Exploring Kubernetes Networking

Introduction

Kubernetes networking is a deep and varied subject. In this lab, you will test your knowledge of Kubernetes networking by implementing a networking solution. You will also verify two pods can communicate with one another via your virtual container network.

Solution

Log in to the lab server using the credentials provided:

ssh cloud_user@<PUBLIC_IP_ADDRESS>

Fix the Issue Causing Pods Not to Start Up

1. List the pods to check their status:

   kubectl get pods
   

2. Check the node status:

   kubectl get nodes
   

   It looks like the nodes are NotReady.

3. Describe a node to see if you can get more info:

   kubectl describe node k8s-worker1
   

   It looks like kube-proxy, a component that handles networking-related tasks, is stuck starting up.

4. Check the status of the networking plugin pods:

   kubectl get pods -n kube-system
   

   The networking pods seem to be missing. Most likely, a networking plugin was never installed.

5. Install the Calico networking plugin:

   kubectl apply -f https://docs.projectcalico.org/v3.14/manifests/calico.yaml
   

6. Check the status of the Nodes and Pods again:

   kubectl get nodes
   

   They should both be Ready after about a minute.

   kubectl get pods
   

Verify You Can Communicate between Pods Using the Cluster Network

1. Verify the two pods can communicate over the network:

   kubectl get pods -o wide
   

2. Run curl on the IP address of the cyberdyne-frontend Pod (which will be listed in the output from the previous command):

   kubectl exec testclient -- curl <cyberdyne-frontend_POD_IP>
   

   The result should be HTML of an Nginx page, meaning the Pods are able to communicate.