Confluent Schema Registry unable to connect to Kafka container - apache-kafka

Question

I'm trying to run a Kafka service with Zookeper, Kafdrop and Schema Registry, I made it work by installing Kafka, Zookeper and Kadrop in a container and then installing Confluent Schema Registry in another (with its own Kafka, Zookeeper, Ksql Server and Rest Proxy), however trying to make kafdrop read the schema registry is not working, so now I want to install exclusively just one container with Kafka, Zookeeper, Kafdrop and Schema Registry, and even though everything is installed successfully, the Schema Registry is restarting every 10 seconds or so, and I cannot reach out the service (localhost:8085) to add my schema, so I'm wondering if it's even possible to run the Confluent Schema Registry outside the Confluent suite of services, here it is my YAML file:
version: '2'
services:
kafka:
image: wurstmeister/kafka
container_name: kafka
ports:
- "9092:9092"
environment:
- KAFKA_ADVERTISED_HOST_NAME=127.0.0.1
- KAFKA_ADVERTISED_PORT=9092
- KAFKA_ZOOKEEPER_CONNECT=zookeeper:2181
- KAFKA_LISTENERS=INTERNAL://:29092,EXTERNAL://:9092
- KAFKA_ADVERTISED_LISTENERS=INTERNAL://kafka:29092,EXTERNAL://localhost:9092
- KAFKA_LISTENER_SECURITY_PROTOCOL_MAP=INTERNAL:PLAINTEXT,EXTERNAL:PLAINTEXT
- KAFKA_INTER_BROKER_LISTENER_NAME=INTERNAL
- KAFKA_SCHEMA_REGISTRY_URL=schemaregistry:8085
depends_on:
- zookeeper
zookeeper:
image: wurstmeister/zookeeper
container_name: zookeeper
ports:
- "2181:2181"
environment:
- KAFKA_ADVERTISED_HOST_NAME=zookeeper
schemaregistry:
image: confluentinc/cp-schema-registry:6.2.0
restart: always
depends_on:
- zookeeper
environment:
SCHEMA_REGISTRY_KAFKASTORE_CONNECTION_URL: "zookeeper:2181"
SCHEMA_REGISTRY_HOST_NAME: schemaregistry
SCHEMA_REGISTRY_LISTENERS: "http://0.0.0.0:8085"
ports:
- 8085:8085
kafdrop:
image: obsidiandynamics/kafdrop
container_name: kafdrop
restart: "no"
ports:
- "9000:9000"
environment:
KAFKA_BROKERCONNECT: "kafka:29092"
JVM_OPTS: "-Xms16M -Xmx48M -Xss180K -XX:-TieredCompilation -XX:+UseStringDeduplication -noverify"
SCHEMAREGISTRY_CONNECT: schemaregistry:8085
depends_on:
- "kafka"

Answer 1

So it turned out that the Schema Registry couldn't connect because Kafka was not using 'PLAINTEXT' as the internal broker listener name, here is the YAML version working with the Kafdrop also working when deserializing the message to AVRO:
version: '2'
services:
kafka:
image: wurstmeister/kafka
container_name: kafka
ports:
- "9092:9092"
environment:
- KAFKA_ADVERTISED_HOST_NAME=127.0.0.1
- KAFKA_ADVERTISED_PORT=9092
- KAFKA_ZOOKEEPER_CONNECT=zookeeper:2181
- KAFKA_LISTENERS=PLAINTEXT://:29092,EXTERNAL://:9092
- KAFKA_ADVERTISED_LISTENERS=PLAINTEXT://kafka:29092,EXTERNAL://localhost:9092
- KAFKA_LISTENER_SECURITY_PROTOCOL_MAP=PLAINTEXT:PLAINTEXT,EXTERNAL:PLAINTEXT
- KAFKA_INTER_BROKER_LISTENER_NAME=PLAINTEXT
- KAFKA_SCHEMA_REGISTRY_URL=schemaregistry:8085
depends_on:
- zookeeper
zookeeper:
image: wurstmeister/zookeeper
container_name: zookeeper
ports:
- "2181:2181"
environment:
- KAFKA_ADVERTISED_HOST_NAME=zookeeper
schemaregistry:
image: confluentinc/cp-schema-registry:6.2.0
restart: always
depends_on:
- zookeeper
environment:
SCHEMA_REGISTRY_KAFKASTORE_CONNECTION_URL: "zookeeper:2181"
SCHEMA_REGISTRY_HOST_NAME: schemaregistry
SCHEMA_REGISTRY_LISTENERS: "http://0.0.0.0:8085"
ports:
- 8085:8085
kafdrop:
image: obsidiandynamics/kafdrop
container_name: kafdrop
restart: "no"
ports:
- "9000:9000"
environment:
KAFKA_BROKERCONNECT: "kafka:29092"
JVM_OPTS: "-Xms16M -Xmx48M -Xss180K -XX:-TieredCompilation -XX:+UseStringDeduplication -noverify"
SCHEMAREGISTRY_CONNECT: http://schemaregistry:8085
depends_on:
- "kafka"

Answer 2

Your both YAML are not correct
You have in zookeeper:
KAFKA_ADVERTISED_HOST_NAME
And in schema registry you give zookeeper port 2181 in kafkastore....