spring boot eureka with docker gets connection refused - spring-boot

Question

I have a multi-service platform working locally. It uses Spring Boot 2.7, Spring Eureka Docker, and Feign for inter-service calls. Now that I have it all starting up via Docker Compose, the services seem to fail when trying to request each other. Yet, I see all services registered on Eureka dashboard:
When I receive a call in the API-GATEWAY, it calls the IDENTITY-SERVICE.
The caller looks like this:
The main class has:
#SpringBootApplication
#EnableDiscoveryClient
#EnableFeignClients("com.xxx.apigateway.service.feign")
public class ApiGatewayApplication {
...
}
The service to call the other service is:
#FeignClient(name = "identity-service")
public interface IdentityServiceClient {
#RequestMapping(method = RequestMethod.GET, value = "/api/{scannedId}")
ApiKey getApiKey(#PathVariable String scannedId);
}
And the application.properties file for (all services is basically the same) is:
server.port=8081
eureka.client.serviceUrl.defaultZone=http://eureka:#discovery-service:8010/eureka
eureka.client.register-with-eureka=true
eureka.instance.instance-id=${spring.application.name}:${spring.application.instance_id:${random.value}}
eureka.instance.hostname=${HOST_NAME:localhost}
spring.config.import=optional:configserver:http://config-service:8888
spring.cloud.config.uri=http://config-service:8888
spring.cloud.config.name=config-service
spring.cloud.config.discovery.enabled = false
spring.main.web-application-type=reactive
here is part of the docker-compose:
discovery-service:
container_name: discovery-service
image: discovery-service
pull_policy: never
environment:
- SPRING_PROFILES_ACTIVE=docker
expose:
- "8010"
ports:
- "8010:8010"
restart: unless-stopped
networks:
- mynet
api-gateway:
container_name: api-gateway
image: api-gateway
pull_policy: never
environment:
- SPRING_PROFILES_ACTIVE=docker
expose:
- "8081"
ports:
- "8081:8081"
restart: unless-stopped
depends_on:
- config-service
- discovery-service
identity-service:
container_name: identity-service
image: identity-service
pull_policy: never
environment:
- SPRING_PROFILES_ACTIVE=docker
restart: unless-stopped
depends_on:
- config-service
- discovery-service
- api-gateway
And the error thrown by the API_GATEWAY when trying to make the call to the IDENTITY-SERIVCE is:
api-gateway | 2022-09-28 15:10:00.889 DEBUG 1 --- [nio-8081-exec-1] u.f.m.a.s.feign.IdentityServiceClient : [IdentityServiceClient#getAllApiKeys] ---> GET http://identity-service/api/all HTTP/1.1
api-gateway | 2022-09-28 15:10:00.889 DEBUG 1 --- [nio-8081-exec-1] u.f.m.a.s.feign.IdentityServiceClient : [IdentityServiceClient#getAllApiKeys] ---> END HTTP (0-byte body)
api-gateway | 2022-09-28 15:10:00.939 WARN 1 --- [nio-8081-exec-1] o.s.c.l.core.RoundRobinLoadBalancer : No servers available for service: identity-service
api-gateway | 2022-09-28 15:10:00.942 DEBUG 1 --- [nio-8081-exec-1] u.f.m.a.s.feign.IdentityServiceClient : [IdentityServiceClient#getAllApiKeys] <--- HTTP/1.1 503 (51ms)
api-gateway | 2022-09-28 15:10:00.942 DEBUG 1 --- [nio-8081-exec-1] u.f.m.a.s.feign.IdentityServiceClient : [IdentityServiceClient#getAllApiKeys]
api-gateway | 2022-09-28 15:10:00.942 DEBUG 1 --- [nio-8081-exec-1] u.f.m.a.s.feign.IdentityServiceClient : [IdentityServiceClient#getAllApiKeys] Load balancer does not contain an instance for the service identity-service
api-gateway | 2022-09-28 15:10:00.942 DEBUG 1 --- [nio-8081-exec-1] u.f.m.a.s.feign.IdentityServiceClient : [IdentityServiceClient#getAllApiKeys] <--- END HTTP (75-byte body)
api-gateway | 2022-09-28 15:10:00.942 ERROR 1 --- [nio-8081-exec-1] u.f.m.a.service.feign.FeignErrorDecoder : decode exception method: IdentityServiceClient#getAllApiKeys()
api-gateway | 2022-09-28 15:10:00.942 ERROR 1 --- [nio-8081-exec-1] u.f.m.a.service.feign.FeignErrorDecoder : Feign error: HTTP/1.1 503
api-gateway |
api-gateway | feign.Response$ByteArrayBody#7d9a6870
api-gateway | 2022-09-28 15:10:00.942 ERROR 1 --- [nio-8081-exec-1] u.f.m.a.service.feign.FeignErrorDecoder : Throwing exception: null
**...**
api-gateway | feign.RetryableException: Connection refused executing GET http://identity-service/api/all
api-gateway | at feign.FeignException.errorExecuting(FeignException.java:268) ~[feign-core-11.8.jar:na]
api-gateway | Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException:
api-gateway | Error has been observed at the following site(s):
api-gateway | *__checkpoint ⇢ org.springframework.web.filter.reactive.ServerWebExchangeContextFilter [DefaultWebFilterChain]
api-gateway | *__checkpoint ⇢ org.springframework.cloud.gateway.filter.WeightCalculatorWebFilter [DefaultWebFilterChain]
api-gateway | *__checkpoint ⇢ HTTP GET "/providers/b691eda6-f021-4534-8b4d-aaa5a27584d" [ExceptionHandlingWebHandler]
api-gateway | Original Stack Trace:
api-gateway | at feign.FeignException.errorExecuting(FeignException.java:268) ~[feign-core-11.8.jar:na]
**...**
api-gateway | Caused by: java.net.ConnectException: Connection refused
Since this works outside of Docker Compose, I assume that is the culprit, but I don't for sure and how to fix this.

Answer 1

I faced the same problem before.
By adding this:
eureka.instance.prefer-ip-address=true
and removing this:
# eureka.instance.hostname=${HOST_NAME:localhost}
worked for me.