Microservices Deployment¶

Overview¶

This guide covers various deployment strategies and patterns for microservices architecture, including containerization, orchestration, and continuous deployment practices.

Prerequisites¶

Basic understanding of microservices architecture
Knowledge of Docker and Kubernetes
Familiarity with CI/CD concepts
Understanding of cloud platforms

Learning Objectives¶

Understand different deployment strategies
Learn containerization best practices
Master Kubernetes deployments
Implement CI/CD pipelines
Handle configuration management

Containerization¶

Dockerfile Example¶

FROM openjdk:17-jdk-slim
WORKDIR /app
COPY target/*.jar app.jar
EXPOSE 8080
ENTRYPOINT ["java", "-jar", "app.jar"]

Docker Compose Configuration¶

version: '3.8'
services:
  user-service:
    build: ./user-service
    ports:
      - "8080:8080"
    environment:
      - SPRING_PROFILES_ACTIVE=prod
      - DB_HOST=postgres
    depends_on:
      - postgres

  postgres:
    image: postgres:13
    environment:
      - POSTGRES_USER=admin
      - POSTGRES_PASSWORD=secret
      - POSTGRES_DB=userdb

Kubernetes Deployment¶

Basic Deployment¶

apiVersion: apps/v1
kind: Deployment
metadata:
  name: user-service
spec:
  replicas: 3
  selector:
    matchLabels:
      app: user-service
  template:
    metadata:
      labels:
        app: user-service
    spec:
      containers:
      - name: user-service
        image: user-service:1.0.0
        ports:
        - containerPort: 8080
        env:
        - name: SPRING_PROFILES_ACTIVE
          value: "prod"
        readinessProbe:
          httpGet:
            path: /actuator/health
            port: 8080
          initialDelaySeconds: 30
          periodSeconds: 10

Service Configuration¶

apiVersion: v1
kind: Service
metadata:
  name: user-service
spec:
  selector:
    app: user-service
  ports:
  - port: 80
    targetPort: 8080
  type: LoadBalancer

ConfigMap and Secrets¶

apiVersion: v1
kind: ConfigMap
metadata:
  name: user-service-config
data:
  application.yaml: |
    spring:
      datasource:
        url: jdbc:postgresql://postgres:5432/userdb

---
apiVersion: v1
kind: Secret
metadata:
  name: user-service-secrets
type: Opaque
data:
  db-password: base64encodedpassword

CI/CD Pipeline¶

GitHub Actions Workflow¶

name: CI/CD Pipeline

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2

    - name: Set up JDK
      uses: actions/setup-java@v2
      with:
        java-version: '17'

    - name: Build with Maven
      run: mvn clean package

    - name: Build Docker image
      run: docker build -t user-service:${{ github.sha }} .

    - name: Push to Registry
      run: |
        docker tag user-service:${{ github.sha }} registry/user-service:${{ github.sha }}
        docker push registry/user-service:${{ github.sha }}

    - name: Deploy to Kubernetes
      run: |
        kubectl set image deployment/user-service \
          user-service=registry/user-service:${{ github.sha }}

Jenkins Pipeline¶

pipeline {
    agent any

    stages {
        stage('Build') {
            steps {
                sh 'mvn clean package'
            }
        }

        stage('Test') {
            steps {
                sh 'mvn test'
            }
        }

        stage('Build Docker Image') {
            steps {
                sh 'docker build -t user-service:${BUILD_NUMBER} .'
            }
        }

        stage('Deploy to Kubernetes') {
            steps {
                sh '''
                    kubectl apply -f k8s/
                    kubectl set image deployment/user-service \
                        user-service=user-service:${BUILD_NUMBER}
                '''
            }
        }
    }
}

Configuration Management¶

Spring Cloud Config¶

spring:
  cloud:
    config:
      server:
        git:
          uri: https://github.com/org/config-repo
          searchPaths: '{application}'

Kubernetes ConfigMap Mounting¶

apiVersion: apps/v1
kind: Deployment
metadata:
  name: user-service
spec:
  template:
    spec:
      containers:
      - name: user-service
        volumeMounts:
        - name: config-volume
          mountPath: /config
      volumes:
      - name: config-volume
        configMap:
          name: user-service-config

Deployment Strategies¶

Blue-Green Deployment¶

apiVersion: apps/v1
kind: Deployment
metadata:
  name: user-service-blue
spec:
  replicas: 3
  template:
    metadata:
      labels:
        app: user-service
        version: blue
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: user-service-green
spec:
  replicas: 3
  template:
    metadata:
      labels:
        app: user-service
        version: green

Canary Deployment¶

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: user-service
spec:
  hosts:
  - user-service
  http:
  - route:
    - destination:
        host: user-service
        subset: v1
      weight: 90
    - destination:
        host: user-service
        subset: v2
      weight: 10

Best Practices¶

Use immutable containers
Implement proper health checks
Use configuration management
Implement automated rollbacks
Monitor deployments
Use proper resource limits
Implement proper logging

Common Pitfalls¶

Missing health checks
Poor resource management
Inadequate monitoring
Missing rollback strategies
Configuration mismanagement
Insufficient testing

Implementation Examples¶

Complete Kubernetes Deployment¶

apiVersion: apps/v1
kind: Deployment
metadata:
  name: user-service
spec:
  replicas: 3
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
  template:
    spec:
      containers:
      - name: user-service
        image: user-service:1.0.0
        resources:
          requests:
            memory: "256Mi"
            cpu: "100m"
          limits:
            memory: "512Mi"
            cpu: "200m"
        livenessProbe:
          httpGet:
            path: /actuator/health/liveness
            port: 8080
        readinessProbe:
          httpGet:
            path: /actuator/health/readiness
            port: 8080
        env:
        - name: SPRING_PROFILES_ACTIVE
          value: "prod"
        - name: DB_PASSWORD
          valueFrom:
            secretKeyRef:
              name: user-service-secrets
              key: db-password

Helm Chart Structure¶

user-service/
├── Chart.yaml
├── values.yaml
├── templates/
│   ├── deployment.yaml
│   ├── service.yaml
│   ├── configmap.yaml
│   └── secrets.yaml
└── charts/

Resources for Further Learning¶

Practice Exercises¶

Create a complete Kubernetes deployment
Implement blue-green deployment
Set up a CI/CD pipeline
Configure monitoring for deployments
Implement automated rollbacks