Getting docker containers to communicate with each other-CodePudding

I have been working on a dev project with a quarkus server running on my machine. I have a keycloak and postgres instances both running on docker containers. The current setup is that I have a docker-compose file for keycloak and postgres and I run quarkus from the CLI. All 3 processes can communicate with one another.

I am now at the point where I want to package up my quarkus application into a docker container and host it on the cloud, along with postgres and keycloak. Problem is I am having great difficulty in getting the app to communicate with the db and keycloak and I can only assume it is a docker networking issue....

docker-compose.yml

version: "3.3"
services:
  keycloak:
    image: jboss/keycloak:13.0.1
    environment:
      KEYCLOAK_USER: admin
      KEYCLOAK_PASSWORD: password
      DB_VENDOR: postgres
      DB_ADDR: postgres_db
      DB_DATABASE: name
      DB_SCHEMA: keycloak
      DB_USER: admin
      DB_PASSWORD: password
      KEYCLOAK_IMPORT: /tmp/keycloak-realm.json
    volumes:
      - ./keycloak-realm.json:/tmp/keycloak-realm.json
    depends_on:
      - postgres_db
    ports:
      - "8180:8080"
    networks:
      - whole_network

  postgres_db:
    build: postgres/.
    environment:
      POSTGRES_PASSWORD: password
      POSTGRES_USER: admin
      POSTGRES_DB: name
    volumes:
      - ./postgres_data:/var/lib/postgresql/data
    ports:
      - "5432:5432"
    healthcheck:
      test: ["CMD-SHELL", "sudo pg_isready -U postgres"]
      interval: 10s
      timeout: 5s
      retries: 5
    networks:
      - whole_network

networks:
  whole_network:
    driver: bridge

application.properties

quarkus.http.test-port=8888
quarkus.resteasy.path=/api/v1
quarkus.http.cors=true

quarkus.oidc.auth-server-url=http://keycloak:8180/auth/realms/realm
quarkus.oidc.client-id=candledata
quarkus.oidc.application-type=SERVICE
quarkus.http.auth.permission.authenticated.paths=/*
quarkus.http.auth.permission.authenticated.policy=authenticated

quarkus.datasource.db-kind=postgresql
quarkus.datasource.jdbc.url=jdbc:postgresql://postgres_db:5432/name?sslmode=disable
quarkus.datasource.username=admin
quarkus.datasource.password=password
quarkus.liquibase.migrate-at-start=true
quarkus.liquibase.change-log=db/changelog/db.changelog-master.xml
quarkus.hibernate-orm.database.generation=drop-and-create

On the app.props file I originally had the urls as localhost but changed them to the container name when I was putting the quarkus app into a container.

The Dockerfile is just a standard one that comes with all quarkus projects. But the commands I use to build the image and run the container are;

mvn package -DskipTests=true
docker build -f src/main/docker/Dockerfile.jvm -t backend .
docker run -i --rm -p 8888:8888 --network=cd_whole_network backend

When I run I get the following output;

exec java -Dquarkus.http.host=0.0.0.0 -Djava.util.logging.manager=org.jboss.logmanager.LogManager -XX: ExitOnOutOfMemoryError -cp . -jar /deployments/app.jar
__  ____  __  _____   ___  __ ____  ______
 --/ __ \/ / / / _ | / _ \/ //_/ / / / __/
 -/ /_/ / /_/ / __ |/ , _/ ,< / /_/ /\ \
--\___\_\____/_/ |_/_/|_/_/|_|\____/___/
2021-09-29 07:32:13,750 ERROR [io.qua.run.Application] (main) Failed to start application (with profile prod): java.net.ConnectException: Connection refused
    at java.base/sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
    at java.base/sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:777)
    at io.netty.channel.socket.nio.NioSocketChannel.doFinishConnect(NioSocketChannel.java:330)
    at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:334)
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:702)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:650)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:576)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493)
    at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
    at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
    at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
    at java.base/java.lang.Thread.run(Thread.java:829)

Googling the specific didn't prove much use for me. I assumed with all 3 containers on the one network, they would be able to communicate with one another but that is also not the case. Any help/advice on this would be greatly appreciated

CodePudding user response：

You are using the wrong port for keycloak in your application configuration.
You have this configuration :

quarkus.oidc.auth-server-url=http://keycloak:8180/auth/realms/realm

However, in your docker-compose file, for the keycloak service, you have this

ports:
      - "8180:8080"

This means that you can reach keycloak on port 8180 from your host and on port 8080 from the container. As you're using docker network to reach your service, then you should use port 8080 to reach keycloak.