KCNA Cloud Native Observability Practice Question
Which Prometheus metric type is best suited to count the number of HTTP requests received?
⚠ Common exam trap
KCNA often tests the misconception that Histogram or Summary is needed for request counting because they also expose a _count — candidates overlook that Counter is the purpose-built type for monotonically increasing totals.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Counter
A Counter is a Prometheus metric type that represents a cumulative value that only increases (or resets to zero on restart). It is the correct choice for counting total HTTP requests received because the value monotonically increases over time. PromQL's rate() and increase() functions are designed to work with counters to compute per-second rates.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Gauge
Why it's wrong here
A gauge records values that rise and fall, so it cannot accumulate a running total of requests without manual resets. It suits current in-flight requests or queue depth. Counting demands a monotonically increasing counter, which Prometheus exposes via the counter type.
- ✗
Histogram
Why it's wrong here
A histogram buckets observations and produces a sum and count, aimed at latency or size distributions. It does track a count, but the stem asks which type counts requests, and the counter is the dedicated type for that. Histograms suit response-time percentiles.
- ✗
Summary
Why it's wrong here
A Summary records observations and calculates client-side quantiles over a sliding window, which is unnecessary overhead for a simple tally. A Counter is the correct type for monotonically increasing totals such as HTTP requests, queried with rate() or increase().
- ✓
Counter
Why this is correct
Counters are monotonically increasing metrics that only go up or reset to zero on restart, making them ideal for cumulative counts such as total HTTP requests received. Use rate() or increase() to derive per-second request rates from the counter.
About these practice questions
This KCNA question is part of Courseiva's 930-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 more way this is tested on KCNA
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. What type of Prometheus metric is best suited to count the total number of HTTP requests received by a service?
medium- A.Histogram
- B.Gauge
- C.Summary
- ✓ D.Counter
Why D: A Counter is a cumulative metric that only increases (or resets to zero on restart), making it ideal for tracking the total number of events like HTTP requests. Since the total request count is monotonically increasing, a Counter directly represents this without additional processing. Other metric types like Gauge, Histogram, and Summary serve different purposes: Gauge can go up and down, Histogram and Summary are for distributions (e.g., request durations).
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CNCF exam blueprint
This KCNA practice question is part of Courseiva's free CNCF certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the KCNA exam.