Introduction to Kubernetes

Kubernetes in Plain English

Container orchestration without the buzzwords.

Core Concepts

Pod: One or more containers that run together Service: Stable network endpoint for pods Deployment: Manages pod replicas and updates Namespace: Logical separation of resources

Basic Deployment

# deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-app
        image: my-app:1.0.0
        ports:
        - containerPort: 80

Exposing Services

# service.yaml
apiVersion: v1
kind: Service
metadata:
  name: my-app
spec:
  selector:
    app: my-app
  ports:
  - port: 80
    targetPort: 80
  type: LoadBalancer

Common Commands

# Apply configuration
kubectl apply -f deployment.yaml

# Get resources
kubectl get pods
kubectl get services
kubectl get deployments

# Describe (debug)
kubectl describe pod my-app-xxx

# Logs
kubectl logs my-app-xxx
kubectl logs -f my-app-xxx  # Follow

# Shell into pod
kubectl exec -it my-app-xxx -- /bin/sh

Environment Variables

spec:
  containers:
  - name: my-app
    env:
    - name: DB_HOST
      value: "mysql-service"
    - name: DB_PASSWORD
      valueFrom:
        secretKeyRef:
          name: db-secrets
          key: password

Start Simple

1. Use managed K8s (EKS, GKE, AKS)
2. Start with Deployment + Service
3. Add complexity as needed
4. Use Helm for complex apps