docker - Communicating Between Containers through localhost

Question

I'm attempting to containerize an application that depends on Kafka but I'm running into issues with my application attempting to establish a connection with Kafka on localhost:9092 once they are running in containers.

The stack has 2 containers that need to communicate with each other defined in the docker-compose file below. I'm creating a new network kafka-net using the bridge driver.

version: '3.0'

networks:
  kafka-net:
    driver: bridge

services:
  spotify-kafka:
    image: 'spotify/kafka'
    container_name: 'spotify-kafka'
    networks:
      - kafka-net
    ports:
      - '2181:2181'
      - '9092:9092'
    environment:
      - ADVERTISED_HOST=localhost
      - ADVERTISED_PORT=9092

  kafkamirror:
    image: 'kafkamirror/kafkamirror'
    container_name: 'kafkamirror'
    networks:
      - kafka-net
    ports:
      - '3000:3000'
      - '8080:8080'
    depends_on:
      - spotify-kafka

With this configuration, I can spin up both containers, docker attach into the CLI, and ping each container from one another just fine. A docker network inspect kafka-simulator_kafka-net gives me the following:

[
    {
        "Name": "kafka-simulator_kafka-net",
        "Id": "a53e3972edc6c67bf6cfa6fdd1fc2c48796e9da1e8cabf0710cb1270eb53a1fe",
        "Created": "2021-01-07T02:42:32.744642052Z",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": null,
            "Config": [
                {
                    "Subnet": "172.29.0.0/16",
                    "Gateway": "172.29.0.1"
                }
            ]
        },
        "Internal": false,
        "Attachable": true,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {
            "10858507278d74479ca49b9f81c69f1ed71abbaf4915b17168cbce7797427153": {
                "Name": "spotify-kafka",
                "EndpointID": "acb8b94a73205a774aa15a491523ab91f40f5b7fc9e281dfebf6aaa024748035",
                "MacAddress": "02:42:ac:1d:00:02",
                "IPv4Address": "172.29.0.2/16",
                "IPv6Address": ""
            },
            "c478714194b4d4fea144e277c92952ff576feb37f16dbf831b0da148233cf371": {
                "Name": "kafkamirror",
                "EndpointID": "fe2be0eae705b4728c4153bc07e8d00f330dc7d24931590754416888c4efad26",
                "MacAddress": "02:42:ac:1d:00:03",
                "IPv4Address": "172.29.0.3/16",
                "IPv6Address": ""
            }
        },
        "Options": {},
        "Labels": {
            "com.docker.compose.network": "kafka-net",
            "com.docker.compose.project": "kafka-simulator",
            "com.docker.compose.version": "1.27.4"
        }
    }
]

The containers appear to be on the same network and can communicate with one another, however in my application code, I'm attempting to create a connection to Kafka using localhost:9092 which doesn't work once they're containerized, since they have different IP addresses. I've tried using the "host" driver with no luck.

Any ideas on how to establish a connection with Kafka once it's containerized? Is there a way to statically set the IP addresses or somehow retrieve the allocated IP address on startup with a docker command and set that within my application code? I'm just not sure what IP address to use within the code of my application.

Answer 1

等待大神答复