docker-compose.yml

services:
  # Controller
  kafka_controller:
    image: confluentinc/cp-kafka:latest
    environment:
      # General Configs
      ## Role in the cluster.
      KAFKA_PROCESS_ROLES: controller 
      ## Must be unique within the cluster.
      KAFKA_NODE_ID: 101
      ## Votes for himself, as there are no more controllers.
      KAFKA_CONTROLLER_QUORUM_VOTERS: 101@kafka_controller:8000 
      ## Must be unique across all clusters sharing the same environment.
      CLUSTER_ID: cluster-id
      KAFKA_LOG_DIRS: ./controller-logs

      # Networking
      ## Comma separated list of <listener name>:<protocol> pairs. We'll always use plaintext for the sake of simplicity.
      KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: CONTROLLER:PLAINTEXT
      ## Network interfaces and ports for which the controllers accepts incoming connections.
      KAFKA_LISTENERS: CONTROLLER://0.0.0.0:8000
      ## Defines the listener used by for inter-controller and broker-controller communications.
      KAFKA_CONTROLLER_LISTENER_NAMES: CONTROLLER
    networks:
      ## Getting everything on the same network.
      - kafka_network
    ports:
      ## Controller's port.
      - "8000:8000"

  # Broker
  kafka_broker:
    image: confluentinc/cp-kafka:latest
    environment:
      # General Configs
      ## Role in the cluster.
      KAFKA_PROCESS_ROLES: broker
      ## Must be unique within the cluster.
      KAFKA_NODE_ID: 1
      ## Points to the only controller defined above, as there are no more controllers.
      KAFKA_CONTROLLER_QUORUM_VOTERS: 101@kafka_controller:8000
      ## This is 3 by default, but since we're running on a single broker, can only have 1.
      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
      ## Must be unique across all clusters sharing the same environment.
      CLUSTER_ID: cluster-id
      KAFKA_LOG_DIRS: ./kafka-data

      # Networking
      ## Network interfaces and ports for which the broker accepts incoming connections.
      KAFKA_LISTENERS: EXTERNAL://kafka_broker:9092,INTERNAL://0.0.0.0:9093
      ## Network interfaces and ports for which the broker accepts external connections.
      ## i.e., this defines what the clients connect to.
      ## I personally disagree with how this config is named and explained because,
      ## in order to define a KAFKA_INTER_BROKER_LISTENER_NAME, you need to add it to KAFKA_ADVERTISED_LISTENERS.
      KAFKA_ADVERTISED_LISTENERS: EXTERNAL://kafka_broker:9092,INTERNAL://kafka_broker:9093
      ## Comma separated list of <listener name>:<protocol> pairs. We'll always use plaintext for the sake of simplicity.
      KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: INTERNAL:PLAINTEXT,EXTERNAL:PLAINTEXT,CONTROLLER:PLAINTEXT
      ## Defines the listener used by for inter-controller and broker-controller communications.
      KAFKA_CONTROLLER_LISTENER_NAMES: CONTROLLER
      ## Defines the listener use for inter-broker communication.
      KAFKA_INTER_BROKER_LISTENER_NAME: INTERNAL
    ports:
      ## Broker's ports.
      - "9092:9092"
      - "9093:9093"
    networks:
      ## Getting everything on the same network.
      - kafka_network
    depends_on:
      - kafka_controller

  # Client
  kafka_client:
    build:
      context: .
      dockerfile: Dockerfile
    container_name: kafka_client
    environment:
      ## Point to your Kafka broker in the Docker network
      KAFKA_BROKER: kafka_broker:9092 
    networks:
      ## Getting everything on the same network.
      - kafka_network  
    stdin_open: true
    tty: true
    depends_on:
      ## Ensure the broker is up before running the client
      - kafka_broker  

networks:
  kafka_network:
    driver: bridge