Eureka 高可用部署

一、高可用架构

1.1 单点问题

单节点 Eureka Server 存在单点故障风险：

1.2 集群架构

二、集群搭建

2.1 环境准备

节点	主机名	IP	端口
Eureka 1	eureka1	192.168.1.101	8761
Eureka 2	eureka2	192.168.1.102	8762
Eureka 3	eureka3	192.168.1.103	8763

2.2 配置 hosts

# /etc/hosts
192.168.1.101 eureka1
192.168.1.102 eureka2
192.168.1.103 eureka3

2.3 Eureka Server 1 配置

# application-eureka1.yml
server:
  port: 8761

spring:
  application:
    name: eureka-server

eureka:
  instance:
    hostname: eureka1
    prefer-ip-address: false
  client:
    register-with-eureka: true
    fetch-registry: true
    service-url:
      defaultZone: http://eureka2:8762/eureka/,http://eureka3:8763/eureka/
  server:
    enable-self-preservation: true
    eviction-interval-timer-in-ms: 60000

2.4 Eureka Server 2 配置

# application-eureka2.yml
server:
  port: 8762

spring:
  application:
    name: eureka-server

eureka:
  instance:
    hostname: eureka2
  client:
    register-with-eureka: true
    fetch-registry: true
    service-url:
      defaultZone: http://eureka1:8761/eureka/,http://eureka3:8763/eureka/

2.5 Eureka Server 3 配置

# application-eureka3.yml
server:
  port: 8763

spring:
  application:
    name: eureka-server

eureka:
  instance:
    hostname: eureka3
  client:
    register-with-eureka: true
    fetch-registry: true
    service-url:
      defaultZone: http://eureka1:8761/eureka/,http://eureka2:8762/eureka/

2.6 启动集群

# 节点1
java -jar eureka-server.jar --spring.profiles.active=eureka1

# 节点2
java -jar eureka-server.jar --spring.profiles.active=eureka2

# 节点3
java -jar eureka-server.jar --spring.profiles.active=eureka3

三、客户端配置

3.1 注册到集群

eureka:
  client:
    service-url:
      # 配置所有 Eureka Server 地址
      defaultZone: http://eureka1:8761/eureka/,http://eureka2:8762/eureka/,http://eureka3:8763/eureka/
  instance:
    prefer-ip-address: true

3.2 客户端行为

• 客户端会向所有配置的 Server 注册
• 只从第一个可用的 Server 获取注册表
• 某个 Server 不可用时自动切换

四、Docker 部署

4.1 Dockerfile

FROM openjdk:8-jdk-alpine

VOLUME /tmp

ARG JAR_FILE=target/*.jar
COPY ${JAR_FILE} app.jar

ENTRYPOINT ["java", "-jar", "/app.jar"]

4.2 docker-compose.yml

version: '3'

services:
  eureka1:
    build: .
    container_name: eureka1
    hostname: eureka1
    ports:
      - "8761:8761"
    environment:
      - SPRING_PROFILES_ACTIVE=eureka1
    networks:
      - eureka-net

  eureka2:
    build: .
    container_name: eureka2
    hostname: eureka2
    ports:
      - "8762:8762"
    environment:
      - SPRING_PROFILES_ACTIVE=eureka2
    networks:
      - eureka-net

  eureka3:
    build: .
    container_name: eureka3
    hostname: eureka3
    ports:
      - "8763:8763"
    environment:
      - SPRING_PROFILES_ACTIVE=eureka3
    networks:
      - eureka-net

networks:
  eureka-net:
    driver: bridge

4.3 启动

docker-compose up -d

五、Kubernetes 部署

5.1 ConfigMap

apiVersion: v1
kind: ConfigMap
metadata:
  name: eureka-config
data:
  application.yml: |
    spring:
      application:
        name: eureka-server
    eureka:
      client:
        register-with-eureka: true
        fetch-registry: true
      server:
        enable-self-preservation: true

5.2 StatefulSet

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: eureka
spec:
  serviceName: eureka
  replicas: 3
  selector:
    matchLabels:
      app: eureka
  template:
    metadata:
      labels:
        app: eureka
    spec:
      containers:
        - name: eureka
          image: eureka-server:latest
          ports:
            - containerPort: 8761
          env:
            - name: EUREKA_INSTANCE_HOSTNAME
              valueFrom:
                fieldRef:
                  fieldPath: metadata.name
            - name: EUREKA_CLIENT_SERVICEURL_DEFAULTZONE
              value: "http://eureka-0.eureka:8761/eureka/,http://eureka-1.eureka:8761/eureka/,http://eureka-2.eureka:8761/eureka/"
          volumeMounts:
            - name: config
              mountPath: /config
      volumes:
        - name: config
          configMap:
            name: eureka-config

5.3 Headless Service

apiVersion: v1
kind: Service
metadata:
  name: eureka
spec:
  clusterIP: None
  selector:
    app: eureka
  ports:
    - port: 8761
      targetPort: 8761

六、负载均衡配置

6.1 Nginx 负载均衡

upstream eureka_cluster {
    server eureka1:8761;
    server eureka2:8762;
    server eureka3:8763;
}

server {
    listen 80;
    server_name eureka.example.com;

    location / {
        proxy_pass http://eureka_cluster;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
    }
}

6.2 客户端配置

eureka:
  client:
    service-url:
      defaultZone: http://eureka.example.com/eureka/

七、监控与告警

7.1 健康检查端点

management:
  endpoints:
    web:
      exposure:
        include: health,info,metrics,prometheus
  endpoint:
    health:
      show-details: always

7.2 Prometheus 监控

# prometheus.yml
scrape_configs:
  - job_name: 'eureka'
    metrics_path: '/actuator/prometheus'
    static_configs:
      - targets:
          - 'eureka1:8761'
          - 'eureka2:8762'
          - 'eureka3:8763'

7.3 告警规则

# alert.rules
groups:
  - name: eureka
    rules:
      - alert: EurekaServerDown
        expr: up{job="eureka"} == 0
        for: 1m
        labels:
          severity: critical
        annotations:
          summary: "Eureka Server {{ $labels.instance }} is down"

八、故障转移测试

8.1 测试场景

8.2 测试步骤

1. 启动三节点集群
2. 注册服务到集群
3. 停止其中一个节点
4. 验证服务仍可正常注册和发现
5. 恢复节点，验证数据同步

九、最佳实践

9.1 部署建议

环境	节点数	说明
开发	1	单节点即可
测试	2	基本高可用
生产	3+	推荐奇数个节点

9.2 配置建议

eureka:
  server:
    # 开启自我保护
    enable-self-preservation: true
    # 续约阈值
    renewal-percent-threshold: 0.85
    # 剔除间隔
    eviction-interval-timer-in-ms: 60000
    
  instance:
    # 使用 IP 注册
    prefer-ip-address: true
    # 心跳间隔
    lease-renewal-interval-in-seconds: 30
    # 过期时间
    lease-expiration-duration-in-seconds: 90

十、总结

高可用要点：

1. 至少 3 个节点：保证容错能力
2. 互相注册：节点间数据同步
3. 客户端多地址：自动故障转移
4. 监控告警：及时发现问题