Does restarting resolve the issue?

Reflection and Additional Challenges

  1. Deploy your own container:

    • Build a custom Docker container and deploy it in the cluster.
    • Ensure it’s secure and scalable.

  2. Read about securing Kubernetes deployments:

  3. Secure Kubernetes in Practice:

Conclusion

At the end of this lab, you should:

✅ Have a fully operational K3s Kubernetes cluster.
✅ Be able to deploy and expose containerized applications.
✅ Know how to troubleshoot common Kubernetes errors.
✅ Understand security best practices for Kubernetes deployments.

📌 Next Steps: Continue testing deployments, set up monitoring tools like Prometheus or Grafana, and explore Ingress Controllers to manage external access.

Be sure to reboot the lab machine from the command line when you are done.