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?

Drusie

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.

Lucknow

That might have done the trick, but isn't the idea of a Docker Compose that this trick (to add the hostname to /etc/hosts on the Docker host) should not be necessary because it is solved in the Docker network? (Most likely by adding the right hostnames of the composition to the /etc/hosts files in the running containers.) – Chimera

Editing the hosts file is a hack. Refer rmoff.net/2018/08/02/kafka-listeners-explained – Locution

Answer 2

Assuming that this is a setup intended for your local development environment, here is a solution for running in a Docker network.

version: '2'

services:
  zookeeper:
    image: confluentinc/cp-zookeeper:3.2.0
    environment:
      ZOOKEEPER_CLIENT_PORT: 2181
      ZOOKEEPER_TICK_TIME: 2000
    restart: always
    ports: ['2181:2181']

  kafka:
    image: confluentinc/cp-kafka:3.2.0
    depends_on:
    - zookeeper
    ports: ['29092:29092']
    environment:
      KAFKA_BROKER_ID: 1
      KAFKA_ZOOKEEPER_CONNECT: zookeeper:2181
      KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://kafka:29092,PLAINTEXT_HOST://localhost:9092
      KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: PLAINTEXT:PLAINTEXT,PLAINTEXT_HOST:PLAINTEXT
      KAFKA_INTER_BROKER_LISTENER_NAME: PLAINTEXT
      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
    restart: always

  kafka-rest:
    image: confluentinc/cp-kafka-rest:3.2.0
    depends_on:
    - kafka
    ports: ['8082:8082']
    environment:
      KAFKA_REST_ZOOKEEPER_CONNECT: 'zookeeper:2181'
      KAFKA_REST_LISTENERS: http://0.0.0.0:8082
      KAFKA_REST_SCHEMA_REGISTRY_URL: http://schema-registry:8081
      KAFKA_REST_HOST_NAME: localhost
    restart: always

  schema-registry:
    image: confluentinc/cp-schema-registry:3.2.0
    depends_on:
    - kafka        
    ports: ['8081:8081']
    environment:
      SCHEMA_REGISTRY_KAFKASTORE_CONNECTION_URL: 'zookeeper:2181'
      SCHEMA_REGISTRY_HOST_NAME: schema-registry
      SCHEMA_REGISTRY_LISTENERS: http://0.0.0.0:8081
    restart: always

  connect:
    image: confluentinc/cp-kafka-connect:3.2.0
    depends_on:
    - zookeeper
    - kafka
    - schema-registry
    ports: ['8083:8083']
    restart: always
    environment:
      CONNECT_BOOTSTRAP_SERVERS: 'kafka:29092'
      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"

Updated here - https://github.com/confluentinc/examples/blob/5.3.1-post/cp-all-in-one/docker-compose.yml

Sardinian

No! Don't edit the hosts file. It works fine on Mac (and windows) if you configure the environment variables correctly rmoff.net/2018/08/02/kafka-listeners-explained – Locution

Answer 3

Single Kafka with single Zookepper

version: '2.1'

services:
    zookeeper:
      image: wurstmeister/zookeeper
      hostname: zookeeper
      container_name: zookeeper
      ports:
        - "2181:2181"
      environment:
          ZOO_MY_ID: 1
          ZOO_PORT: 2181
          ZOO_SERVERS: server.1=zookeeper:2888:3888
          restart: always
      volumes:
        - ./zk-single-kafka-single/zookeeper/data:/data
        - ./zk-single-kafka-single/zookeeper/datalog:/datalog

    kafka:
       image: wurstmeister/kafka
       hostname: kafka
       container_name: kafka
       ports:
         - "9092:9092"
       environment:
         HOSTNAME_COMMAND: "docker info | grep ^Name: | cut -d' ' -f 2"
         KAFKA_ADVERTISED_LISTENERS: LISTENER_DOCKER_INTERNAL://kafka:9092,LISTENER_DOCKER_EXTERNAL://_{HOSTNAME_COMMAND}:9094
         KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: LISTENER_DOCKER_INTERNAL:PLAINTEXT,LISTENER_DOCKER_EXTERNAL:PLAINTEXT
         KAFKA_ZOOKEEPER_CONNECT: "zookeeper:2181"
         KAFKA_LISTENERS: LISTENER_DOCKER_INTERNAL://:9092,LISTENER_DOCKER_EXTERNAL://:9094
         KAFKA_INTER_BROKER_LISTENER_NAME: LISTENER_DOCKER_INTERNAL
         KAFKA_ADVERTISED_HOST_NAME: 172.19.0.1
         KAFKA_BROKER_ID: 1
         KAFKA_LOG4J_LOGGERS: "kafka.controller=INFO,kafka.producer.async.DefaultEventHandler=INFO,state.change.logger=INFO"
         KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
         restart: always
       volumes:
         - ./zk-single-kafka-single/kafka/data:/var/lib/kafka/data
       depends_on:
         - zookeeper

Samhita