Shulou(Shulou.com)05/31 Report--

This article mainly explains "what is the function of kafka under Docker". Interested friends may wish to have a look at it. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn "what is the function of kafka under Docker"?

Kafka is a high-throughput distributed publish and subscribe messaging system. From this chapter, we first experience it as fast as possible, then build a kafka environment under docker, and finally develop a java web application to experience kafka services.

Create a new docker-compose.yml file with the following contents:

Version: '2'services: zk_server: image: daocloud.io/library/zookeeper:3.3.6 restart: always kafka_server: image: bolingcavalry/kafka:0.0.1 links:-zk_server:zkhost command: / bin/sh-c' / usr/local/work/start_server.sh' restart: always message_producer: image: bolingcavalry/kafka:0.0.1 links:-zk_ Server:zkhost-kafka_server:kafkahost restart: always message_consumer: image: bolingcavalry/kafka:0.0.1 links:-zk_server:zkhost restart: always

Open the terminal and execute docker-compose up-d in the directory where the docker-compose.yml resides. Since you need to download the image from hub.docker.com, you need to wait a few minutes. After the download, four containers will be launched automatically, as shown below:

In order to better observe the effect, we need to open three terminals to operate on different containers. Later, we use numbers to express different terminals, and the numbers correspond to the following:

No. 1: kafka server 2: message producer (producer) 3: message consumer (consumer)

Enter the following command in Terminal 1 to see the real-time output information of kafka server:

Docker logs-f dockerkafka_kafka_server_1

The information you see after entering the command is as shown below. The connection to zookeeper is successful and the startup is successful:

Enter the following command in Terminal 2 to enter the message producer container:

Docker exec-it dockerkafka_message_producer_1 / bin/bash

Then execute the following command to create a theme:

WORK_PATH/$KAFKA_PACKAGE_NAME/bin/kafka-topics.sh-- create-- zookeeper zkhost:2181-- replication-factor 1-- partitions 1-- topic test001

Enter the following command in Terminal 3 to enter the message consumer container:

Docker exec-it dockerkafka_message_consumer_1 / bin/bash

Execute the following command to view all topics on the current kafka sever:

$WORK_PATH/$KAFKA_PACKAGE_NAME/bin/kafka-topics.sh-list-zookeeper zkhost:2181

You can see the theme you just created at Terminal 2, as shown below:

Continue to execute the following command on Terminal 3 to subscribe to messages with the topic test001:

$WORK_PATH/$KAFKA_PACKAGE_NAME/bin/kafka-console-consumer.sh-zookeeper zkhost:2181-topic test001-from-beginning

When you return to Terminal 1, you can see the connection information of the message subscriber container, as shown below:

Now that the topic has been created and subscriptions added, you can test the sending and receiving of messages:

At Terminal 2, execute the following command to enter the interactive mode of sending messages:

$WORK_PATH/$KAFKA_PACKAGE_NAME/bin/kafka-console-producer.sh-broker-list kafkahost:9092-topic test001

Now that you have entered interactive mode, continue to enter a string, such as hello Worldwide, and enter the enter key to send the content as "hello world!" As shown in the following figure:

Now when you go back to Terminal 3, you can see that the latest message has been received and the content has been printed, as shown below:

Finally, when we return to Terminal 1, we can see the connection information of the message producer, as shown below:

At this point, I believe you have a deeper understanding of "what is the function of kafka under Docker". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.