1、 Eureka作为spring cloud的服务发现与注册中心，在整个的微服务体系中，处于核心位置。
单机模式下的eureka服务，显然不能满足高可用的实际生产环境，这就要求配置一个能够应对各种突发情况，具有较强容灾能力的eureka服务。Eureka通过“伙伴机制”实现高可用。每一台Eureka都需要在配置中指定另外两个Eureka的地址伙伴，Eureka启动时会向自己的伙伴节点获取当前已经存在的注册表，这样在向Eureka集群中新加机器时就不需要担心注册表的不完整。
2、 新建三个maven项目，分别为sc-eureka-cluster-server-node1，sc-eureka-cluster-server-node2，sc-eureka-cluster-server-node3。
项目结构如下：
备注：pom.xml和EurekaServerApplication.java的内容给单机模式是一模一样的，请参考上篇文章。
3、主要看下bootstap.yml或者application.yml文件的改动
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、分别启动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
如果出现上面圈住的日志说明启动成功
6、在浏览器分别访问
http://sc-eureka-cluster-server-node1:5001/
http://sc-eureka-cluster-server-node2:5002/
http://sc-eureka-cluster-server-node3:5002/
下面列出几个重要的配置项类：
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
