首先这是官方文档中的介绍和用法：
12.4 Standalone Mode
The combination of the two caches (client and server) and the heartbeats make a standalone Eureka server fairly resilient to failure, as long as there is some sort of monitor or elastic runtime (such as Cloud Foundry) keeping it alive. In standalone mode, you might prefer to switch off the client side behavior so that it does not keep trying and failing to reach its peers. The following example shows how to switch off the client-side behavior:
application.yml (Standalone Eureka Server).
server:
port: 8761
eureka:
instance:
hostname: localhost
client:
registerWithEureka: false
fetchRegistry: false
serviceUrl:
defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/
Notice that the serviceUrl is pointing to the same host as the local instance.
12.5 Peer Awareness
Eureka can be made even more resilient and available by running multiple instances and asking them to register with each other. In fact, this is the default behavior, so all you need to do to make it work is add a valid serviceUrl to a peer, as shown in the following example:
application.yml (Two Peer Aware Eureka Servers).
---
spring:
profiles: peer1
eureka:
instance:
hostname: peer1
client:
serviceUrl:
defaultZone: http://peer2/eureka/
---
spring:
profiles: peer2
eureka:
instance:
hostname: peer2
client:
serviceUrl:
defaultZone: http://peer1/eureka/
In the preceding example, we have a YAML file that can be used to run the same server on two hosts (peer1 and peer2) by running it in different Spring profiles. You could use this configuration to test the peer awareness on a single host (there is not much value in doing that in production) by manipulating /etc/hosts to resolve the host names. In fact, the eureka.instance.hostname is not needed if you are running on a machine that knows its own hostname (by default, it is looked up by usingjava.net.InetAddress).
You can add multiple peers to a system, and, as long as they are all connected to each other by at least one edge, they synchronize the registrations amongst themselves. If the peers are physically separated (inside a data center or between multiple data centers), then the system can, in principle, survive “split-brain” type failures.
在配置文件中配置的信息如下：
spring:
application:
name: eureka-HA
---
spring:
profiles: peer1
eureka:
instance:
hostname: peer1
client:
serviceUrl:
defaultZone: http://peer2:8082/eureka/
server:
port: 8081
---
spring:
profiles: peer2
eureka:
instance:
hostname: peer2
client:
serviceUrl:
defaultZone: http://peer1:8081/eureka/
server:
port: 8082然后在启动类加上@EnableEurekaServer。
准备就绪后通过运行时创建两个实例：
将两个实例全部运行起来，刚开始会报错，在访问eureka网址中也不能看到有客服端注册到上面，需要修改计算机中的C:\Windows\System32\drivers\etc\hosts文件,在文件中加上两个实例的地址。
最后在访问eureka首页看看效果：
有两个客户端注册了，这是相互注册后的结果，到这里就完成了。