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This article will explain in detail what common interview questions there are in Kafka. The editor thinks it is very practical, so I share it for you as a reference. I hope you can get something after reading this article.

1. What is Apache Kafka?

Apache Kafka is a publish / subscribe messaging system developed by Apache. It is a distributed, partitioned and repetitive logging service.

2. Please explain what is the traditional method of messaging?

There are two traditional messaging methods:

Queuing: in a queue, a group of users can read messages from the server, and each message is sent to one of them.

Publish-subscribe: in this model, messages are broadcast to all users.

3. What are the advantages of Kafka over traditional technologies?

The advantages of Apache Kafka over traditional messaging technologies are:

Fast: a single Kafka agent can handle thousands of clients, handling megabytes of read and write operations per second.

Scalable: partitioning and simplifying data on a set of machines to support larger data

Persistence: messages are persistent and replicated in the cluster to prevent data loss.

Design: it provides fault tolerance and persistence

4. What is the meaning of broker in Kafka?

In a Kafka cluster, the broker term is used to reference a server.

5. What is the maximum information that the Kafka server can receive?

The maximum message size that can be received by the Kafka server is 1000000 bytes.

6. Explain what is the Zookeeper of Kafka? Can we use Kafka without Zookeeper?

Zookeeper is an open source, high-performance coordination service for distributed applications of Kafka.

No, it's impossible to get past Zookeeper and contact Kafka broker directly. Once Zookeeper stops working, it cannot serve client requests.

Zookeeper is mainly used to communicate between different nodes in a cluster.

In Kafka, it is used to commit offsets, so if the node fails in any case, it can be obtained from the previously submitted offset.

In addition, it performs other activities, such as leader detection, distributed synchronization, configuration management, identifying when new nodes leave or connect, clustering, node real-time status, and so on.

7. Explain how Kafka users consume information?

Passing messages in Kafka is done by using sendfile API. It supports transferring bytes from sockets to disk, saving copies through kernel space, and calling the kernel between kernel users.

Explain how to improve the throughput of remote users.

If the user is in a different data center than broker, you may need to tune the socket buffer size to amortize long network delays.

9. Explain how you can get accurate information from Kafka in the data production process.

In data, in order to get Kafka messages accurately, you must follow two things: avoid repetition during data consumption and avoid repetition during data production.

There are two ways to accurately obtain a semantics during data generation:

Each partition uses a separate writer, and whenever you find a network error, check the last message in the partition to see if your last write was successful.

Include a primary key (UUID or other) in the message and reverse copy it in the user

10. Explain how to reduce the disturbance in ISR? when does broker leave ISR?

ISR is a set of message copies that are fully synchronized with leaders, which means that ISR contains all submitted messages. ISR should always contain all copies until a real failure occurs. If a copy is detached from leader, it will be deleted from ISR.

11. Why does Kafka need to be copied?

Kafka's information replication ensures that any published messages are not lost and can be used in machine errors, program errors, or more common software upgrades.

12. What does it mean if the copy stays in ISR for a long time?

If a copy is kept in ISR for a long time, it indicates that the tracker cannot get data as quickly as it collects data in leader.

13. Please explain what will happen if the preferred copy is not in ISR?

If the preferred copy is not in ISR, the controller will not be able to transfer the leadership to the preferred copy.

14. Is it possible to have a message offset after production?

In most queuing systems, a class as a producer cannot do this, and its role is to trigger and forget messages. Broker will do the rest of the work, such as using id for appropriate metadata processing, offsets, and so on.

As a user of the message, you can get compensation from Kafka broker. If you look at the SimpleConsumer class, you will notice that it gets the MultiFetchResponse object that includes the offset as a list. In addition, when you iterate over Kafka messages, you will have MessageAndOffset objects that include offsets and message delivery.

This is the end of the article on "what are the common interview questions in Kafka". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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