CCDAK Confluent Certified Developer for Apache Kafka Certification Examination Questions and Answers

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

Preferred leader is a broker that was leader when topic was created. It is preferred because when partitions are first created, the leaders are balanced between brokers. Otherwise, any of the in-sync replicas (ISR) will be elected leader, as long as unclean.leader.election=false (by default)

This is active-passing as the replicated topic is used for read-only purposes only

The Controller is a broker that is responsible for electing partition leaders

Sending a message with the null value is called a tombstone in Kafka and will ensure the log compacted topic does not contain any messages with the key K upon compaction

linger.ms forces the producer to wait to send messages, hence increasing the chance of creating batches

min.insync.replicas does not impact producers when acks=1 (only when acks=all)

In Kafka, a small heap size is needed, while the rest of the RAM goes automatically to the page cache (managed by the OS). The heap size goes slightly up if you need to enable SSL

You will need to set the schemas.enable parameters for the converter to false for plain text with no schema.

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

Default port of KSQL server is 8088

SpecificRecord is created from generated record classes

Multiple topics can be passed as a list or regex pattern.

Your Zookeeper cluster needs to have an odd number of servers, and must maintain a majority of servers up to be able to vote. Therefore, a 2N+1 zookeeper cluster can survive to N zookeeper being down, so here the right answer is N=2, 2*N+1=5

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

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)

Controller is a broker that in addition to usual broker functions is responsible for partition leader election. The election of that broker happens thanks to Zookeeper and at any time only one broker can be a controller

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.

Partitions for newly created topics are assigned in a rack alternating manner, this is the only change broker.rack does