Minikube Multi-Container Pods: NGINX Layer 7 Load Balancing and Service Abstraction

Have you ever been curious whether Kubernetes can actually be run on personal computers? In this tutorial we will show you how to create a multi-container Pod in Minikube, set NGINX for complex Layer 7 load balancing and easily manage your services. Are you prepared to convert your own development atmosphere into Kubernetes’ strength? Let’s get started!

GitHub link

Here’s what we’ll cover:

• Creating a Multi-Container Pod in Minikube: We’ll set up a Pod with three containers: firewall-container, container-1, and container-2.
• Hiding Backend Services Behind a Firewall: We’ll route all traffic through firewall-container, so container-1 and container-2 stay hidden from direct access.
• Setting Up Layer 7 (L7) Load Balancing with NGINX: We’ll configure NGINX in the firewall-container to act as a reverse proxy and balance traffic between container-1 and container-2.

Required Tools:

1. Windows 10 PC
2. Minikube – Install Minikube by following the instructions on the official Minikube installation page.
3. Docker Desktop – Go to Docker’s website, download and install install Docker Desktop in order to manage containerized applications.

Make sure to follow the installation links and instructions for a smooth setup.

Make sure to follow the installation links and instructions for a smooth setup.

We’ll first bring up Minikube and deploy our pod:

Start Minikube by running:

minikube start

Once Minikube is up, navigate to the directory where your pod.yaml file is located, and apply the YAML configuration with:

kubectl apply -f .\pod.yaml

Our containers are up now. To allow for the proper routing between your local Windows environment and the Minikube cluster, a network tunnel must be created as follows:

minikube tunnel

To access easily the Kubernetes service from windows run:

minikube service firewall-service

This command will open your default browser, where you can see a response from the firewall-container.

To access container-1 service: http://127.0.0.1:8195/app1

To access container-2 service: http://127.0.0.1:8195/app2

With services already deployed, let’s break down commands step-by-step for verifying the pod and container services.

Here’s a step-by-step guide for running the commands to manage the pod and services and observe their various parameters:

 Step 1: Deploy the Pod

kubectl apply -f pod.yaml

This command applies the configuration file (pod.yaml) and creates the pod along with its containers.

Step 2: Verify Pod Status

kubectl get pods

This command shows the status of all running pods. You should see firewall-pod with 3/3 containers running.

 Step 3: Check the Service

kubectl get services

kubectl get svc firewall-service

This command lists all services, including the firewall-service, which should show the external NodePort (30007) and internal ClusterIP.

Step 4: Check the Pod Details

kubectl describe pod firewall-pod

This command provides detailed information about the pod, including container statuses, IP addresses, and event logs.

Step 5: Access Containers within the Pod

To access a specific container:

kubectl exec -it firewall-pod –container container-1 — /bin/sh

Or to access other containers:

kubectl exec -it firewall-pod –container container-2 — /bin/sh

kubectl exec -it firewall-pod –container firewall-container — /bin/sh

Step 6: Test Requests Between Containers

Once inside the firewall-container, test the connection to the other containers:

# Access container-1

curl 127.0.0.1:8081

# Access container-2

curl 127.0.0.1:8082

You should see responses from container-1 and container-2.

Step 7: Access Service Externally

To find the Minikube IP:

minikube ip

Now access the service using the Minikube IP and the NodePort (30007):

http://<Minikube-IP>:30007/app1

http://<Minikube-IP>:30007/app2

Step 8: Check Logs

To view the logs from a specific container:

kubectl logs firewall-pod -c firewall-container

kubectl logs firewall-pod -c container-1

kubectl logs firewall-pod -c container-2

Step 9: Clean Up Resources

To delete the pod:

kubectl delete pod firewall-pod

To delete the service:

kubectl delete svc firewall-service

Shortcut to Get Minikube Service URL

minikube service firewall-service –url

This command provides the URL for accessing the service directly.

Step 10: Reapply Configuration

If you want to redeploy the pod:

kubectl apply -f pod.yaml

This YAML outlines a multi-container pod that includes three different types of containers which are: container-1 and container-2 that run NGINX with their individual configurations; and then there is firewall-container which serves as an NGINX reverse proxy. To forward requests from the backend containers to each other based on the respective path, the firewall-container uses a ConfigMap. The service makes the pod accessible from outside by means of NodePort at port 8090 thus routing incoming requests through the firewall-container. Also, the ConfigMap establishes an NGINX balance for Layer 7 (L7) traffic among the two backend services.