Registration and discovery of Spring Cloud services Eureka

Spring Cloud

Service registration and discovery

Use of Eureka Server

1. add dependencies
2. The startup class is added to @EnableEurekaServer

3. Add the following to the configuration file

   server：
       port： 8761
   
   eureka:
       client:
           registerWithEureka: false
           fetchRegistry: false
           serviceUrl:
               defaultZone: http://localhost:8761/eureka/

   Configuration instructions

   • registerWithEureka: Whether to register itself to the server, the default is true. The current service does not need to register itself to itself.
   • fetchRegistry: Whether to obtain registration information from Eureka Server, the default is true. It is currently a single-point Eureka Server and does not need to synchronize other nodes.
   • defaultZone: Set the address for interacting with Eureka Server. The query and registration services rely on this address. Multiple addresses are separated by commas.
4. Startup project. Visit http://localhost:8761/ to see the list of registered services

Use of Eureka Client

1. add dependencies

2. Add the following to the configuration file

   spring:
       application:
           name: xxxxxx
   
   euraka:
       client:
           serverUrl: http://localhost:8761/eureka/
       instance:
           prefer-ip-address: true 

   Configuration instructions

   • name: the name registered to the Eureka Server
   • prefer-ip-address: Whether to register your own IP with Eureka Server. Default false, use the hostname of the operating system to register

3. Startup class adding @EnableDiscoveryClient(discover: discover) or @EnableEurekaClient

   illustrate:

   • @EnableDiscoveryClient is an abstract interface that can be used with other service components. Such as: Zookeeper, Consul, etc.
   • @EnableEurekaClient is an Eureka-specific annotation

Eureka Server cluster

• Eureka Server can implement a cluster by running multiple instances to register with each other.

  Modify the configuration file:

  spring:
      application:
  
          name: eureka-server-cluster
  ---
  
  spring:
      profiles: cluster1
  server:
      post: 8761
  eureka:
      instance:
          hostname: cluster1
      client:
          serverUrl:
  
              defaultZone: http://localhost:8762/eureka/
  ---
  
  spring:
      profiles: cluster2
  server:
      port: 8762
  erueka:
      instance:
          hostname: cluster2
      client:
          serverUrl:
              defaultZone: http://localhost:8761/eureka/

  Description: Use a hyphen (-) to divide application.yml into three parts. The first part does not declare that profiles are globally effective.

• Run the program.

  java -jar eureka-server-cluster.jar –spring.profiles.active=clusert1
  java -jar eureka-server-cluster.jar –spring.profiles.active=clusert2

Eureka Client register cluster

Even if Client registers a single node, Eureka Server can synchronize with each other. It is recommended to configure multiple nodes.