2、eureka注冊中心集群

公眾號： java樂園

1、 Eureka作為spring cloud的服務發現與注冊中心，在整個的微服務體系中，處于核心位置。單機模式下的eureka服務，顯然不能滿足高可用的實際生產環境，這就要求配置一個能夠應對各種突發情況，具有較強容災能力的eureka服務。Eureka通過“伙伴機制”實現高可用。每一臺Eureka都需要在配置中指定另外兩個Eureka的地址伙伴，Eureka啟動時會向自己的伙伴節點獲取當前已經存在的注冊表，這樣在向Eureka集群中新加機器時就不需要擔心注冊表的不完整。
2、 新建三個maven項目，分別為sc-eureka-cluster-server-node1，sc-eureka-cluster-server-node2，sc-eureka-cluster-server-node3。項目結構如下：

備注：pom.xml和EurekaServerApplication.java的內容給單機模式是一模一樣的，請參考上篇文章。
3、 主要看下bootstap.yml或者application.yml文件的改動
sc-eureka-cluster-server-node1

spring:
    application:
        name: sc-eureka-cluster-server-node1

server:
    port: 5001

eureka:
    instance:
        hostname: sc-eureka-cluster-server-node1
        lease-renewal-interval-in-seconds: 30
        lease-expiration-duration-in-seconds: 30
        prefer-ip-address: true
    client:
        registerWithEureka: false
        fetchRegistry: false
        serviceUrl:
            defaultZone: http://sc-eureka-cluster-server-node2:5002/eureka/,http://sc-eureka-cluster-server-node3:5003/eureka/

sc-eureka-cluster-server-node2

spring:
    application:
        name: sc-eureka-cluster-server-node2

server:
    port: 5002

eureka:
    instance:
        hostname: sc-eureka-cluster-server-node2
        lease-renewal-interval-in-seconds: 30
        lease-expiration-duration-in-seconds: 30
        prefer-ip-address: true
    client:
        registerWithEureka: false
        fetchRegistry: false
        serviceUrl:
            defaultZone: http://sc-eureka-cluster-server-node1:5001/eureka/,http://sc-eureka-cluster-server-node3:5003/eureka/

sc-eureka-cluster-server-node3

spring:
    application:
        name: sc-eureka-cluster-server-node3

server:
    port: 5003

eureka:
    instance:
        hostname: sc-eureka-cluster-server-node3
        lease-renewal-interval-in-seconds: 30
        lease-expiration-duration-in-seconds: 30
        prefer-ip-address: true
    client:
        registerWithEureka: false
        fetchRegistry: false
        serviceUrl:
            defaultZone: http://sc-eureka-cluster-server-node1:5001/eureka/,http://sc-eureka-cluster-server-node2:5001/eureka/

4、 配置host文件C:\Windows\System32\drivers\etc\hosts
127.0.0.1 sc-eureka-cluster-server-node1
127.0.0.1 sc-eureka-cluster-server-node2
127.0.0.1 sc-eureka-cluster-server-node3

5、 分別啟動EurekaServerApplication.java
sc-eureka-cluster-server-node1的日志：

sc-eureka-cluster-server-node2的日志：

sc-eureka-cluster-server-node3的日志

如果出現上面圈住的日志說明啟動成功

6、 在瀏覽器分別訪問
http://sc-eureka-cluster-server-node1:5001/

http://sc-eureka-cluster-server-node2:5002/

http://sc-eureka-cluster-server-node3:5002/

下面列出幾個重要的配置項類：

org.springframework.boot.autoconfigure.web.ServerProperties
org.springframework.cloud.netflix.eureka.EurekaInstanceConfigBean
com.netflix.eureka.EurekaServerConfig
com.netflix.eureka.DefaultEurekaServerConfig
org.springframework.cloud.netflix.eureka.server.EurekaServerConfigBean
com.netflix.discovery.EurekaClientConfig
com.netflix.discovery.DefaultEurekaClientConfig
org.springframework.cloud.netflix.eureka.EurekaClientConfigBean