To deploy an application with two deployments in Kubernetes,

Category : Kubernetes | Sub Category : Kubernetes With Java | By Prasad Bonam Last updated: 2023-11-21 14:13:48 Viewed : 212

To deploy an application with two deployments in Kubernetes, you would typically define two separate YAML files, each describing a Deployment resource. Below is a simple example of deploying two nginx deployments as part of the same application. One deployment is labeled as "web-frontend" and the other as "web-backend".

1. Create YAML files for Deployments:

frontend-deployment.yaml:

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apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-frontend
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web
      tier: frontend
  template:
    metadata:
      labels:
        app: web
        tier: frontend
    spec:
      containers:
      - name: nginx
        image: nginx:latest
        ports:
        - containerPort: 80

backend-deployment.yaml:

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apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-backend
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web
      tier: backend
  template:
    metadata:
      labels:
        app: web
        tier: backend
    spec:
      containers:
      - name: nginx
        image: nginx:latest
        ports:
        - containerPort: 80

2. Apply Deployments to the Cluster:

Use kubectl apply to deploy the applications:

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kubectl apply -f frontend-deployment.yaml
kubectl apply -f backend-deployment.yaml

3. Verify Deployments:

Check the status of the deployments:

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kubectl get deployments

Check the status of the pods:

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kubectl get pods

4. Expose Services (Optional):

If your application requires external access, you can expose the services using Kubernetes Services. For example:

frontend-service.yaml:

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apiVersion: v1
kind: Service
metadata:
  name: web-frontend-service
spec:
  selector:
    app: web
    tier: frontend
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80
  type: LoadBalancer

backend-service.yaml:

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apiVersion: v1
kind: Service
metadata:
  name: web-backend-service
spec:
  selector:
    app: web
    tier: backend
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80
  type: LoadBalancer

Apply the service configurations:

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kubectl apply -f frontend-service.yaml
kubectl apply -f backend-service.yaml

5. Access the Application:

If you have exposed the services as LoadBalancer types, you can get the external IPs:

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kubectl get services

Access the frontend and backend services using their respective external IPs.

This example demonstrates a simple scenario where you have a frontend and backend deployment, each with its own set of replicas. Depending on your applications complexity, you might need to configure additional resources such as ConfigMaps, Secrets, or Persistent Volumes. Adjust the YAML files according to your applications requirements.