Spring boot client doesn't register to Spring admin on docker

Question

Hello to all developers.

I have a problem and I have been struggling with it for a few days but I can not solve it.

The problem is I have two dockerized Spring application, one of them is admin and another is client. When I run these two out of Docker, the client registers with the admin without any problem, and I can see the client from the admin dashboard. But when I try to run these two as two containers in Docker with a Docker network, the client application gives this error:

de.codecentric.boot.admin.client.registration.DefaultApplicationRegistrator: Failed to register application as Application(name=spring client, managementUrl=http://545ade59e8dc:8585/actuator, healthUrl=http://545ade59e8dc:8585/actuator/health, serviceUrl=http://545ade59e8dc:8585/) at spring-boot-admin ([http://localhost:8080/instances]): I/O error on POST request for "http://localhost:8080/instances": Connection refused; nested exception is java.net.ConnectException: Connection refused. Further attempts are logged on DEBUG level

The admin application's docker-compose.yml file:

version: '3.3'

networks:
  spring-admin-network:
    driver: bridge

services:
  spring-admin:
    build:
      context: .
      args:
        JAR_FILE: "./target/spring-admin-1.0.0.jar"
    image: spring-admin
    container_name: spring-admin
    ports:
      - "127.0.0.1:8080:8585"
    networks:
      - spring-admin-network

And the client application's docker-compose.yml file:

version: '3.3'

networks:
  spring-admin-network:
    driver: bridge

services:
  repo-reporter:
    build:
      context: .
      args:
        JAR_FILE: "./target/spring-client-1.0.0.jar"
    image: spring-client
    container_name: spring-client
    ports:
      - "127.0.0.1:8081:8585"
    networks:
      - spring-admin-network

And application.properies for admin application:

spring.application.name=spring-admin
server.port=8585
spring.security.user.name=admin
spring.security.user.password=admin

And application.properies for client application:

spring.application.name=spring-client
server.port=8585
server.compression.enabled=true
server.http2.enabled=true
management.endpoints.web.exposure.include=*
management.endpoint.health.show-details=always
spring.boot.admin.client.url=http://localhost:8080
spring.boot.admin.client.username=admin
spring.boot.admin.client.password=admin
spring.boot.admin.client.instance.metadata.user.name=${spring.security.user.name}
spring.boot.admin.client.instance.metadata.user.password=${spring.security.user.password}

The commands I execute:

docker network create spring-admin-network
...Some hash...

cd /spring-admin

docker-compose build
...Successfully built...

docker-compose up -d
...Creating network "springadmin_spring-admin-network" with driver "bridge"
Creating spring-admin ... done...

cd ../spring-client

docker-compose build
...Successfully built...

docker-compose up -d
...Creating network "springclient_spring-admin-network" with driver "bridge"
Creating spring-client ... done...

docker logs -f spring-client
.
.
.
de.codecentric.boot.admin.client.registration.DefaultApplicationRegistrator: Failed to register application as Application(name=spring client, managementUrl=http://545ade59e8dc:8585/actuator, healthUrl=http://545ade59e8dc:8585/actuator/health, serviceUrl=http://545ade59e8dc:8585/) at spring-boot-admin ([http://localhost:8080/instances]): I/O error on POST request for "http://localhost:8080/instances": Connection refused; nested exception is java.net.ConnectException: Connection refused. Further attempts are logged on DEBUG level

Thanks in advance.

Answer 1

Docker creates a new docker network when you build and run the docker-compose file. as an example

xxx_spring-admin-network (for admin application)

yyy_spring-admin-network (for client application)

you can check by

docker network ls

First and foremost, you should set up a Docker network.

docker network create spring-admin-network

then make a docker-compose.yml change Both files should point to an existent network.

version: '3.3'

networks:
   spring-admin-network:
   external: true
...