You almost never create Pods directly. You create a Deployment, and the Deployment creates and manages Pods for you. A Deployment is the standard way to run applications in Kubernetes.

What a Deployment Does

You tell the Deployment: "I want 3 replicas of my-app running"

Deployment creates:
  Pod 1 (my-app)    running
  Pod 2 (my-app)    running
  Pod 3 (my-app)    running

Pod 2 crashes:
  Deployment notices: "I have 2, I need 3"
  Deployment creates Pod 4 automatically
  You never had to do anything

A Deployment manages a ReplicaSet, which manages the actual Pods. You work with Deployments — the ReplicaSet is mostly managed automatically.

Creating a Deployment

# deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
spec:
  replicas: 3                    # how many pods to run
  selector:
    matchLabels:
      app: my-app                # which pods this deployment manages
  template:                      # pod template — what each pod looks like
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-app
        image: nginx:1.25
        ports:
        - containerPort: 80
        resources:
          requests:
            memory: "64Mi"
            cpu: "250m"
          limits:
            memory: "128Mi"
            cpu: "500m"

kubectl apply -f deployment.yaml          # create or update deployment
kubectl get deployments                   # list deployments
kubectl get pods                          # see the 3 pods it created
kubectl describe deployment my-app       # detailed status

# Scale
kubectl scale deployment my-app --replicas=5   # scale to 5 pods
kubectl scale deployment my-app --replicas=1   # scale down to 1

# Update image (triggers rolling update)
kubectl set image deployment/my-app my-app=nginx:1.26

# Delete
kubectl delete deployment my-app

Rolling Updates

When you update a Deployment (new image, new config), Kubernetes does a rolling update by default — it replaces Pods one at a time so your application stays available throughout.

Rolling Update (replicas: 3):

Step 1: Create Pod 4 (new version)
  Pod 1 (v1) running
  Pod 2 (v1) running
  Pod 3 (v1) running
  Pod 4 (v2) starting...

Step 2: Pod 4 ready, delete Pod 1
  Pod 2 (v1) running
  Pod 3 (v1) running
  Pod 4 (v2) running
  Pod 5 (v2) starting...

Step 3: Pod 5 ready, delete Pod 2
  ...and so on until all pods are v2

Zero downtime throughout the process.

kubectl rollout status deployment/my-app    # watch the rollout progress
kubectl rollout history deployment/my-app   # see rollout history
kubectl rollout undo deployment/my-app      # rollback to previous version
kubectl rollout undo deployment/my-app --to-revision=2   # rollback to specific version