I have a very simple demo of using Spring Boot + Docker Compose + Eureka.
My server runs on port 8671 with the following application properties:
server: port: 8761 eureka: instance: prefer-ip-address: true client: registerWithEureka: false fetchRegistry: false server: waitTimeInMsWhenSyncEmpty: 0
My Eureka client runs on port 9000 with the following application properties:
server: port: 9000 spring: application: name: user-registration eureka: client: registerWithEureka: true fetchRegistry: true serviceUrl: defaultZone: http://localhost:8761/eureka/ instance: prefer-ip-address: true
When I start up my docker.compose file in the parent maven project, this is the contents of my docker-compose file:
eureka-server: image: rosenthal/eureka-server ports: - "8761:8761" user-registration: image: rosenthal/user-registration ports: - "9000:9000" links: - eureka-server
When I run my application by first starting the eureka server, following by the client via
The server successfully registers my client (I call it user-registration).
When I run my application through docker-compose, the client fails to register with the following output:
DiscoveryClient_USER-REGISTRATION/0fd640cbc3ba:user-registration:9000: registering service... user-registration_1 | 2017-06-21 04:36:05.120 ERROR 1 --- [nfoReplicator-0] c.n.d.s.t.d.RedirectingEurekaHttpClient : Request execution error user-registration_1 | user-registration_1 | com.sun.jersey.api.client.ClientHandlerException: java.net.ConnectException: Connection refused (Connection refused)
My first assumption was that running docker-compose ran into a race condition on waiting for the server to start, but my eureka client seems to have a heartbeat trying to call home to the server it’s configured with. This means it’s just not able to find the Eureka server I have registered (and is running, I can navigate to it on localhost:8671).
What am I missing here? Everything runs fine running locally with spring-boot starting up with it’s own embedded tomcat containers. As soon as I start to do it with docker-compose, it doesn’t want to work.
I realized my problem, I believe. So docker doesn’t run on localhost, it runs on the public IP it is assigned when I start up docker. Navigating to this ip + port shows my service running for Eureka Server. The client still doesn’t register.
SO, I made changes to the application.yml file for my eureka client to:
serviceUrl: defaultZone: http://192.168.59.103:8761/eureka/
That IP is the one my docker daemon is running under. Now, it misses the first registration when I do docker-compose, but the second heartbeat picks up my client.
How can I ensure the client waits until the server is FULLY up? I used the proper docker “links” field in my docket compose file, but it didn’t work as I hoped. Additionally, how can I see the defaultZone file to be my DOCKER_HOST IP?
The resulting docker-compose file that got everything working for me was:
eureka-server: image: thorrism/eureka-server ports: - "8761:8761" user-registration: image: thorrism/user-registration ports: - "9000:9000" links: - eureka-server environment: EUREKA_CLIENT_SERVICEURL_DEFAULTZONE: http://eureka-server:8761/eureka
If useful for you, that’s in some way how I configure it for my production environment (docker-compose file version 2):
version: '2' services: eureka-server: image: rosenthal/eureka-server expose: - "8761" user-registration: image: rosenthal/user-registration container_name: user-registration ports: - "9000:8080" environment: server.port: 8080 eureka.client.enabled: 'true' eureka.host: eureka-server eureka.instance.preferIpAddress: 'true'
From the docs that’s what
Expose ports without publishing them to the host machine – they’ll only be accessible to linked services. Only the internal port can be specified.
As you’ve got everything in the same network, containers can see each other with no links between them.
Keep in mind that with this configuration port 9000 will be publicly accessible at the host machine, and mapped to the 8080 port of the user-registration container.