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: Deploy MongoDB and Mongo Express into local K8s cluster

Technologies used: Kubernetes, Docker, MongoDB, Mongo Express

Project Description:

• Setup local K8s cluster with Minikube
• Deploy MongoDB and MongoExpress with configuration and credentials extracted into ConfigMap and Secret

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Prerequisites

Install Minikube by following the official documentation.

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Deploy MongoDB and Mongo Express with ConfigMap and Secret

Architecture Overview

The setup consists of a MongoDB database and a Mongo Express web UI, with credentials stored in a Kubernetes Secret and the database URL stored in a ConfigMap.

1. Generate the MongoDB Deployment manifest

kubectl create deploy mongodb-deployment --image mongo --dry-run=client -o yaml > mongo.yaml

See: mongo.yaml

2. Create the Secret for database credentials

Base64-encode the credentials:

echo -n 'root-user' | base64
# cm9vdC11c2Vy

echo -n 'root-password' | base64
# cm9vdC1wYXNzd29yZA==

See: mongo-secret.yaml

Apply the secret:

kubectl apply -f mongo-secret.yaml

3. Reference the Secret in the MongoDB Deployment

Add the following environment variables to the container spec in mongo.yaml:

env:
  - name: MONGO_INITDB_ROOT_USERNAME
    valueFrom:
      secretKeyRef:
        name: mongodb-secret
        key: mongo-root-username
  - name: MONGO_INITDB_ROOT_PASSWORD
    valueFrom:
      secretKeyRef:
        name: mongodb-secret
        key: mongo-root-password

See: mongo.yaml

4. Deploy MongoDB

kubectl apply -f mongo.yaml

5. Add a ClusterIP Service for MongoDB

Append the following Service definition to mongo.yaml:

---
apiVersion: v1
kind: Service
metadata:
  name: mongodb-service
spec:
  selector:
    app: mongodb-deployment
  ports:
    - protocol: TCP
      port: 27017
      targetPort: 27017

See: mongo.yaml

Apply the updated manifest:

kubectl apply -f mongo.yaml

6. Create a ConfigMap for the database URL

kubectl create configmap mongodb-configmap \
  --from-literal=database_url="mongodb-service:27017" \
  --dry-run=client -o yaml > mongo-configmap.yaml

Apply the ConfigMap:

kubectl apply -f mongo-configmap.yaml

7. Create the Mongo Express Deployment

Generate the base manifest:

kubectl create deploy mongo-express --image mongo-express --dry-run=client -o yaml > mongo-express.yaml

Then add the following environment variables to the container spec:

env:
  - name: ME_CONFIG_MONGODB_ADMINUSERNAME
    valueFrom:
      secretKeyRef:
        name: mongodb-secret
        key: mongo-root-username
  - name: ME_CONFIG_MONGODB_ADMINPASSWORD
    valueFrom:
      secretKeyRef:
        name: mongodb-secret
        key: mongo-root-password
  - name: DATABASE_URL
    valueFrom:
      configMapKeyRef:
        name: mongodb-configmap
        key: database_url
  - name: ME_CONFIG_MONGODB_URL
    value: "mongodb://$(ME_CONFIG_MONGODB_ADMINUSERNAME):$(ME_CONFIG_MONGODB_ADMINPASSWORD)@$(DATABASE_URL)"

See: mongo-express.yaml

Deploy Mongo Express:

kubectl apply -f mongo-express.yaml

8. Add a LoadBalancer Service for Mongo Express

Append the following Service definition to mongo-express.yaml:

---
apiVersion: v1
kind: Service
metadata:
  name: mongo-express-service
spec:
  selector:
    app: mongo-express
  type: LoadBalancer
  ports:
    - protocol: TCP
      port: 8081
      targetPort: 8081
      nodePort: 30000

See: mongo-express.yaml

Apply the updated manifest:

kubectl apply -f mongo-express.yaml

9. Access Mongo Express in the browser

Expose the service via Minikube:

minikube service mongo-express-service

Sign in with the default Mongo Express credentials:

Field	Value
Username	admin
Password	pass

Demo