Kafka Docker network_mode

Question

I'm trying to get Kafka up and running on my Mac using docker compose.

This is my docker-compose.yml file:

version: '2'
services:
zookeeper:
   image: ********
   network_mode: "host"
   hostname: "zookeeper"
   environment:
     - "MYID=1"
   ports:
     - "2181:2181"
     - "3888:3888"
mysql:
   image: *******
   network_mode: "host"
   hostname: "mysql"
   environment:
     - "MYSQL_ROOT_PASSWORD=password"
   ports:
     - "3306:3306"
schema-registry:
   image: ********
   network_mode: "host"
   hostname: "schema-registry"
   environment:
     - "ZOOKEEPER_URL=127.0.0.1:2181"
   ports:
     - "8081:8081"
kafka:
   image: **********
   network_mode: "host"
   hostname: "kafka"
   environment:
     - "SERVICE_NAME=localhost"
     - "SERVICE_TAGS=syracuse-dev"
     - "KAFKA_ADVERTISED_HOST_NAME=localhost"
     - "KAFKA_ZOOKEEPER_CONNECT=localhost:2181"
     - "KAFKA_NUM_PARTITIONS=10"
     - "KAFKA_LISTENERS=PLAINTEXT://:9092"
     - "KAFKA_BROKER_ID=1"
     - "KAFKA_DEFAULT_REPLICATION_FACTOR=1"
   ports:
     - "9092:9092"
     - "7203:7203"

Everything gets up and running with the exception of Kafka. As Kafka loads it looks for Zookeeper once found I receive the following error.

Found zookeeper
Error: Exception thrown by the agent : java.net.MalformedURLException: Local host name unknown: java.net.UnknownHostException: moby: moby: unknown error

I was able to get Kafka up and running by removing the "network_mode: "host" lines from each container. And setting the zookeeper url to: "zookeeper:2181"

It's unclear to me what the network_mode does and why it impeded kafka from running. I'm hoping someone can shed some light onto this and educate me.

much appreciated

ferdy ferdy · Accepted Answer · 2016-09-07T18:49:32

You may instead of

- "KAFKA_ADVERTISED_HOST_NAME=localhost"
- "KAFKA_ZOOKEEPER_CONNECT=localhost:2181"

provide them with the name of the zookeeper container, which is zookeeper in your case.

- "KAFKA_ADVERTISED_HOST_NAME=zookeeper"
- "KAFKA_ZOOKEEPER_CONNECT=zookeper:2181"

Does that help?

Kafka Docker network_mode

1 Answers