Kafka setup with docker-compose

Question

Hi I'm currently setting up Kafka with Docker. I've managed to setup Zookeeper and Kafka with the published confluent image, see following docker-compose file:

version: '2'

services:
  zookeeper:
    image: confluentinc/cp-zookeeper:3.2.0
    container_name: zookeeper
    hostname: zookeeper
    ports:
      - "2181:2181"
    environment:
      ZOOKEEPER_CLIENT_PORT: 2181
      ZOOKEEPER_TICK_TIME: 2000
    restart: always

  kafka:
    image: confluentinc/cp-kafka:3.2.0
    hostname: kafka
    container_name: kafka
    depends_on:
      - zookeeper
    ports:
      - '9092:9092'
    environment:
      KAFKA_BROKER_ID: 1
      KAFKA_ZOOKEEPER_CONNECT: 'zookeeper:2181'
      KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://192.168.99.100:9092
      LISTENERS: PLAINTEXT://0.0.0.0:9092
    restart: always

  kafka-rest:
   image: confluentinc/cp-kafka-rest:3.2.0
   container_name: kafka-rest
   depends_on:
     - kafka
   ports:
     - '8082:8082'
   environment:
     KAFKA_REST_ZOOKEEPER_CONNECT: 'zookeeper:2181'
     KAFKA_REST_LISTENERS: http://kafka-rest:8082
     KAFKA_REST_SCHEMA_REGISTRY_URL: http://schema-registry:8081
     KAFKA_REST_HOST_NAME: kafka-rest
   restart: always

 schema-registry:
   image: confluentinc/cp-schema-registry:3.2.0
   container_name: schema-registry
   depends_on:
     - kafka
   ports:
     - '8081'
   environment:
     SCHEMA_REGISTRY_KAFKASTORE_CONNECTION_URL: 'zookeeper:2181'
     SCHEMA_REGISTRY_HOST_NAME: schema-registry
     SCHEMA_REGISTRY_LISTENERS: http://schema-registry:8081
   restart: always

 connect:
   image: confluentinc/cp-kafka-connect:3.2.0
   container_name: kafka-connect
   depends_on:
     - zookeeper
     - kafka
     - schema-registry
   ports:
     - "8083:8083"
   restart: always
   environment:
     CONNECT_BOOTSTRAP_SERVERS: 'kafka:9092'
     CONNECT_REST_ADVERTISED_HOST_NAME: connect
     CONNECT_REST_PORT: 8083
     CONNECT_GROUP_ID: compose-connect-group
     CONNECT_CONFIG_STORAGE_TOPIC: docker-connect-configs
     CONNECT_OFFSET_STORAGE_TOPIC: docker-connect-offsets
     CONNECT_STATUS_STORAGE_TOPIC: docker-connect-status
     CONNECT_KEY_CONVERTER: io.confluent.connect.avro.AvroConverter
     CONNECT_KEY_CONVERTER_SCHEMA_REGISTRY_URL: http://schema-registry:8081
     CONNECT_VALUE_CONVERTER: io.confluent.connect.avro.AvroConverter
     CONNECT_VALUE_CONVERTER_SCHEMA_REGISTRY_URL: http://schema-registry:8081
     CONNECT_INTERNAL_KEY_CONVERTER: org.apache.kafka.connect.json.JsonConverter
     CONNECT_INTERNAL_VALUE_CONVERTER: org.apache.kafka.connect.json.JsonConverter
     CONNECT_ZOOKEEPER_CONNECT: "zookeeper:2181"

Now I've managed to expose correctly the Kafka container to my non-dockerized applications by correctly setting the advertised.listener property to PLAINTEXT://{DOCKER_MACHINE_IP}:9092, but as you can see I've also added other confluent applications to extend my Kafka setup (Kafka REST, Schema-Registry). These can no longer connect to my Kafka instance because of the advertised.listener property.

I could change it to the correct container hostname --> PLAINTEXT://kafka:9092 but then I lose the ability to reach the kafka instance once again with my other apps. Is there any easy way to solve this issue?

Answer 1

Omar, maybe you've already resolved your problem, but for future reference, Hans Jespersen's comment did the trick for me, even on Windows.

As admin, open C:\Windows\System32\drivers\etc\hosts and add the following line to expose the kafka broker as localhost. 127.0.0.1 broker

And mydocker-compose.yml file looks as follows:

---
version: '2'
services:
  zookeeper:
    image: confluentinc/cp-zookeeper
    hostname: zookeeper
    extra_hosts:
    - "moby:127.0.0.1"
    ports:
      - "2181:2181"
    environment:
      ZOOKEEPER_CLIENT_PORT: 2181
      ZOOKEEPER_TICK_TIME: 2000

  broker:
    image: confluentinc/cp-kafka
    hostname: broker
    extra_hosts:
    - "moby:127.0.0.1"
    depends_on:
      - zookeeper
    ports:
      - '9092:9092'
    environment:
      KAFKA_BROKER_ID: 1
      KAFKA_ZOOKEEPER_CONNECT: 'zookeeper:2181'
      KAFKA_ADVERTISED_LISTENERS: 'PLAINTEXT://broker:9092'
      KAFKA_DEFAULT_REPLICATION_FACTOR: 1

  schema_registry:
    image: confluentinc/cp-schema-registry
    hostname: schema_registry
    # extra_hosts:
    # - "moby:127.0.0.1"
    depends_on:
      - zookeeper
      - broker
    ports:
      - '8081:8081'
    environment:
      SCHEMA_REGISTRY_HOST_NAME: schema_registry
      SCHEMA_REGISTRY_KAFKASTORE_CONNECTION_URL: 'zookeeper:2181'

  kafka-rest:
    image: confluentinc/cp-kafka-rest
    container_name: kafka-rest
    extra_hosts:
    - "moby:127.0.0.1"
    depends_on:
      - zookeeper
      - broker
    ports:
      - '8082:8082'
    environment:
      KAFKA_REST_ZOOKEEPER_CONNECT: 'zookeeper:2181'
      KAFKA_REST_LISTENERS: http://kafka-rest:8082
      KAFKA_REST_SCHEMA_REGISTRY_URL: http://schema-registry:8081
      KAFKA_REST_HOST_NAME: kafka-rest

Alternatively, exposing my laptop's current IP address (using ipconfig /all) works too, but this has the disadvantage that, whenever my network changes, I would have to change the docker-compose.yml file too.