Unable to connect Schema Registry to existing kafka setup [duplicate] - docker

Question

I'm running ksqldb-server from a docker-compor found here https://ksqldb.io/quickstart.html#quickstart-content
My kafka bootstrap server is running on the same VM in standard alone mode.
I can see the messages in one topic with a console consumer:
sudo kafka-avro-console-consumer --from-beginning --bootstrap-server localhost:9092 --topic source-air-input --property print.key=true --max-messages 2
Unfortunatly running ksql from docker gives me this error.
ksqldb-server | [2021-07-15 23:12:58,772] ERROR Failed to start KSQL (io.confluent.ksql.rest.server.KsqlServerMain:66)
ksqldb-server | java.lang.RuntimeException: Failed to get Kafka cluster information
ksqldb-server | at io.confluent.ksql.services.KafkaClusterUtil.getKafkaClusterId(KafkaClusterUtil.java:107)
ksqldb-server | at io.confluent.ksql.rest.server.KsqlRestApplication.buildApplication(KsqlRestApplication.java:624)
ksqldb-server | at io.confluent.ksql.rest.server.KsqlServerMain.createExecutable(KsqlServerMain.java:152)
ksqldb-server | at io.confluent.ksql.rest.server.KsqlServerMain.main(KsqlServerMain.java:59)
ksqldb-server | Caused by: java.util.concurrent.TimeoutException
ksqldb-server | at org.apache.kafka.common.internals.KafkaFutureImpl$SingleWaiter.await(KafkaFutureImpl.java:108)
ksqldb-server | at org.apache.kafka.common.internals.KafkaFutureImpl.get(KafkaFutureImpl.java:272)
ksqldb-server | at io.confluent.ksql.services.KafkaClusterUtil.getKafkaClusterId(KafkaClusterUtil.java:105)
My docker-compose.yml is the following.
---
version: '3.9'
services:
ksqldb-server:
image: confluentinc/ksqldb-server:0.18.0
hostname: ksqldb-server
container_name: ksqldb-server
extra_hosts:
- "host.docker.internal:host-gateway"
ports:
- "8088:8088"
environment:
KSQL_LISTENERS: http://0.0.0.0:8088
KSQL_BOOTSTRAP_SERVERS: host.docker.internal:9092
KSQL_KSQL_LOGGING_PROCESSING_STREAM_AUTO_CREATE: "true"
KSQL_KSQL_LOGGING_PROCESSING_TOPIC_AUTO_CREATE: "true"
ksqldb-cli:
image: confluentinc/ksqldb-cli:0.18.0
container_name: ksqldb-cli
depends_on:
- ksqldb-server
entrypoint: /bin/sh
tty: true
I tried many possible configurations for the address without success.
What might be wrong?
I tried the suggestions from this question From inside of a Docker container, how do I connect to the localhost of the machine? without success.

Answer 1

Modify Kafka's server.properties
listener.security.protocol.map=PLAINTEXT_DOCKER:PLAINTEXT,PLAINTEXT_LOCAL:PLAINTEXT
listeners=PLAINTEXT_DOCKER://:29092,PLAINTEXT_LOCAL://localhost:9092
advertised.listeners=PLAINTEXT_DOCKER://host.docker.internal:29092,PLAINTEXT_LOCAL://localhost:9092
inter.broker.listener.name=PLAINTEXT_LOCAL
Update your Compose like so to point at the host rather than itself
version: '3.9'
services:
# TODO: add schema-registry
# environment:
# SCHEMA_REGISTRY_KAFKASTORE_BOOTSTRAP_SERVERS: host.docker.internal:29092
# extra_hosts:
# - "host.docker.internal:host-gateway"
# or any other Kafka client
ksqldb-server:
image: confluentinc/ksqldb-server:0.18.0
hostname: ksqldb-server
container_name: ksqldb-server
ports:
- "8088:8088"
extra_hosts:
- "host.docker.internal:host-gateway"
environment:
KSQL_BOOTSTRAP_SERVERS: host.docker.internal:29092
...
(Tested on Mac), Getting /info endpoint of KSQL
http :8088/info
HTTP/1.1 200 OK
content-length: 133
content-type: application/json
{
"KsqlServerInfo": {
"kafkaClusterId": "ZH2-h1W_SaivCW0qa8DQGA",
"ksqlServiceId": "default_",
"serverStatus": "RUNNING",
"version": "0.18.0"
}
}
Replace all host.docker.internal above with the external hostname/IP of the machine, if Kafka is a remote server