Exam Review - Prometheus Certified Associate

Last week I sat, and passed, the Prometheus Certified Associate exam. The certification from the Linux Foundation is testing foundational knowledge in observability in general and Prometheus in particular.

"A certified PCA will confirm foundational knowledge for building or scraping observability data in the application stack whether or not it is cloud native" ~ From the Linux Foundation website

Preparations and resources

I've worked with Prometheus for quite some time, although not all the functionality and the most complex queries, but I had a solid base and with this I passed the exam without issues

Certificate Handbook

Certifications from the Linux Foundation follow a set of common procedures and guidelines. This can be found in the Certificate Handbook. Although there's not much specific to the PCA exam in this, it gives general guidelines and tips for the Linux Foundation exams delivered through the PCI platform.

Testing environment

The PCI proctoring platform delivers an online "ExamUI" which is used for the multiple choice exams which the PCA exam is. The UI is quite easy to understand and I had no issues with it. There is an option to run a test on before-hand which let's you familiarize yourself with the environment. Note that this is available after you schedule the exam and it's available only up until 2 hours prior to the real exam.

The testing environment, i.e. the physical environment, has some requirements. Overall this sums up to the fact that the physical environment should not contain anything that might help, or even give the impression of helping, the candidate in passing the exam. Meaning no one but the candidate in the room, the room must be quiet and private, clear desk from all notes and other electronics.

During the check in you will need to use your camera to document the room live.

Curriculum and training

The objectives tested for the exam is the following

Domain	Weight
Observability Concepts	18%
Prometheus Fundamentals	20%
PromQL	28%
Instrumentation and Exporters	16%
Alerting & Dashboarding	18%

Preparing for this exam, especially if you're new to Prometheus, I would obviously focus on the Prometheus fundamentals and PromQL. This weighs in at nearly 50% of the exam.

More details on the curriculum can be found here

When you buy the PCA exam there's an option of adding the LFS241 training course which I believe will prepare you well enough for the remaining objectives.

For PromQL in particular I believe you should familiarize even more and work on different types of queries, both more generic queries on individual metrics and different set of queries where combining multiple metrics and/or different types of functions. Make sure you understand what kind of metrics the different operators and functions work with, and how to use them. Aggregations over time and dimensions as well as Histograms is also something you need to be proficient in.

A good place to start would be the Prometheus documentation

Also make sure you understand the different components that makes up Prometheus and the eco-system, and how they're used and tied together, e.g. the exporters, Alertmanager and dashboarding. There will be questions on Prometheus configuration so make sure you also understand where to configure different options (alerting, recording, scrape config, etc).

There will also be general questions on observability concepts, and also instrumentation of apps, so a basic understanding of this is also needed.

The exam

The exam it self was a straight forward multiple choice exam. I had 60 questions and I scored 93%, well within the passing score of 75%.

You'll have 90 minutes for the exam, for me this was more than enough. I usually flag a few questions for review, and I had plenty of time to review them and finished the exam in around 60 minutes.

A general tip on the questions is to always read the question properly and see that you understand what they're actually asking for. Also review all alternatives, normally one or two might be easy to discard, leaving only two or three to choose from. This helps a lot when and if your'e not 100% sure of the answer to the question.

I did the exam on my laptop on a MacBook Air with a 13" display which was sufficient for a good ExamUI experience since this is a multiple choice exam only.

The result was not presented directly after ending the exam, but I got an email shortly after with the result. It's also visible in the Exam Preparation checklist in the Linux Foundation training portal.

Summary

All in all I would say for a candidate with experience with Prometheus, even in a simple lab environment, configuring the different options, scrape configs and with some experience on the basic exporters like Node Exporter and Blackbox, will be able to pass this exam with a little preparation.

For me the only real challenge was some of the PromQL questions where you needed to remember when and what aggregation and/or function to use. Not all functions are available (or at least makes sense) on all types of metric types.

Hopefully this post can help prepare for the Prometheus Certified Associate exam. Thanks for reading and feel free to reach out if you have any questions or comments