翻看了不少网上的教程   千篇一律  经过个人实践 总结了几个要点：

#  eureka server 高可用 配置  要点  eureka.instance.prefer-ip-address 不建议设置为true #  eureka.client.registerWithEureka、 eureka.client.fetchRegistry 都要设置为true   默认值都为true #  eureka.instance.appname  =spring.application.name #  重要  defaultZone  高可用 不要使用ip 应该使用相应的域名DNS来配置   也就是 eureka.instance.hostname  指定DNS

样例配置   采用 3个实例集群  8761->8762->8763->8761     application.yml 如下：

运行指定配置文件  例如在springboot 可执行jar 执行 

java -jar discovery-server-1.0-SNAPSHOT.jar --spring.profiles.active=master

--- server:   port: 8761 spring:   profiles: master   application:     name: DISCOVERY-SERVER eureka:   environment: prod   instance:   # 此处配置域名     hostname: peer1     appname: DISCOVERY-SERVER   client:     healthcheck:       enabled: true #   向服务注册中心注册     registerWithEureka: true #    检索服务     fetchRegistry: true     serviceUrl:       defaultZone: http://${eureka.instance.hostname}:8762/eureka/   server:     enable-self-preservation: true --- server:   port: 8762 spring:   profiles: cluster1   application:     name: DISCOVERY-SERVER eureka:   environment: prod   instance:   # 此处配置域名     hostname: peer2     appname: DISCOVERY-SERVER   client:     healthcheck:       enabled: true #   向服务注册中心注册     registerWithEureka: true #    检索服务     fetchRegistry: true     serviceUrl:       defaultZone: http://${eureka.instance.hostname}:8763/eureka/   server:     enable-self-preservation: true --- server:   port: 8763 spring:   profiles: cluster2   application:     name: DISCOVERY-SERVER eureka:   environment: prod   instance: # 此处配置域名     hostname: peer1     appname: DISCOVERY-SERVER   client:     healthcheck:       enabled: true #   向服务注册中心注册     registerWithEureka: true #    检索服务     fetchRegistry: true     serviceUrl:       defaultZone: http://${eureka.instance.hostname}:8761/eureka/   server:     enable-self-preservation: true