无法连接到本地 Docker 容器中的单个 Kafka 代理

Question

我正在使用 Wurstmeister Docker Image 尝试运行一个非常基本的单一代理 Kafka 服务器用于测试我的应用程序。

这是一个简单的docker-compose.yml：

version: '2'
services:
  zookeeper:
    image: wurstmeister/zookeeper
    ports:
      - '2181:2181'
  kafka:
    image: wurstmeister/kafka
    ports:
      - '9092:9092'
    environment:
      KAFKA_ADVERTISED_HOST_NAME: localhost
      KAFKA_ADVERTISED_PORT: 9092
      KAFKA_ZOOKEEPER_CONNECT: zookeeper:2181
      KAFKA_AUTO_CREATE_TOPICS_ENABLE: 'true'
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock

我可以进入容器，并使用标准二进制文件创建主题，例如

> docker exec -it ${container} kafka-topics.sh --create --topic my-topic --bootstrap-server localhost:9092
> docker exec -it ${container} kafka-topics.sh --list --bootstrap-server localhost:9092
my-topic

显示容器信息显示暴露的端口9092：

> docker ps
CONTAINER ID   IMAGE                      COMMAND                  CREATED          STATUS         PORTS                                                NAMES
14b0210787cf   wurstmeister/zookeeper     "/bin/sh -c '/usr/sb…"   11 seconds ago   Up 9 seconds   22/tcp, 2888/tcp, 3888/tcp, 0.0.0.0:2181->2181/tcp   catalog-ingestor-service_zookeeper_1
9ecb59c1bfdd   wurstmeister/kafka         "start-kafka.sh"         11 seconds ago   Up 9 seconds   0.0.0.0:9092->9092/tcp                               catalog-ingestor-service_kafka_1

使用kcat (kafkacat)，我使用自制程序安装，我尝试连接并收到错误：

> kcat -b localhost:9092 -L
%3|1645810235.301|FAIL|rdkafka#producer-1| [thrd:localhost:9092/bootstrap]: localhost:9092/bootstrap: Failed to resolve 'localhost:9092': nodename nor servname provided, or not known (after 5002ms in state CONNECT)
% ERROR: Failed to acquire metadata: Local: Broker transport failure (Are the brokers reachable? Also try increasing the metadata timeout with -m <timeout>?)

我很确定我应该尝试在 localhost:9092 上连接，但即使当我 ping 时它似乎没有解决：

> ping localhost:9092
ping: cannot resolve localhost:9092: Unknown host

另外，我假设我不需要在 Kafka Broker 和 Zookeeper 之间显式创建网络/桥，因为 zookeeper:2181 已经解析了该桥？

Answer 1

那么，使用端口 ping 不会帮助检查您是否可以到达端口。

不管怎样，我在 Confluence Kafka 上遇到了类似的问题，我必须明确公开端口。请参阅以下 yaml：

---
version: '2'
services:
  zookeeper:
    image: confluentinc/cp-zookeeper:6.2.0
    container_name: zookeeper
    restart: always
    expose:
      - '2181'
    environment:
      ZOOKEEPER_SERVER_ID: 1
      ZOOKEEPER_CLIENT_PORT: 2181
      ZOOKEEPER_TICK_TIME: 2000
      ZOOKEEPER_INIT_LIMIT: 5
      ZOOKEEPER_SYNC_LIMIT: 2
      ZOOKEEPER_SERVERS: 0.0.0.0:2888:3888
      ZOOKEEPER_MAX_CLIENT_CNXNS: 0
    volumes:
      - /Users/pacone/broker/zookeeper-logs/data:/var/lib/zookeeper/data
      - /Users/pacone/broker/zookeeper-logs/log:/var/lib/zookeeper/log

  kafka-one:
    image: confluentinc/cp-kafka:6.2.0
    container_name: kafka-one
    restart: always
    expose: 
      - '9092'
    depends_on:
      - zookeeper
    ports:
      - '9092:9092'
      - '29092:29092'

environment:
  KAFKA_BROKER_ID: 10
  KAFKA_ZOOKEEPER_CONNECT: zookeeper:2181
  KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: INTERNAL:PLAINTEXT,EXTERNAL:PLAINTEXT
  KAFKA_ADVERTISED_LISTENERS: INTERNAL://kafka-one:29092,EXTERNAL://localhost:9092
  KAFKA_INTER_BROKER_LISTENER_NAME: INTERNAL
  KAFKA_DEFAULT_REPLICATION_FACTOR: 1
  KAFKA_NUM_PARTITIONS: 1
  KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
  KAFKA_TRANSACTION_STATE_LOG_REPLICATION_FACTOR: 1
  KAFKA_TRANSACTION_STATE_LOG_MIN_ISR: 1
  KAFKA_ZOOKEEPER_CONNECTION_TIMEOUT_MS: 6000
volumes:
  - /Users/yourUsername/broker/kafka-logs/data:/var/lib/kafka/data

使用之前的配置，我可以从 Java 连接：

干杯

Answer 2

您可以检查 9092 端口是否被任何其他进程使用吗？如果是，那么尝试改变它。
另外，尝试使 docker-compose 版本为 3