Docker and Kubernetes Deployment Strategies

# Multi-stage build for smaller images
FROM node:20-alpine AS builder

WORKDIR /app

# Copy package files
COPY package*.json ./

# Install dependencies
RUN npm ci --only=production

# Copy source code
COPY . .

# Build application
RUN npm run build

# Production stage
FROM node:20-alpine

WORKDIR /app

# Copy from builder
COPY --from=builder /app/node_modules ./node_modules
COPY --from=builder /app/dist ./dist
COPY --from=builder /app/package.json ./

# Create non-root user
RUN addgroup -g 1001 -S nodejs && \
    adduser -S nodejs -u 1001

USER nodejs

EXPOSE 3000

CMD ["node", "dist/index.js"]

version: '3.8'

services:
  app:
    build:
      context: .
      dockerfile: Dockerfile
      target: development
    ports:
      - "3000:3000"
    volumes:
      - .:/app
      - /app/node_modules
    environment:
      - NODE_ENV=development
      - DATABASE_URL=postgres://postgres:password@db:5432/myapp
    depends_on:
      - db
      - redis

  db:
    image: postgres:16-alpine
    volumes:
      - postgres_data:/var/lib/postgresql/data
    environment:
      - POSTGRES_USER=postgres
      - POSTGRES_PASSWORD=password
      - POSTGRES_DB=myapp
    ports:
      - "5432:5432"

  redis:
    image: redis:7-alpine
    ports:
      - "6379:6379"

volumes:
  postgres_data:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
  labels:
    app: myapp
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp
        image: myapp:latest
        ports:
        - containerPort: 3000
        env:
        - name: NODE_ENV
          value: "production"
        - name: DATABASE_URL
          valueFrom:
            secretKeyRef:
              name: myapp-secrets
              key: database-url
        resources:
          requests:
            memory: "256Mi"
            cpu: "250m"
          limits:
            memory: "512Mi"
            cpu: "500m"
        livenessProbe:
          httpGet:
            path: /health
            port: 3000
          initialDelaySeconds: 30
          periodSeconds: 10
        readinessProbe:
          httpGet:
            path: /ready
            port: 3000
          initialDelaySeconds: 5
          periodSeconds: 5

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

---
apiVersion: v1
kind: Service
metadata:
  name: myapp-internal
spec:
  selector:
    app: myapp
  ports:
  - protocol: TCP
    port: 3000
    targetPort: 3000
  type: ClusterIP

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  replicas: 10
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 2        # Can create 2 extra pods
      maxUnavailable: 0  # No pods should be down
  template:
    # ... pod template

# Blue deployment (current version)
apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-blue
spec:
  replicas: 5
  selector:
    matchLabels:
      app: myapp
      version: blue
  template:
    metadata:
      labels:
        app: myapp
        version: blue
    spec:
      containers:
      - name: myapp
        image: myapp:v1.0.0

---
# Green deployment (new version)
apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-green
spec:
  replicas: 5
  selector:
    matchLabels:
      app: myapp
      version: green
  template:
    metadata:
      labels:
        app: myapp
        version: green
    spec:
      containers:
      - name: myapp
        image: myapp:v2.0.0

---
# Service that switches between blue and green
apiVersion: v1
kind: Service
metadata:
  name: myapp
spec:
  selector:
    app: myapp
    version: blue  # Switch to 'green' to deploy new version
  ports:
  - port: 80
    targetPort: 3000

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-stable
spec:
  replicas: 9
  selector:
    matchLabels:
      app: myapp
      track: stable
  template:
    metadata:
      labels:
        app: myapp
        track: stable
    spec:
      containers:
      - name: myapp
        image: myapp:v1.0.0

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-canary
spec:
  replicas: 1  # 10% of traffic
  selector:
    matchLabels:
      app: myapp
      track: canary
  template:
    metadata:
      labels:
        app: myapp
        track: canary
    spec:
      containers:
      - name: myapp
        image: myapp:v2.0.0

---
apiVersion: v1
kind: Service
metadata:
  name: myapp
spec:
  selector:
    app: myapp
  ports:
  - port: 80
    targetPort: 3000

apiVersion: v1
kind: ConfigMap
metadata:
  name: myapp-config
data:
  NODE_ENV: "production"
  PORT: "3000"
  LOG_LEVEL: "info"
  config.yaml: |
    server:
      port: 3000
    database:
      host: postgres
      port: 5432

---
apiVersion: v1
kind: Secret
metadata:
  name: myapp-secrets
type: Opaque
stringData:
  database-url: "postgres://user:pass@postgres:5432/myapp"
  api-key: "your-api-key"
  jwt-secret: "your-jwt-secret"

# Chart.yaml
apiVersion: v2
name: myapp
description: My Application
version: 1.0.0
appVersion: "1.0.0"

# values.yaml
replicaCount: 3

image:
  repository: myapp
  pullPolicy: IfNotPresent
  tag: "1.0.0"

service:
  type: ClusterIP
  port: 80

resources:
  limits:
    cpu: 500m
    memory: 512Mi
  requests:
    cpu: 250m
    memory: 256Mi

autoscaling:
  enabled: false
  minReplicas: 3
  maxReplicas: 10
  targetCPUUtilizationPercentage: 80

apiVersion: v1
kind: ConfigMap
metadata:
  name: prometheus-config
data:
  prometheus.yml: |
    global:
      scrape_interval: 15s
    scrape_configs:
    - job_name: 'kubernetes-pods'
      kubernetes_sd_configs:
      - role: pod
      relabel_configs:
      - source_labels: [__meta_kubernetes_pod_annotation_prometheus_io_scrape]
        action: keep
        regex: true