Confluent Confluent Certifications CCDAK Questions & Answers

• Question 101:

  A Zookeeper ensemble contains 5 servers. What is the maximum number of servers that can go missing and the ensemble still run?

  A. 3

  B. 4

  C. 2

  D. 1

  Correct Answer: C

  majority consists of 3 zk nodes for 5 nodes zk cluster, so 2 can fail

• Question 102:

  If I want to send binary data through the REST proxy, it needs to be base64 encoded. Which component needs to encode the binary data into base 64?

  A. The Producer

  B. The Kafka Broker

  C. Zookeeper

  D. The REST Proxy

  Correct Answer: A

  The REST Proxy requires to receive data over REST that is already base64 encoded, hence it is the responsibility of the producer

• Question 103:

  You are receiving orders from different customer in an "orders" topic with multiple partitions. Each message has the customer name as the key. There is a special customer named ABC that generates a lot of orders and you would like to

  reserve a partition exclusively for ABC. The rest of the message should be distributed among other partitions.

  How can this be achieved?

  A. Add metadata to the producer record

  B. Create a custom partitioner

  C. All messages with the same key will go the same partition, but the same partition may have messages with different keys. It is not possible to reserve

  D. Define a Kafka Broker routing rule

  Correct Answer: B

  A Custom Partitioner allows you to easily customise how the partition number gets computed from a source message.

• Question 104:

  A consumer starts and has auto.offset.reset=latest, and the topic partition currently has data for offsets going from 45 to 2311. The consumer group has committed the offset 643 for the topic before. Where will the consumer read from?

  A. it will crash

  B. offset 2311

  C. offset 643

  D. offset 45

  Correct Answer: C

  The offsets are already committed for this consumer group and topic partition, so the property auto.offset.reset is ignored

• Question 105:

  In Avro, removing or adding a field that has a default is a __ schema evolution

  A. full

  B. backward

  C. breaking

  D. forward

  Correct Answer: A

  Clients with new schema will be able to read records saved with old schema and clients with old schema will be able to read records saved with new schema.

• Question 106:

  You have a consumer group of 12 consumers and when a consumer gets killed by the process management system, rather abruptly, it does not trigger a graceful shutdown of your consumer. Therefore, it takes up to 10 seconds for a rebalance to happen. The business would like to have a 3 seconds rebalance time. What should you do? (select two)

  A. Increase session.timeout.ms

  B. Decrease session.timeout.ms

  C. Increase heartbeat.interval.ms

  D. decrease max.poll.interval.ms

  E. increase max.poll.interval.ms

  F. Decrease heartbeat.interval.ms

  Correct Answer: BF

  session.timeout.ms must be decreased to 3 seconds to allow for a faster rebalance, and the heartbeat thread must be quicker, so we also need to decrease heartbeat.interval.ms

• Question 107:

  In the Kafka consumer metrics it is observed that fetch-rate is very high and each fetch is small. What steps will you take to increase throughput?

  A. Increase fetch.max.wait

  B. Increase fetch.max.bytes

  C. Decrease fetch.max.bytes

  D. Decrease fetch.min.bytes

  E. Increase fetch.min.bytes

  Correct Answer: E

  This will allow consumers to wait and receive more bytes in each fetch request.

• Question 108:

  A consumer application is using KafkaAvroDeserializer to deserialize Avro messages. What happens if message schema is not present in AvroDeserializer local cache?

  A. Throws SerializationException

  B. Fails silently

  C. Throws DeserializationException

  D. Fetches schema from Schema Registry

  Correct Answer: D

  First local cache is checked for the message schema. In case of cache miss, schema is pulled from the schema registry. An exception will be thrown in the Schema Registry does not have the schema (which should never happen if you set it up properly)

• Question 109:

  You have a Kafka cluster and all the topics have a replication factor of 3. One intern at your company stopped a broker, and accidentally deleted all the data of that broker on the disk. What will happen if the broker is restarted?

  A. The broker will start, and other topics will also be deleted as the broker data on the disk got deleted

  B. The broker will start, and won't be online until all the data it needs to have is replicated from other leaders

  C. The broker will crash

  D. The broker will start, and won't have any data. If the broker comes leader, we have a data loss

  Correct Answer: B

  Kafka replication mechanism makes it resilient to the scenarios where the broker lose data on disk, but can recover from replicating from other brokers. This makes Kafka amazing!

• Question 110:

  A kafka topic has a replication factor of 3 and min.insync.replicas setting of 1. What is the maximum number of brokers that can be down so that a producer with acks=all can still produce to the topic?

  A. 3

  B. 0

  C. 2

  D. 1

  Correct Answer: C

  Two brokers can go down, and one replica will still be able to receive and serve data