What is the purpose of the Deployment YAML file in the application deployment process?

The Deployment YAML file in Kubernetes describes the configuration for deploying an application. It specifies:

• The number of replicas (pods) of the application.
• The containers to be run, with their images and parameters.
• Update and recovery policies.
• Resources needed by the application (CPU, memory).

This file allows declarative management of the application's state in the cluster, ensuring automatic creation, scaling, and updating of pods.

Example of a simple Deployment YAML:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp-container
        image: myapp-image:latest
        ports:
        - containerPort: 8080