Deployments

A Deployment is a higher-level abstraction that manages ReplicaSets and provides declarative updates to Pods. It allows you to define the desired state of your application and automatically manages the underlying ReplicaSets to achieve that state.

Example Deployment Definition

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-deployment
  labels:
    app: myapp
    type: front-end
spec:
  replicas: 3
  
  selector:
    matchLabels:
      type: front-end
  
  template:
    metadata:
      name: myapp-pod
      labels:
        app: myapp
        type: front-end
    spec:
      containers:
      - name: nginx-container
        image: nginx

In this example, we define a Deployment named myapp-deployment that maintains 3 replicas of a pod with the label app: myapp. The pod template specifies the container to run, which is an Nginx container. The Deployment will automatically create and manage the underlying ReplicaSets to ensure that the desired number of replicas is always running.

Commands

Create a Deployment from a definition file:

kubectl create -f myapp-deployment.yaml

Show the list of Deployments:

kubectl get deployments

Detailed information about a Deployment:

kubectl describe deployment myapp-deployment

Delete a Deployment:

kubectl delete deployment myapp-deployment