I cannot figure out why my docker databases will not connect with the microservices- Spring Boot

[Nathan Milota]

I am trying to get my docker SQL databases connected to my microservices, but I keep getting exceptions that the connection failed.  I cannot figure out why.  

I have the docker-compose.yml here.

version: '3' services:  ## MySQL Docker Compose Config  postgres-order:    container_name: postgres-order    image: postgres    environment:      POSTGRES_DB: order-service      POSTGRES_USER: ptechie      POSTGRES_PASSWORD: password      PGDATA: /data/postgres    volumes:      - ./postgres-order:/data/postgres    expose:      - "5431"    ports:      - "5431:5431"    command: -p 5431    restart: unless-stopped  postgres-inventory:    container_name: postgres-inventory    image: postgres    environment:      POSTGRES_DB: inventory-service      POSTGRES_USER: ptechie      POSTGRES_PASSWORD: password      PGDATA: /data/postgres    volumes:      - ./postgres-inventory:/data/postgres    ports:      - "5432:5432"    restart: unless-stopped  ## Mongo Docker Compose Config  mongo:    container_name: mongo    image: mongo:4.4.14-rc0-focal    restart: unless-stopped    ports:      - "27017:27017"    expose:      - "27017"    volumes:      - ./mongo-data:/data/db  ## Keycloak Config with Mysql database  keycloak-mysql:    container_name: keycloak-mysql    image: mysql:5.7    volumes:      - ./mysql_keycloak_data:/var/lib/mysql    environment:      MYSQL_ROOT_PASSWORD: root      MYSQL_DATABASE: keycloak      MYSQL_USER: keycloak      MYSQL_PASSWORD: password  keycloak:    container_name: keycloak    image: quay.io/keycloak/keycloak:18.0.0    command: [ "start-dev", "--import-realm" ]    environment:      DB_VENDOR: MYSQL      DB_ADDR: mysql      DB_DATABASE: keycloak      DB_USER: keycloak      DB_PASSWORD: password      KEYCLOAK_ADMIN: admin      KEYCLOAK_ADMIN_PASSWORD: admin    ports:      - "8080:8080"    volumes:      - ./realms/:/opt/keycloak/data/import/    depends_on:      - keycloak-mysql  zookeeper:    image: confluentinc/cp-zookeeper:7.0.1    container_name: zookeeper    environment:      ZOOKEEPER_CLIENT_PORT: 2181      ZOOKEEPER_TICK_TIME: 2000  broker:    image: confluentinc/cp-kafka:7.0.1    container_name: broker    ports:      - "9092:9092"    depends_on:      - zookeeper    environment:      KAFKA_BROKER_ID: 1      KAFKA_ZOOKEEPER_CONNECT: 'zookeeper:2181'      KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: PLAINTEXT:PLAINTEXT,PLAINTEXT_INTERNAL:PLAINTEXT      KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://localhost:9092,PLAINTEXT_INTERNAL://broker:29092      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1      KAFKA_TRANSACTION_STATE_LOG_MIN_ISR: 1      KAFKA_TRANSACTION_STATE_LOG_REPLICATION_FACTOR: 1  ## Zipkin  zipkin:    image: openzipkin/zipkin    container_name: zipkin    ports:      - "9411:9411"  # Eureka Server  discovery-server:    image: kenm66/discovery-server:latest    container_name: discovery-server    pull_policy: always    ports:      - "8761:8761"    environment:      - SPRING_PROFILES_ACTIVE=docker    depends_on:      - zipkin  api-gateway:    image: kenm66/api-gateway:latest    container_name: api-gateway    pull_policy: always    ports:      - "8181:8080"    expose:      - "8181"    environment:      - SPRING_PROFILES_ACTIVE=docker      - LOGGING_LEVEL_ORG_SPRINGFRAMEWORK_SECURITY= TRACE    depends_on:      - zipkin      - discovery-server      - keycloak   #Product-Service Docker Compose Config  product-service:    container_name: product-service    image: kenm66/product-service:latest    pull_policy: always    environment:      - SPRING_PROFILES_ACTIVE=docker    depends_on:      - mongo      - discovery-server      - api-gateway  ## Order-Service Docker Compose Config  order-service:    container_name: order-service    image: kenm66/order-service:latest    pull_policy: always    environment:      - SPRING_PROFILES_ACTIVE=docker      - SPRING_DATASOURCE_URL=jdbc:postgresql://postgres-order:5431/order-service        depends_on:      - postgres-order      - broker      - zipkin      - discovery-server      - api-gateway  ## Inventory-Service Docker Compose Config  inventory-service:    container_name: inventory-service    image: kenm66/inventory-service:latest    pull_policy: always    environment:      - SPRING_PROFILES_ACTIVE=docker      - SPRING_DATASOURCE_URL=jdbc:postgresql://postgres-inventory:5432/inventory-service        depends_on:     - postgres-inventory      - discovery-server      - api-gateway  ## Notification-Service Docker Compose Config  notification-service:    container_name: notification-service    image: kenm66/notification-service:latest    pull_policy: always    environment:      - SPRING_PROFILES_ACTIVE=docker    depends_on:      - zipkin      - broker      - discovery-server      - api-gateway


This is my application.properties file for the inventory service.  

server.port=8080 spring.datasource.url=jdbc:postgresql://postgres:5432/inventory-service spring.datasource.driver-class-name=org.postgresql.Driver spring.datasource.username=ptechie spring.datasource.password=password spring.zipkin.base-url=http://zipkin:9411 eureka.client.serviceUrl.defaultZone=http://eureka:password@discovery-server:8761/eureka



The service for the SQL launches and is in a container working, but my inventory service in Spring Boot will not connect to it.

[Tim Holloway]

I can't give a simple answer here, but a few notes might help.

I've never seen "expose" as a run parameter for Docker, only in Dockerfiles. I'm not sure what that's all about, but it might be blocking access when you thought you were granting it.

Docker has several networking. The simplest is to merely let the containers share the same network as the host. A popular alternative is to let Docker set up a VPN between containers, however, and that's quite common when you have service containers with their own private database.