gistfile1.txt

version: '2'
services:
  zookeeper:
    image: "confluentinc/cp-zookeeper:4.1.0"
    ports:
     - "2181:2181"
    expose:
     - "2181"
    environment:
     - ZOOKEEPER_CLIENT_PORT=2181
  kafka:
    image: "confluentinc/cp-kafka:4.1.0"
    hostname: kafka
    links:
     - zookeeper
    ports:
     - "9092:9092"
    expose:
     - "9092"
    environment:
     - KAFKA_ZOOKEEPER_CONNECT=localhost:2181
     - KAFKA_ADVERTISED_LISTENERS=PLAINTEXT://localhost:9092
     - KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR=1

I think the issue is localhost meaning the container's loopback instead of the host's loopback. I've used the host's IP address instead of localhost with some success.

You can refer to zookeeper using the hostname zookeeper when using docker-compose

How you connect to the instances from your machine depends on what you're using for docker.

docker-machine runs docker inside a VM so you have to use the VMs IP which you can find by running docker-machine env

IIRC docker for Mac allows you to use localhost, I'd assume docker for Windows can as well.