Module 10 - Container Orchestration with Kubernetes

This repository contains a demo project created as part of my DevOps studies in the TechWorld with Nana – DevOps Bootcamp.

https://www.techworld-with-nana.com/devops-bootcamp

Demo Project: Install a stateful service (MongoDB) on Kubernetes using Helm

Technologies used: K8s, Helm, MongoDB, Mongo Express, DigitalOcean Kubernetes, Linux

Project Description:

• Create a managed K8s cluster with DigitalOcean Kubernetes
• Deploy replicated MongoDB service in DOKS cluster using a Helm chart
• Configure data persistence for MongoDB with DigitalOcean block storage
• Deploy UI client Mongo Express for MongoDB
• Deploy and configure nginx ingress to access the UI application from browser

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1. Create a Kubernetes Cluster on DigitalOcean

Provision a managed Kubernetes cluster through the DigitalOcean dashboard:

2. Connect to the Cluster

Download the kubeconfig file from DigitalOcean, then configure access:

chmod 400 k8s-id-kubeconfig.yaml
export KUBECONFIG=k8s-id-kubeconfig.yaml

Verify the connection:

kubectl cluster-info
kubectl get nodes

3. Install Helm

Install the Helm package manager by following the official installation guide.

4. Add the Bitnami Helm Repository

helm repo add bitnami https://charts.bitnami.com/bitnami

5. Configure MongoDB

Search for the available MongoDB chart versions:

helm search repo bitnami/mongodb

For detailed chart parameters, see the Bitnami MongoDB chart documentation.

Check the available storage classes in your cluster:

kubectl get storageclass

Set the appropriate storage class in helm-mongodb.yaml:

persistence:
  storageClass: "do-block-storage"

6. Deploy MongoDB

helm install mongodb --values helm-mongodb.yaml bitnami/mongodb

A PersistentVolumeClaim (PVC) is automatically created for each of the 3 replica pods:

7. Deploy Mongo Express (MongoDB UI Client)

Retrieve the MongoDB secret configuration:

kubectl get secret mongodb -o yaml

The Mongo Express deployment uses the following environment variables to connect to MongoDB (see helm-mongo-express.yaml):

env:
  - name: ME_CONFIG_MONGODB_ADMINUSERNAME
    value: root
  - name: ME_CONFIG_MONGODB_ADMINPASSWORD
    valueFrom:
      secretKeyRef:
        name: mongodb
        key: mongodb-root-password
  - name: ME_CONFIG_MONGODB_URL
    value: "mongodb://$(ME_CONFIG_MONGODB_ADMINUSERNAME):$(ME_CONFIG_MONGODB_ADMINPASSWORD)@mongodb-0.mongodb-headless:27017"

Note: mongodb-0.mongodb-headless refers to the first pod in the StatefulSet, resolved via the headless service (verify with kubectl get svc).

Apply the deployment:

kubectl apply -f helm-mongo-express.yaml

Verify the pod is running:

kubectl get pod

8. Deploy and Configure Nginx Ingress Controller

Add the ingress-nginx Helm repository:

helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx

Install the Nginx Ingress Controller:

helm install nginx-ingress ingress-nginx/ingress-nginx --set controller.publishService.enabled=true

Verify the controller is running:

kubectl get pods
kubectl logs nginx-ingress-ingress-nginx-controller-<pod-id>

A DigitalOcean Load Balancer is automatically provisioned:

Note the external IP address assigned to the ingress service:

kubectl get svc

9. Create and Apply the Ingress Rule

Update the host in helm-ingress.yaml with your external IP (replacing dots with dashes):

- host: <your-ip-address>.nip.io
  # Replace <your-ip-address> with your actual external IP

Apply the ingress rule:

kubectl apply -f helm-ingress.yaml

10. Access the Application

Navigate to http://<your-ip-address>.nip.io in your browser.

Default credentials:

Field	Value
User	admin
Password	pass