Container Orchestration với Kubernetes

Giới thiệu Kubernetes

Kubernetes là hệ thống container orchestration mã nguồn mở để tự động hóa deployment, scaling, và quản lý ứng dụng containerized.

Kubernetes Concepts

Pods

apiVersion: v1
kind: Pod
metadata:
  name: my-app-pod
  labels:
    app: my-app
    tier: frontend
spec:
  containers:
  - name: my-app
    image: my-app:1.0
    ports:
    - containerPort: 3000
    env:
    - name: NODE_ENV
      value: "production"
    resources:
      requests:
        memory: "64Mi"
        cpu: "250m"
      limits:
        memory: "128Mi"
        cpu: "500m"

Deployments

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-app
        image: my-app:1.0
        ports:
        - containerPort: 3000
        livenessProbe:
          httpGet:
            path: /health
            port: 3000
          initialDelaySeconds: 30
          periodSeconds: 10
        readinessProbe:
          httpGet:
            path: /ready
            port: 3000
          initialDelaySeconds: 5
          periodSeconds: 5

Services

apiVersion: v1
kind: Service
metadata:
  name: my-app-service
spec:
  selector:
    app: my-app
  ports:
  - protocol: TCP
    port: 80
    targetPort: 3000
  type: LoadBalancer

Kubernetes Commands

Basic Commands

# Get cluster information
kubectl cluster-info

# Get nodes
kubectl get nodes

# Get pods
kubectl get pods

# Get services
kubectl get services

# Get deployments
kubectl get deployments

Application Management

# Apply configuration
kubectl apply -f deployment.yaml

# Scale deployment
kubectl scale deployment my-app-deployment --replicas=5

# View logs
kubectl logs -f deployment/my-app-deployment

# Port forwarding
kubectl port-forward service/my-app-service 8080:80

Advanced Kubernetes Features

ConfigMaps và Secrets

# ConfigMap
apiVersion: v1
kind: ConfigMap
metadata:
  name: app-config
data:
  database.url: "postgresql://localhost:5432/mydb"
  cache.host: "redis://localhost:6379"
  app.port: "3000"

# Secret
apiVersion: v1
kind: Secret
metadata:
  name: app-secrets
type: Opaque
data:
  database.password: cGFzc3dvcmQxMjM=  # base64 encoded
  api.key: YXBpLWtleS1zZWNyZXQ=

Persistent Volumes

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: postgres-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi

Kubernetes trong Production

Resource Management

resources:
  requests:
    memory: "128Mi"
    cpu: "250m"
  limits:
    memory: "256Mi"
    cpu: "500m"

Health Checks

livenessProbe:
  httpGet:
    path: /health
    port: 3000
  initialDelaySeconds: 30
  periodSeconds: 10
  failureThreshold: 3

readinessProbe:
  httpGet:
    path: /ready
    port: 3000
  initialDelaySeconds: 5
  periodSeconds: 5
  successThreshold: 1
  failureThreshold: 3

Horizontal Pod Autoscaling

apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: my-app-hpa
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: my-app-deployment
  minReplicas: 2
  maxReplicas: 10
  metrics:
  - type: Resource
    resource:
      name: cpu
      target:
        type: Utilization
        averageUtilization: 50