YouTip

Introduction

Pods are the atomic units of Kubernetes, and Deployments manage their lifecycle. Understanding these resources is fundamental to running applications on Kubernetes.

Pod Definition

# pod.yaml
apiVersion: v1
kind: Pod
metadata:
  name: myapp-pod
  labels:
    app: myapp
spec:
  containers:
  - name: myapp
    image: nginx:1.25
    ports:
    - containerPort: 80
    resources:
      requests:
        memory: "64Mi"
        cpu: "250m"
      limits:
        memory: "128Mi"
        cpu: "500m"

Deployment

# 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
        image: nginx:1.25
        ports:
        - containerPort: 80

Managing Deployments

# Apply configuration
kubectl apply -f deployment.yaml

# Check status
kubectl get deployments
kubectl get pods

# View detailed info
kubectl describe deployment myapp-deployment

# Update image
kubectl set image deployment/myapp-deployment myapp=nginx:1.26

# Rollback
kubectl rollout undo deployment/myapp-deployment

Summary

Deployments manage pods declaratively. Define desired state in YAML, apply with kubectl, and use rollout commands for updates and rollbacks.