Docker部署Confluent Kafka Schema Registry：PLAINTEXT端点未找到报错求助

报错信息 #

java.lang.RuntimeException: No endpoints found for security protocol [PLAINTEXT]. Endpoints found in ZK [{INTERNAL=kafka:9092, OUTSIDE=localhost:29092}]

我的Schema Registry配置 #

schema-registry:
  image: confluentinc/cp-schema-registry:7.3.2
  environment:
    - SCHEMA_REGISTRY_KAFKASTORE_CONNECTION_URL=zookeeper:2181
    - SCHEMA_REGISTRY_HOST_NAME=schema-registry
    - ALLOW_PLAINTEXT_LISTENER='yes'
    - SCHEMA_REGISTRY_LISTENERS=http://schema-registry:8081
    - SCHEMA_REGISTRY_KAFKASTORE_BOOTSTRAP_SERVERS=PLAINTEXT://kafka:29092
  links:
    - zookeeper
    - kafka
  ports:
    - 8082:8081

完整Docker Compose配置 #

zookeeper:
    image: confluentinc/cp-zookeeper:6.2.4
    healthcheck:
      test: [ "CMD", "nc", "-vz", "localhost", "2181" ]
      interval: 10s
      timeout: 3s
      retries: 3
    environment:
      ZOOKEEPER_CLIENT_PORT: 2181
      ZOOKEEPER_TICK_TIME: 2000
    ports:
      - 22181:2181

kafka:
    image: confluentinc/cp-kafka:6.2.4
    depends_on:
      zookeeper:
        condition: service_healthy
    ports:
      - 29092:29092
    healthcheck:
      test: [ "CMD", "nc", "-vz", "localhost", "9092" ]
      interval: 10s
      timeout: 3s
      retries: 3
    environment:
      KAFKA_BROKER_ID: 1
      KAFKA_ZOOKEEPER_CONNECT: zookeeper:2181
      KAFKA_LISTENERS: OUTSIDE://:29092,INTERNAL://:9092
      KAFKA_ADVERTISED_LISTENERS: OUTSIDE://localhost:29092,INTERNAL://kafka:9092
      KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: INTERNAL:PLAINTEXT,OUTSIDE:PLAINTEXT
      KAFKA_INTER_BROKER_LISTENER_NAME: INTERNAL
      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1

kafka-ui:
    image: provectuslabs/kafka-ui
    container_name: kafka-ui
    ports:
      - "8080:8080"
    restart: always
    depends_on:
      kafka:
        condition: service_healthy
    environment:
      KAFKA_CLUSTERS_0_NAME: local
      KAFKA_CLUSTERS_0_BOOTSTRAPSERVERS: kafka:9092

service-db:
    image: postgres:14.7-alpine
    environment:
      POSTGRES_USER: username
      POSTGRES_PASSWORD: password
    healthcheck:
      test: ["CMD-SHELL", "pg_isready", "-d", "clients_database"]
      interval: 10s
      timeout: 3s
      retries: 3
    ports:
      - "15432:5432"
    volumes:
      - ./infrastructure/db/create_db.sql:/docker-entrypoint-initdb.d/create_db.sql
    restart: unless-stopped

pgadmin:
    container_name: pgadmin_container
    image: dpage/pgadmin4:7
    restart: always
    environment:
      PGADMIN_DEFAULT_EMAIL: admin@admin.com
      PGADMIN_DEFAULT_PASSWORD: root
    ports:
      - "5050:80"

schema-registry:
    image: confluentinc/cp-schema-registry:7.3.2
    environment:
      - SCHEMA_REGISTRY_KAFKASTORE_CONNECTION_URL=zookeeper:2181
      - SCHEMA_REGISTRY_HOST_NAME=schema-registry
      - ALLOW_PLAINTEXT_LISTENER='yes'
      - SCHEMA_REGISTRY_LISTENERS=http://schema-registry:8081
      - SCHEMA_REGISTRY_KAFKASTORE_BOOTSTRAP_SERVERS=PLAINTEXT://kafka:29092
    links:
      - zookeeper
      - kafka
    ports:
      - 8082:8081

kafka-topics-generator:
    image: confluentinc/cp-kafka:6.2.4
    depends_on:
      kafka:
        condition: service_healthy
    entrypoint: [ '/bin/sh', '-c' ]
    command: |
        "
        # blocks until kafka is reachable
        kafka-topics --bootstrap-server kafka:9092 --list
        
        echo -e 'Creating kafka topics'
        kafka-topics --bootstrap-server kafka:9092 --create --if-not-exists --topic send-order-event --replication-factor 1 --partitions 2
        
        echo -e 'Successfully created the following topics:'
        kafka-topics --bootstrap-server kafka:9092 --list
        "

解决方案 #

报错根源是Schema Registry配置的SCHEMA_REGISTRY_KAFKASTORE_BOOTSTRAP_SERVERS使用了kafka:29092，但该端口对应Kafka的OUTSIDE监听器，其对外暴露地址为localhost:29092，Docker内部容器通信应使用Kafka的INTERNAL监听器地址kafka:9092。

同时注意ALLOW_PLAINTEXT_LISTENER无需添加单引号，修正后的Schema Registry配置如下：

schema-registry:
  image: confluentinc/cp-schema-registry:7.3.2
  environment:
    - SCHEMA_REGISTRY_KAFKASTORE_CONNECTION_URL=zookeeper:2181
    - SCHEMA_REGISTRY_HOST_NAME=schema-registry
    - ALLOW_PLAINTEXT_LISTENER=yes
    - SCHEMA_REGISTRY_LISTENERS=http://schema-registry:8081
    - SCHEMA_REGISTRY_KAFKASTORE_BOOTSTRAP_SERVERS=PLAINTEXT://kafka:9092
  links:
    - zookeeper
    - kafka
  ports:
    - 8082:8081

内容的提问来源于stack exchange，提问作者Irina