eureka

Spring Boot Eureka Demo

Simple demo of service registration and discovery using Eureka.

Initial work based on this guide:

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

Assumptions

• maven installed (brew install maven)
• CF deployed with cf-networking-release (The examples assume a bosh-lite deployment)
• CF CLI installed, using version 6.30.0 or higher.

Build the applications

There are 4 applications:

• registry: The Eureka Service Registry
• backend: A simple web service that registers with the registry
• frontend: A web app that locates the backend via the registry
• zuul-proxy: A web proxy that forwards requests to services in the registry

./build

Push the applications

The manifest.yml includes all 4 applications.

cf push

Container Networking

The backend is configured with the no-route:true property to disable accessing it via the go-router. In order for the zuul-proxy or the frontend to reach it, policies must be added.

Allow access from frontend to backend

cf add-network-policy frontend --destination-app backend --protocol tcp --port 8080

http://frontend.bosh-lite.com/

should have the same response:

{
  springApplicationName: "backend",
  serverPort: "8080"
}

Allow access from zuul-proxy to backend

cf add-network-policy zuul-proxy --destination-app backend --protocol tcp --port 8080

http://zuul-proxy.bosh-lite.com/backend/whoami

should respond with:

{
  springApplicationName: "backend",
  serverPort: "8080"
}

In addition to the /whoami, the following actuator endpoints are also available:

• /backend/instances
• /backend/health
• /backend/metrics
• /backend/mappings

Remove access

cf remove-network-policy zuul-proxy --destination-app backend --protocol tcp --port 8080
cf remove-network-policy frontend --destination-app backend --protocol tcp --port 8080

More Details

These properties are set to have the backend register with it's IP address in the file backend/src/main/resources/application.properties:

eureka.client.preferIpAddress=true
eureka.instance.hostname=${CF_INSTANCE_INTERNAL_IP}
eureka.instance.nonSecurePort=${PORT}

This causes the backend instance to report its own address as the internal container-network address and port (not the external, NAT'ed address that the router uses to reach it).

The backend reaches the registry at the public address registry.bosh-lite.com. The zuul-proxy is also configured to look up services registered in eureka at this address. Edit this address if deploying to a CF on a different domain.

Note that the apps are using the default, Diego-assigned port 8080.