Spring Cloud Gateway instance unable to connect to eureka server - spring-boot

Question

I'm following this "Microservices with Spring Boot and Spring Cloud" book by Magnus Larsson, at chapter 10 Spring Cloud Gateway is introduced as an edge server into the microservices landscape, once all the microservices are started SCGateway is unable to connect with the Eureka server:
RedirectingEurekaHttpClient : Request execution error. endpoint=DefaultEndpoint{ serviceUrl='http://eureka:8761/eureka/}, exception=I/O error on POST request for "http://eureka:8761/eureka/apps/GATEWAY": Connect to eureka:8761 [eureka/172.23.0.4] failed: Connection refused; nested exception is org.apache.http.conn.HttpHostConnectException: Connect to eureka:8761 [eureka/172.23.0.4] failed: Connection refused stacktrace=org.springframework.web.client.ResourceAccessException: I/O error on POST request for "http://eureka:8761/eureka/apps/GATEWAY": Connect to eureka:8761 [eureka/172.23.0.4] failed: Connection refused; nested exception is org.apache.http.conn.HttpHostConnectException: Connect to eureka:8761 [eureka/172.23.0.4] failed: Connection refused...
this is the docker-compose.yml file:
version: '2.1'
services:
product:
...instance configuration
recommendation:
...instance configuration
review:
...instance configuration
product-composite:
...instance configuration
mongodb:
...instance configuration
mysql:
...instance configuration
rabbitmq:
...instance configuration
eureka:
build: spring-cloud/eureka-server
mem_limit: 512m
gateway:
environment:
- SPRING_PROFILES_ACTIVE=docker
build: spring-cloud/gateway
mem_limit: 512m
ports:
- "8085:8085"
Eureka Dockerfile:
FROM adoptopenjdk:16_36-jre-hotspot as builder
WORKDIR extracted
ADD ./build/libs/*.jar app.jar
RUN java -Djarmode=layertools -jar app.jar extract
FROM adoptopenjdk:16_36-jre-hotspot
WORKDIR application
COPY --from=builder extracted/dependencies/ ./
COPY --from=builder extracted/spring-boot-loader/ ./
COPY --from=builder extracted/snapshot-dependencies/ ./
COPY --from=builder extracted/application/ ./
EXPOSE 8761
ENTRYPOINT ["java", "org.springframework.boot.loader.JarLauncher"]
Eureka application.yml file:
server:
port: 8761
eureka:
instance:
hostname: localhost
client:
registerWithEureka: false
fetchRegistry: false
serviceUrl:
defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/
# from: https://github.com/spring-cloud-samples/eureka/blob/master/src/main/resources/application.yml
server:
waitTimeInMsWhenSyncEmpty: 0
response-cache-update-interval-ms: 5000
management.endpoints.web.exposure.include: "*"
Spring Cloud Gateway Dockerfile:
FROM adoptopenjdk:16_36-jre-hotspot as builder
WORKDIR extracted
ADD ./build/libs/*.jar app.jar
RUN java -Djarmode=layertools -jar app.jar extract
FROM adoptopenjdk:16_36-jre-hotspot
WORKDIR application
COPY --from=builder extracted/dependencies/ ./
COPY --from=builder extracted/spring-boot-loader/ ./
COPY --from=builder extracted/snapshot-dependencies/ ./
COPY --from=builder extracted/application/ ./
EXPOSE 8085
ENTRYPOINT ["java", "org.springframework.boot.loader.JarLauncher"]
Spring Cloud Gateway application.yml file:
server.port: 8085
spring.application.name: gateway
app.eureka-server: localhost
eureka:
client:
serviceUrl:
defaultZone: http://${app.eureka-server}:8761/eureka/
initialInstanceInfoReplicationIntervalSeconds: 5
registryFetchIntervalSeconds: 5
instance:
leaseRenewalIntervalInSeconds: 5
leaseExpirationDurationInSeconds: 5
spring.cloud.gateway.routes:
- id: product-composite
uri: lb://product-composite
predicates:
- Path=/product-composite/**
- id: product-composite-swagger-ui
uri: lb://product-composite
predicates:
- Path=/openapi/**
- id: eureka-api
uri: http://${app.eureka-server}:8761
predicates:
- Path=/eureka/api/{segment}
filters:
- SetPath=/eureka/{segment}
- id: eureka-web-start
uri: http://${app.eureka-server}:8761
predicates:
- Path=/eureka/web
filters:
- SetPath=/
- id: eureka-web-other
uri: http://${app.eureka-server}:8761
predicates:
- Path=/eureka/**
management.endpoint.health.show-details: "ALWAYS"
management.endpoints.web.exposure.include: "*"
logging:
level:
root: INFO
org.springframework.cloud.gateway.route.RouteDefinitionRouteLocator: INFO
org.springframework.cloud.gateway: TRACE
---
spring.config.activate.on-profile: docker
app.eureka-server: eureka
Originally the project uses Spring Boot version 2.5.2 and Spring Cloud version 2020.0.3, also tried with recent versions (with no success) such as:
Spring Boot version: 2.6.6 and 2.7.5
Spring Cloud: 2021.0.4
The Spring Cloud Gateway is always throwing the same exception:
org.apache.http.conn.HttpHostConnectException: Connect to eureka:8761
[eureka/172.23.0.4] failed: Connection refused
Trying to access the Eureka dashboard or http://localhost:8085/actuator/health endpoint hangs forever.
I'll appreciate any hints or help, thanks in advance.