Kubernetes deployments

the deployment provides us with the capability to upgrade the underlying instances seamlessly using a rolling update, undo changes, pause and resume changes as required.

The content of a deployment definition file is exactly similar to the Kubernetes - replication controller and replicaSets definition file except for the kind which is now going to be Deployment

the deployment automatically creates a replicaSet which create pods

 
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80