Zuul Redirect Issue in Docker container

Question

I am using Grail application and couple of microservices are written which is accessible by grails application. Request comes from grails to Gateway which is on 4000 port. Now based on request gateway will redirect request to respectives services like auth, notification, report, these are the microservices.

Now I am spinning up microservices in docker container, service discovery is on 8761,config server is on 8888, zuul gateway is on 4000 port. Notification service is running on 8755 port and when request comes to Gateway for notification, it redirect first to notification which is working fine for me, as per application flow, notification will validate token hence it will call auth service which is exposed on 8282 port. The moment notification is sending request to auth via gateway its failing ...

everything is working when all services are up and running on 'localhost' this issue is happening when I am starting services in docker container as container will not recognize localhost hence I am changing zuul conifguration as below

zuul:
  ignoredServices: '*'
  host:
    connect-timeout-millis: 120000
    socket-timeout-millis: 120000
  routes:
    notification-service:
      path: /notification/**
      url: http://${NOTIFICATION_SERVICE_HOST:127.0.0.1}:8755
      stripPrefix: true
      sensitiveHeaders:
    report-service:
      path: /report/**
      url: http://${REPORT_SERVICE_HOST:127.0.0.1}:8762
      stripPrefix: true
      sensitiveHeaders:
    p2p-auth-service:
      path: /authService/**
      url: http://${AUTH_SERVICE_HOST:172.17.0.1}:8282
      stripPrefix: true
      sensitiveHeaders:

When request comes to notification, its coming properly, it mean constant which I added NOTIFICATION_SERVICE_HOST is replaced by the IP which I am passing. But same is not happening when its calling auth service where I have given constant AUTH_SERVICE_HOST. Always it is failing with 500 null message.

my docker compose file is as below

version: '3.7'

services:

  configserver:
    image: config
    container_name: configserver
    ports:
      - "8888:8888"
    networks:
      - bridge-abc
    environment:
      SPRING.PROFILES.ACTIVE: native
      EUREKA.CLIENT.SERVICEURL.DEFAULTZONE: http://registry:8761/eureka

  registry:
    image: registry
    container_name: registry
    ports:
      - "8762:8761"
    networks:
      - bridge-abc
    depends_on:
      - configserver
    restart: on-failure
    environment:
      SPRING.PROFILES.ACTIVE: dev
      SPRING.CLOUD.CONFIG.URI: http://configserver:8888/
      EUREKA.CLIENT.SERVICEURL.DEFAULTZONE: http://registry:8761/eureka

  gateway:
    image: gateway
    container_name: gateway
    ports:
      - "4000:4000"
    networks:
      - bridge-abc
    depends_on:
      - configserver
      - registry
    restart: on-failure
    environment:
      SPRING.PROFILES.ACTIVE: dev
      SPRING.CLOUD.CONFIG.URI: http://configserver:8888/
      EUREKA.CLIENT.SERVICEURL.DEFAULTZONE: http://registry:8761/eureka
      REGISTRY_SERVER: registry
      REGISTRY_PORT: 8761
      NOTIFICATION_SERVICE_HOST: 172.17.0.1
      AUTH_SERVICE_HOST: 172.17.0.1

  authservice:
    image: auth-service
    container_name: authservice
    ports:
      - "8282:8282"
    networks:
      - bridge-abc
    depends_on:
      - configserver
      - registry
    restart: on-failure
    environment:
      SPRING.PROFILES.ACTIVE: dev
      SPRING.CLOUD.CONFIG.URI: http://configserver:8888/
      EUREKA.CLIENT.SERVICEURL.DEFAULTZONE: http://registry:8761/eureka
      DB_HOST: 1.2.3.4
      DB_PORT: 1234
      DB_NAME: my-db-name
      DB_USERNAME: user
      DB_PASSWORD: password
      REGISTRY_SERVER: registry
      REGISTRY_PORT: 8761
      

  notification:
    image: notification-service
    container_name: notification
    ports:
      - 8755:8755
    networks:
      - bridge-perfios
    depends_on:
      - configserver
      - registry
    restart: on-failure
    environment:
      SPRING.PROFILES.ACTIVE: dev
      SPRING.CLOUD.CONFIG.URI: http://configserver:8888/
      EUREKA.CLIENT.SERVICEURL.DEFAULTZONE: http://registry:8761/eureka
      REGISTRY_SERVER: registry
      REGISTRY_PORT: 8761
      DB_HOST: 1.2.3.4
      DB_PORT: 1234
      DB_NAME: my-db-name
      DB_USERNAME: user
      DB_PASSWORD: password
      REGISTRY_SERVER: registry
      REGISTRY_PORT: 8761

In above docker compose file I am passing NOTIFICATION_SERVICE_HOST and AUTH_SERVICE_HOST value as 172.17.0.1 so that container can talk to each other, constant AUTH_SERVICE_HOST is not working and always assuming 127.0.0.1 (constant value is not replaced by 172.17.0.1, always it is assuming 127.0.0.1) whereas constant NOTIFICATION_SERVICE_HOST works properly and this constant value is replaced by 172.17.0.1

I am not sure what is wrong here or please suggest if some configuration is missing or I am doing any mistakes.

Answer 1

I have resolved this issue, problem was happening in each microservice where it was validating token, to do this; it will go to gateway and then request will redirect to auth service. While resolving DNS name in each microservice it was mapping with default IP ie 127.0.0.1. I have changed each miceroservice's container /etc/hosts as below

172.17.0.1 'my domain name' 

and this resolved my issue.
Now I need to understand how I can make it generic so that if I remove container and run again docker-compose up then below details should auto update to container's host file

172.17.0.1 'my domain name'

Any suggestion is much appreciable.