How to Prepare for the Confluent Certified Operator for Apache Kafka (CCOAK) exam

Stéphane Maarek
4 min readMay 16, 2020

Getting the Apache Kafka certification from Confluent is a great way of making sure to have your skills recognized by your current and future employees. But how do you prepare for that certification?


I personally find the CCOAK certification of medium difficulty, and if you have seriously used Apache Kafka in the past year, many questions shouldn’t be surprising. Nonetheless, it is best to be as prepared as you can, as the certification cost of 150 USD is not something you’d rather pay for twice.

I have created a practice exam course with 2 practice tests of 40 questions each… so 80 sample questions. Check it out here (discount coupon included!). Completing those is a great first step to assess where you stand today. Additionally, I recommend checking out the sample questions from confluent at You will find three sample questions in this blog, read on!

Please also read the CCOAK certification FAQ at

Exam Details

Studying for the Certification

If you find lacking the knowledge, you may already know I have plenty of online content with the Apache Kafka Series to help you learn Kafka at your own pace and with over 35 hours of videos. A countless number of my students did successfully pass the CCOAK certification exam after studying with my online courses.

Let’s deep dive into what you need to know for each exam topic:

Apache Kafka Fundamentals

You need to know everything about brokers, topics, partitions, offsets, producers and message keys, consumers and consumer groups, delivery semantics, Zookeeper, and more. My Apache Kafka for Beginners course will help you get there

Kafka Setup

You’ll need to know the kinks of setting up a Kafka cluster, important configurations, and so on. Check out my Kafka Setup course

Kafka Security

Understanding some of the intricate details of Kafka Security will be helpful for your exam to address 2–3 questions. Check out my Kafka Security course

Kafka Monitoring & Operations

Knowledge in these areas is key to pass the exam — it’s a Certified Confluent Operator exam after all. Check out my Kafka Monitoring & Operations course.

Other knowledge

  • Kafka Streams, KSQL, Kafka Connect should be known at a high level
  • same goes for Confluent components at a high level: Confluent Schema Registry, Confluent REST Proxy, Confluent Replicator, Confluent Control Centre.
  • If you’re interested in these in a deep dive, here’s a link to all my Kafka courses

Sample questions

The following questions are an extract of my Practice Exam course (responses at the bottom of the blog):

Q1: You have created a Producer but some messages have failed to be sent to Kafka on the first try. You have now included the setting `retries=5` and after careful analysis of your topic, you have seen that sometimes duplicates are sent by the producer. How can you solve that issue?

  • A: Set `enable.idempotence=true`
  • B: Set `retries=Integer.MAX_VALUE`
  • C: Set `retries=0`
  • D: Enable compression

Q2: A consumer inside a group is reading messages from Kafka. After doing `.poll(long)`, the consumer processes an unusually large batch of messages that got stuck on it for a long time. The consumer is then disconnected from the group. Which setting did trigger this behavior?

  • A: ``
  • B: ``
  • C: `max.poll.records`

Q3: What happens if you send a message to Kafka that does not contain any partition key?

  • A: The Kafka broker will refuse the message
  • B: The message will be sent as is to a random partition
  • C: The Kafka client will generate a random partition key and assign it to the message
  • D: The Kafka broker will generate a random partition key and assign it to the message

Closing Comments

Don’t rush your certification, especially if you’re just getting started with Apache Kafka, as I find the exam really great at testing your actual experience using Apache Kafka. Take your time to learn and practice, and answering the questions will seem natural.

If I have helped you get the certification, leave a comment here or a review on my Udemy course!

Happy learning and I wish you good luck with the CCOAK certification!

Quiz answers: 1A, 2B, 3B

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