在Kafka节点中创建主题分区

Question

const myProducerStream = ({ kafkaHost, highWaterMark, topic }) => {
    const kafkaClient = new KafkaClient({ kafkaHost });
    const producer = new HighLevelProducer(kafkaClient);
    const options = {
        highWaterMark,
        kafkaClient,
        producer
    }; 

    kafkaClient.refreshMetadata([topic], err => {
        if (err) throw err; 
    }); 

    return new ProducerStream(options);
};

const transfrom = topic => new Transform({
    objectMode: true,
    decodeStrings: true,
    transform(obj, encoding, cb) {
        console.log(`pushing message ${JSON.stringify(obj)} to topic "${topic}"`);

        cb(null, {
            topic,
            messages: JSON.stringify(obj)
        });
    }
});

const publisher = (topic, kafkaHost, highWaterMark) => {
    const myTransfrom = transfrom(topic);
    const producer = myProducerStream({ kafkaHost, highWaterMark, topic });

    myTransfrom.pipe(producer);

    return myTransform;
};

const createConsumerStream = (sourceTopic, kafkaHost, groupId) => {
    const consumerOptions = {
        kafkaHost,
        groupId,
        protocol: ['roundrobin'],
        encoding: 'utf8',
        id: uuidv4(),
        fromOffset: 'latest',
        outOfRangeOffset: 'earliest',
    };

    const consumerGroupStream = new ConsumerGroupStream(consumerOptions, sourceTopic);

    consumerGroupStream.on('connect', () => {
        console.log(`Consumer id: "${consumerOptions.id}" is connected!`);
    });

    consumerGroupStream.on('error', (err) => {
        console.error(`Consumer id: "${consumerOptions.id}" encountered an error: ${err}`);
    });

    return consumerGroupStream; 
};

const publisher = (func, destTopic, consumerGroupStream, kafkaHost, highWaterMark) => { 
    const messageTransform = new AsyncMessageTransform(func, destTopic);

    const resultProducerStream = myProducerStream({ kafkaHost, highWaterMark, topic: destTopic })

    consumerGroupStream.pipe(messageTransform).pipe(resultProducerStream);
}; 

Answer 1

对于第一个问题：一个组中最大的工作使用者等于分区的数量。

因此，如果您有一个分区的TopicA，而您的消费者组中有5个消费者，其中4个将是空闲的。

如果您有5个分区的TopicA，并且您的消费者组中有5个消费者，那么他们都将是活跃的，并且消费来自您的主题的消息。

bin/kafka-topics.sh --create --bootstrap-server localhost:9092 --replication-factor 3 --partitions 3 --topic test

要更改已存在主题中的分区数,请执行以下操作：

bin/kafka-topics.sh --zookeeper zk_host:port/chroot --alter --topic test 
       --partitions 40 

请注意，只能增加分区数，不能减少分区数。

请参阅Kafka Docs https://Kafka.apache.org/documentation.html

此外，如果您想了解更多关于Kafaka的信息，请查阅免费书籍https://www.confluent.io/resources/kafka-the-definitive-guide/