Kubernetes (K8s) Manifest Files and Commands

K8s Manifest Files

This project includes the following Kubernetes manifest files:

• mongo-config.yaml - This file defines a ConfigMap for MongoDB, which provides configuration settings for the database. The mongo-url key in the ConfigMap stores the MongoDB service name (mongo-service), allowing other components in the cluster to reference it easily.
• mongo-secret.yaml - This file defines a Secret that stores sensitive credentials for MongoDB, including mongo-user and mongo-password. These credentials are base64 encoded and referenced by the MongoDB and web application deployments for secure authentication.
• mongo.yaml - This file contains the deployment and service configuration for MongoDB:
  • Deployment: Creates a MongoDB pod using the mongo:5.0 image and sets environment variables from the Secret.
  • Service: Exposes MongoDB within the cluster using a service named mongo-service.
• webapp.yaml - This file contains the deployment and service configuration for the web application:
  • Deployment: Creates a web application pod using the nanajanashia/k8s-demo-app:v1.0 image and connects to MongoDB using credentials from the Secret and configuration from the ConfigMap.
  • Service: Exposes the web application using a NodePort service (webapp-service), making it accessible on port 30100.

Configuration Details

Deployment

selector:
  matchLabels:
    app: mongo

• Ensures the Deployment manages only the Pods with the label app: mongo.

Service

selector:
  app: mongo

• Ensures the Service routes traffic only to the Pods labeled app: mongo.

Deployment Process

To deploy the MongoDB and web application components, use the following commands:

1. Apply the MongoDB configuration:

   kubectl apply -f mongo-config.yaml

   Creates a ConfigMap named mongo-config.

2. Apply the MongoDB secrets:

   kubectl apply -f mongo-secret.yaml

   Creates a Secret named mongo-secret.

3. Deploy MongoDB:

   kubectl apply -f mongo.yaml

   Creates MongoDB deployment and service (mongo-deployment and mongo-service).

4. Deploy the web application:

   kubectl apply -f webapp.yaml

   Creates web application deployment and service (webapp-deployment and webapp-service).

K8s Commands

Start Minikube and Check Status

minikube start --vm-driver=hyperkit 
minikube status

Get Minikube Node's IP Address

minikube ip

Get Basic Info About K8s Components

kubectl get node
kubectl get pod
kubectl get svc
kubectl get all

Get Extended Info About Components

kubectl get pod -o wide
kubectl get node -o wide

Get Detailed Info About a Specific Component

kubectl describe svc {svc-name}
kubectl describe pod {pod-name}

Get Application Logs

kubectl logs {pod-name}

Stop Your Minikube Cluster

minikube stop

Usage Instructions

1. Start Minikube and ensure it's running properly.
2. Deploy the MongoDB and web application manifests using kubectl apply -f {filename}.
3. Verify the deployments and services using the commands provided above.
4. Check logs and debug if necessary.
5. Stop Minikube when finished.

Reference

This project is inspired by the Kubernetes deployment guide from Kubernetes in 1 Hour.

License

This project is open-source and available under the MIT License.