Microservice - Spring Cloud Netflix Eureka Service Registry

Let’s go ahead and create our service registry project (terawarehouse-service-discovery). A service registry like Netflix Eureka is a fixed ...

Let’s go ahead and create our service registry project (terawarehouse-service-discovery). A service registry like Netflix Eureka is a fixed point that allows the services to find and communicate with each other without knowing the hostname nor the port but with only the Spring application name. Eureka enables client-side load balancing and with a peer setup each client can act as a server as each client communicates and synchronize with each other.

Let’s start with:

1. Setting up the Eureka Server - terawarehouse-service-discovery
2. Create a new SpringBoot project.
3. Add dependency to spring-cloud-starter-netflix-eureka-server which will provide the necessary dependencies to make this project a service registry server.
4. Add dependencies spring-boot-starter-web and spring-boot-starter-actuator to let us display the server information.
5. Annotate SpringBootApplication with EnableEurekaServer.
6. Create an application.yml configuration file with 2 profiles. Notice that I use different network IP for each profile. Don’t register the eureka server as a client.
1. instance1 - which we will deploy on our machine
2. instance2 - which we will deploy on another machine
7. Run the config server.
8. Run 2 instances with different profiles.
9. Check that they are a replica of each other.

Configuring the Client 

1. Add dependency to spring-cloud-starter-netflix-eureka-client. This will provide the needed dependencies for this project to connect to the service discovery server.
2. Annotate the SpringBoot class with EnableDiscoveryClient.
3. And finally add the eureka client information to our project’s configuration:
   eureka.client.register-with-eureka: true
   eureka.client.fetch-registry: true
   eureka.client.service-url.defaultZone:
   http://192.168.1.100:8761/eureka,http://192.168.1.101:8761/eureka
   eureka.client.instance.prefer-ip-address: true
   eureka.client.instance.ip-address: 192.168.1.100
4. Run the client.
5. Check if the client properly registers with the eureka server.

Later on, as we introduce new microservices (inventory, order, etc) we can use this service registry for the catalog to send a request to the inventory or simply allow REST communication between them with only the spring application name.

In the next lesson, we will introduce a server-side load balancer that will receive the requests from a client and forward it to the appropriate API using the service discovery information.

I hope everything is clear to this point. You can always ask questions in the comment section below and I’ll be sure to address them.

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References

• https://spring.io/guides/gs/service-registration-and-discovery/

Repositories

• https://github.com/orgs/broodcamp
• https://github.com/orgs/terawarehouse