Docker compose无法访问其他容器的端口

Question

I have 2 containers running with docker compose. One of the containers is executing a shell script which should check if the other container has already started and is running on port 9990.

Even though the container is starting, the shell script echos nothing.

   keycloak:
      image: jboss/keycloak:latest
      volumes: 
        - ./imports/cache_reload/disable-theme-cache.cli:/opt/jboss/startup-scripts/disable-theme-cache.cli
        - ./imports/themes/custom/:/opt/jboss/keycloak/themes/custom-theme/
        - ./imports/realm/realm-export.json:/opt/jboss/realms/custom-import.json
      environment:
        DB_VENDOR: MYSQL
        DB_ADDR: mysql
        DB_DATABASE: keycloak
        DB_USER: keycloak
        DB_PASSWORD: password
        KEYCLOAK_USER: admin
        KEYCLOAK_PASSWORD: Pa55w0rd
      ports:
        - 8080:8080
      depends_on:
        - mysql
  keycloak_installer:
    image: solr:6.6-alpine
    volumes:
      - ./imports/scripts/import-realm.sh:/docker-entrypoint-initdb.d/init.sh
    depends_on: 
      - keycloak

The shell script is the following:

echo "MOIN LEUDE TRYMACS HIER!"

while ! nc -z localhost 9990; do
    sleep 1
    echo "Waiting for keycloak server startup 9990..."

    echo "$(nc -z localhost 9990)"
done

The first echo is printed, but then nothing else is printed.

The container keycloak is running on Port 9990.

Please help, thanks

Answer 1

You have to understand more detail about network in docker compose.

To solve your issue, you need:

1. Add network in your docker compose file for each container (there is a default network but to understand the mechanism, you can define it explicitly). This must looks like this (under ports for example) for the first container (named keycloak ):

     ports:
       - 8080:8080  
     networks:
       - keycloak_network

On the second container (named keycloak_installer ) (you must expose the port that you want to request in the first container):

    depends_on: 
      - keycloak
    networks:
      - keycloak_network

2. On your script call explictly the second container which will be now available by the network. You must change your code by this:

    nc -z keycloak_installer 9990