docker 中的 Eureka 客户端未与 Eureka 服务器连接

Question

I have one eureka server.

server:
  port: 8761
eureka:
  client:
    registerWithEureka: false
    fetchRegistry: false

I have one eureka client.

spring:
  application:
    name: mysearch
server:
  port: 8020
eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka
  instance:
    preferIpAddress: true

My eureka client is running in a docker container.

FROM java:8
COPY ./mysearch.jar /var/tmp/app.jar
EXPOSE 8180
CMD ["java","-jar","/var/tmp/app.jar"]

I am starting the eureka server by java -jar eureka-server.jar After that I am starting the docker instance of the eureka client using sudo docker build -t web . and sudo docker run -p 8180:8020 -it web . I am able to access the eureka client and server from browser but the client is not connecting with Eureka server. I am not able to see the client in the eureka server dashboard. I am getting below errors and warnings.

WARN 1 --- [tbeatExecutor-0] c.n.d.s.t.d.RetryableEurekaHttpClient    : Request execution failed with message: java.net.ConnectException: Connection refused (Connection refused)
ERROR 1 --- [tbeatExecutor-0] com.netflix.discovery.DiscoveryClient    : DiscoveryClient_FLIGHTSEARCH/98b0d95fd668:flightsearch:8020 - was unable to send heartbeat!
INFO 1 --- [nfoReplicator-0] com.netflix.discovery.DiscoveryClient    : DiscoveryClient_FLIGHTSEARCH/98b0d95fd668:flightsearch:8020: registering service...
ERROR 1 --- [nfoReplicator-0] c.n.d.s.t.d.RedirectingEurekaHttpClient  : Request execution error
WARN 1 --- [nfoReplicator-0] c.n.d.s.t.d.RetryableEurekaHttpClient    : Request execution failed with message: java.net.ConnectException: Connection refused (Connection refused)
WARN 1 --- [nfoReplicator-0] com.netflix.discovery.DiscoveryClient    : DiscoveryClient_FLIGHTSEARCH/98b0d95fd668:flightsearch:8020 - registration failed Cannot execute request on any known server
WARN 1 --- [nfoReplicator-0] c.n.discovery.InstanceInfoReplicator     : There was a problem with the instance info replicator

I am doing it in an AWS EC2 Ubuntu instance. Can anyone please tell me what I am doing wrong here?

Answer 1

server:
  ports:
      - "8761:8761"
eureka:
  client:
    registerWithEureka: false
    fetchRegistry: false

with the above changes port 8761 will expose on host and can connect to server. as your connecting using localhost " http://localhost:8761/eureka " which is searching for port 8761 on host.

In Eureka client config use host ip instead of localhost , because if localhost used it's search for port 8761 within container

http://hostip:8761/eureka

Answer 2

Make sure you are running in Swarm mode.(Single node can also run Swarm)

$ docker swarm init

An overlay network is created so services can ping each other.

$ docker network create -d overlay mybridge

Set application.property for eurika client as below

eureka.client.service-url.defaultZone=http://discovery:8761/eureka

Now create first discovery service (Eureka discover server)

$ docker service create  -d --name discovery --network mybridge \
    --replicas 1 -p 8761:8761 server-discovery

Open your browser and hit any node with port 8761

Now create client service:

$ docker service create  -d --name goodbyeapp --network mybridge \
    --replicas 1 -p 2222:2222 goodbye-service

This will register to the discovery service.

Answer 3

In the container world, the eureka server ip address can change each time the eureka server is restarted. Hence specifying the host ip address for eureka server url doesn't work all the time.

In the docker-compose.yml, I had to link the eureka client service to the eureka server container. Until I link the services, eureka client couldn't connect to the server.

This is already answered in another post recently: Applications not registering to eureka when using docker-compose