CCDAK Exam - Confluent Certified Developer for Apache Kafka Certification Examination

NEW QUESTION 1
Where are KSQL-related data and metadata stored?

• A. Kafka Topics
• B. Zookeeper
• C. PostgreSQL database
• D. Schema Registry

Answer: A

Explanation:
metadata is stored in and built from the KSQL command topic. Each KSQL server has its own in-memory version of the metastore.

NEW QUESTION 2
You are sending messages with keys to a topic. To increase throughput, you decide to
increase the number of partitions of the topic. Select all that apply.

• A. All the existing records will get rebalanced among the partitions to balance load
• B. New records with the same key will get written to the partition where old records with that key were written
• C. New records may get written to a different partition
• D. Old records will stay in their partitions

Answer: CD

Explanation:
Increasing the number of partition causes new messages keys to get hashed differently, and breaks the guarantee "same keys goes to the same partition". Kafka logs are immutable and the previous messages are not re-shuffled

NEW QUESTION 3
You are doing complex calculations using a machine learning framework on records fetched from a Kafka topic. It takes more about 6 minutes to process a record batch, and the consumer enters rebalances even though it's still running. How can you improve this scenario?

• A. Increase max.poll.interval.ms to 600000
• B. Increase heartbeat.interval.ms to 600000
• C. Increase session.timeout.ms to 600000
• D. Add consumers to the consumer group and kill them right away

Answer: A

Explanation:
Here, we need to change the setting max.poll.interval.ms (default 300000) to its double in order to tell Kafka a consumer should be considered dead if the consumer only if it hasn't called the .poll() method in 10 minutes instead of 5.

NEW QUESTION 4
Which Kafka CLI should you use to consume from a topic?

• A. kafka-console-consumer
• B. kafka-topics
• C. kafka-console
• D. kafka-consumer-groups

Answer: A

Explanation:
Examplekafka-console-consumer --bootstrap-server 127.0.0.1:9092 --topic test --from- beginning

NEW QUESTION 5
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

Answer: C

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

NEW QUESTION 6
An ecommerce wesbite sells some custom made goods. What's the natural way of modeling this data in Kafka streams?

• A. Purchase as stream, Product as stream, Customer as stream
• B. Purchase as stream, Product as table, Customer as table
• C. Purchase as table, Product as table, Customer as table
• D. Purchase as stream, Product as table, Customer as stream

Answer: B

Explanation:
Mostly-static data is modeled as a table whereas business transactions should be modeled as a stream.

NEW QUESTION 7
When using the Confluent Kafka Distribution, where does the schema registry reside?

• A. As a separate JVM component
• B. As an in-memory plugin on your Zookeeper cluster
• C. As an in-memory plugin on your Kafka Brokers
• D. As an in-memory plugin on your Kafka Connect Workers

Answer: A

Explanation:
Schema registry is a separate application that provides RESTful interface for storing and retrieving Avro schemas.

NEW QUESTION 8
A Zookeeper configuration has tickTime of 2000, initLimit of 20 and syncLimit of 5. What's the timeout value for followers to connect to Zookeeper?

• A. 20 sec
• B. 10 sec
• C. 2000 ms
• D. 40 sec

Answer: D

Explanation:
tick time is 2000 ms, and initLimit is the config taken into account when establishing a connection to Zookeeper, so the answer is 2000 * 20 = 40000 ms = 40s

NEW QUESTION 9
You want to send a message of size 3 MB to a topic with default message size configuration. How does KafkaProducer handle large messages?

• A. KafkaProducer divides messages into sizes of max.request.size and sends them in order
• B. KafkaProducer divides messages into sizes of message.max.bytes and sends them in order
• C. MessageSizeTooLarge exception will be thrown, KafkaProducer will not retry and return exception immediately
• D. MessageSizeTooLarge exception will be thrown, KafkaProducer retries until the number of retries are exhausted

Answer: C

Explanation:
MessageSizeTooLarge is not a retryable exception.

NEW QUESTION 10
If I produce to a topic that does not exist, and the broker setting auto.create.topic.enable=true, what will happen?

• A. Kafka will automatically create the topic with 1 partition and 1 replication factor
• B. Kafka will automatically create the topic with the indicated producer settings num.partitions and default.replication.factor
• C. Kafka will automatically create the topic with the broker settings num.partitions and default.replication.factor
• D. Kafka will automatically create the topic with num.partitions=#of brokers and replication.factor=3

Answer: C

Explanation:
The broker settings comes into play when a topic is auto created

NEW QUESTION 11
What are the requirements for a Kafka broker to connect to a Zookeeper ensemble? (select two)

• A. Unique value for each broker's zookeeper.connect parameter
• B. Unique values for each broker's broker.id parameter
• C. All the brokers must share the same broker.id
• D. All the brokers must share the same zookeeper.connect parameter

Answer: BD

Explanation:
Each broker must have a unique broker id and connect to the same zk ensemble and root zNode

NEW QUESTION 12
You want to sink data from a Kafka topic to S3 using Kafka Connect. There are 10 brokers in the cluster, the topic has 2 partitions with replication factor of 3. How many tasks will you configure for the S3 connector?

• A. 10
• B. 6
• C. 3
• D. 2

Answer: D

Explanation:
You cannot have more sink tasks (= consumers) than the number of partitions, so 2.

NEW QUESTION 13
Which actions will trigger partition rebalance for a consumer group? (select three)

• A. Increase partitions of a topic
• B. Remove a broker from the cluster
• C. Add a new consumer to consumer group
• D. A consumer in a consumer group shuts down Add a broker to the cluster

Answer: ACD

Explanation:
Rebalance occurs when a new consumer is added, removed or consumer dies or paritions increased.

NEW QUESTION 14
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

Answer: D

Explanation:
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)

NEW QUESTION 15
Which of the following is true regarding thread safety in the Java Kafka Clients?

• A. One Producer can be safely used in multiple threads
• B. One Consumer can be safely used in multiple threads
• C. One Consumer needs to run in one thread
• D. One Producer needs to be run in one thread

Answer: AC

Explanation:
KafkaConsumer is not thread-safe, KafkaProducer is thread safe.

NEW QUESTION 16
A consumer starts and has auto.offset.reset=none, and the topic partition currently has data for offsets going from 45 to 2311. The consumer group has committed the offset 10 for the topic before. Where will the consumer read from?

• A. offset 45
• B. offset 10
• C. it will crash
• D. offset 2311

Answer: C

Explanation:
auto.offset.reset=none means that the consumer will crash if the offsets it's recovering from have been deleted from Kafka, which is the case here, as 10 < 45

NEW QUESTION 17
A producer just sent a message to the leader broker for a topic partition. The producer used acks=1 and therefore the data has not yet been replicated to followers. Under which conditions will the consumer see the message?

• A. Right away
• B. When the message has been fully replicated to all replicas
• C. Never, the produce request will fail
• D. When the high watermark has advanced

Answer: D

Explanation:
The high watermark is an advanced Kafka concept, and is advanced once all the ISR replicates the latest offsets. A consumer can only read up to the value of the High Watermark (which can be less than the highest offset, in the case of acks=1)

NEW QUESTION 18
The exactly once guarantee in the Kafka Streams is for which flow of data?

• A. Kafka => Kafka
• B. Kafka => External
• C. External => Kafka

Answer: A

Explanation:
Kafka Streams can only guarantee exactly once processing if you have a Kafka to Kafka topology.

NEW QUESTION 19
Your manager would like to have topic availability over consistency. Which setting do you need to change in order to enable that?

• A. compression.type
• B. unclean.leader.election.enable
• C. min.insync.replicas

Answer: B

Explanation:
unclean.leader.election.enable=true allows non ISR replicas to become leader, ensuring availability but losing consistency as data loss will occur

NEW QUESTION 20
Kafka is configured with following parameters - log.retention.hours = 168 log.retention.minutes = 168 log.retention.ms = 168 How long will the messages be retained for?

• A. Broker will not start due to bad configuration
• B. 168 ms
• C. 168 hours
• D. 168 minutes

Answer: B

Explanation:
If more than one similar config is specified, the smaller unit size will take precedence.

NEW QUESTION 21
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