1.报错情况：

52059 [main] WARN  o.a.k.c.NetworkClient - [Consumer clientId=zy_client_id, groupId=consumer] Connection to node 3 (/172.20.0.22:9093) could not be established. Broker may not be available.
110300 [main] WARN  o.a.k.c.NetworkClient - [Consumer clientId=zy_client_id, groupId=consumer] Connection to node 3 (/172.20.0.22:9093) could not be established. Broker may not be available.
131434 [main] WARN  o.a.k.c.NetworkClient - [Consumer clientId=zy_client_id, groupId=consumer] Connection to node 2 (/172.20.0.21:9092) could not be established. Broker may not be available.
152602 [main] WARN  o.a.k.c.NetworkClient - [Consumer clientId=zy_client_id, groupId=consumer] Connection to node 4 (/172.20.0.23:9094) could not be established. Broker may not be available.
173746 [main] WARN  o.a.k.c.NetworkClient - [Consumer clientId=zy_client_id, groupId=consumer] Connection to node 3 (/172.20.0.22:9093) could not be established. Broker may not be available.
194905 [main] WARN  o.a.k.c.NetworkClient - [Consumer clientId=zy_client_id, groupId=consumer] Connection to node 2 (/172.20.0.21:9092) could not be established. Broker may not be available.
216041 [main] WARN  o.a.k.c.NetworkClient - [Consumer clientId=zy_client_id, groupId=consumer] Connection to node 4 (/172.20.0.23:9094) could not be established. Broker may not be available.

 2.问题解决：

在IDEA上连接kafka集群失败，一般是配置文件出错可以检查你的docker.yml配置文件。

# 报错时仅配置了
listeners=PLAINTEXT://IP:9092

# 处理后
listeners=PLAINTEXT://云服务器IP:9092
advertised.listeners=PLAINTEXT://云服务器外网IP:9092

附上我的配置文件相关部分：

kafka1:
    image: 'bitnami/kafka:latest'
    restart: always    
    container_name: kafka1
    hostname: kafka1
    ports:
      - '9092:9092'
    environment:
      - ALLOW_NONE_AUTHENTICATION=yes
      - ALLOW_PLAINTEXT_LISTENER=yes 
      - KAFKA_BROKER_ID=1
      - KAFKA_CFG_LISTENERS=PLAINTEXT://0.0.0.0:9092
      - KAFKA_CFG_ADVERTISED_LISTENERS=PLAINTEXT://kafka1:9092
      - KAFKA_CFG_ZOOKEEPER_CONNECT=z1:2181,z2:2181,z3:2181
    volumes:
      - /D/docker_desktop/k1/kafka1:/bitnami/kafka      
    networks:
      - zk-net

  kafka2:
    image: 'bitnami/kafka:latest'
    restart: always       
    container_name: kafka2
    hostname: kafka2
    ports:
      - '9093:9093'
    environment:
      - ALLOW_NONE_AUTHENTICATION=yes
      - ALLOW_PLAINTEXT_LISTENER=yes 
      - KAFKA_BROKER_ID=2
      - KAFKA_CFG_LISTENERS=PLAINTEXT://0.0.0.0:9093
      - KAFKA_CFG_ADVERTISED_LISTENERS=PLAINTEXT://kafka2:9093
      - KAFKA_CFG_ZOOKEEPER_CONNECT=z1:2181,z2:2181,z3:2181
    volumes:
      - /D/docker_desktop/k1/kafka2:/bitnami/kafka        
    networks:
      - zk-net

  kafka3:
    image: 'bitnami/kafka:latest'
    restart: always       
    container_name: kafka3
    hostname: kafka3
    ports:
      - '9094:9094'
    environment:
      - ALLOW_NONE_AUTHENTICATION=yes
      - ALLOW_PLAINTEXT_LISTENER=yes 
      - KAFKA_BROKER_ID=3
      - KAFKA_CFG_LISTENERS=PLAINTEXT://0.0.0.0:9094    
      - KAFKA_CFG_ADVERTISED_LISTENERS=PLAINTEXT://kafka3:9094
      - KAFKA_CFG_ZOOKEEPER_CONNECT=z1:2181,z2:2181,z3:2181
    volumes:
      - /D/docker_desktop/k1/kafka3:/bitnami/kafka    
    networks:
      - zk-net

如果还没成功，请检查一下C:\Windows\System32\drivers\etc路径下的hosts文件，是否将kafka的网络添加进去，不然idea无法识别，这是idea机制问题。

如若还未成功，请寻找其他方法。