Want to deploy my application on multi-node kafka cluster, but not able to connect docker conatainers internally - apache-kafka

Question

---
version: '2'
services:
zookeeper-1:
image: confluentinc/cp-zookeeper:latest
environment:
ZOOKEEPER_SERVER_ID: 1
ZOOKEEPER_CLIENT_PORT: 22181
ZOOKEEPER_TICK_TIME: 2000
ZOOKEEPER_INIT_LIMIT: 5
ZOOKEEPER_SYNC_LIMIT: 2
ZOOKEEPER_SERVERS: localhost:22888:23888;localhost:32888:33888;localhost:42888:43888
network_mode: host
extra_hosts:
- "moby:127.0.0.1"
zookeeper-2:
image: confluentinc/cp-zookeeper:latest
environment:
ZOOKEEPER_SERVER_ID: 2
ZOOKEEPER_CLIENT_PORT: 32181
ZOOKEEPER_TICK_TIME: 2000
ZOOKEEPER_INIT_LIMIT: 5
ZOOKEEPER_SYNC_LIMIT: 2
ZOOKEEPER_SERVERS: localhost:22888:23888;localhost:32888:33888;localhost:42888:43888
network_mode: host
extra_hosts:
- "moby:127.0.0.1"
zookeeper-3:
image: confluentinc/cp-zookeeper:latest
environment:
ZOOKEEPER_SERVER_ID: 3
ZOOKEEPER_CLIENT_PORT: 42181
ZOOKEEPER_TICK_TIME: 2000
ZOOKEEPER_INIT_LIMIT: 5
ZOOKEEPER_SYNC_LIMIT: 2
ZOOKEEPER_SERVERS: localhost:22888:23888;localhost:32888:33888;localhost:42888:43888
network_mode: host
extra_hosts:
- "moby:127.0.0.1"
kafka-1:
image: confluentinc/cp-kafka:latest
network_mode: host
depends_on:
- zookeeper-1
- zookeeper-2
- zookeeper-3
environment:
KAFKA_BROKER_ID: 1
KAFKA_ZOOKEEPER_CONNECT: localhost:22181,localhost:32181,localhost:42181
KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://localhost:19092
extra_hosts:
- "moby:127.0.0.1"
kafka-2:
image: confluentinc/cp-kafka:latest
network_mode: host
depends_on:
- zookeeper-1
- zookeeper-2
- zookeeper-3
environment:
KAFKA_BROKER_ID: 2
KAFKA_ZOOKEEPER_CONNECT: localhost:22181,localhost:32181,localhost:42181
KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://localhost:29092
extra_hosts:
- "moby:127.0.0.1"
kafka-3:
image: confluentinc/cp-kafka:latest
network_mode: host
depends_on:
- zookeeper-1
- zookeeper-2
- zookeeper-3
environment:
KAFKA_BROKER_ID: 3
KAFKA_ZOOKEEPER_CONNECT: localhost:22181,localhost:32181,localhost:42181
KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://localhost:39092
extra_hosts:
- "moby:127.0.0.1"
this is the example from confluence for multi-node cluster, used network mode=host. what address should i use for internal connection.
for example the below one is single-node kafka cluster
kafka:
image: confluentinc/cp-kafka:latest
depends_on:
- zookeeper
ports:
- 9092:9092
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
here I can use kafka:29092 for internal connection.
i followed same approach for multi-node but getting error.
can anyone explain why this approach not work for multi-node cluster and how to establish internal connection.
thank you.

Answer 1

here I can use kafka:29092 for internal connection
That's because it was listed as an advertised listener for internal clients to connect to. KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://kafka:29092
You've removed the service name from each of your brokers, so clients are now trying to connect to just the advertised localhost addresses and failing because the containers running your applications are therefore trying to connect to themselves (via localhost), not any of the kafka containers.