PCA Promql Practice Question
Which function would you use to find the maximum value of a gauge metric 'node_cpu_load' over the past 30 minutes?
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
✓
max_over_time(node_cpu_load[30m])
The max_over_time() function calculates the maximum value of all data points in the specified range vector for each time series.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
rate(node_cpu_load[30m])
Why it's wrong here
rate() is for counters, and node_cpu_load is a gauge.
- ✗
max(node_cpu_load[30m])
Why it's wrong here
Applying an aggregation operator like max() directly to a range vector is invalid syntax.
- ✗
topk(1, node_cpu_load[30m])
Why it's wrong here
topk requires an instant vector, not a range vector.
- ✓
max_over_time(node_cpu_load[30m])
Why this is correct
max_over_time() correctly computes the maximum value over the specified range vector for each time series.
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official CNCF / Linux Foundation exam blueprint
This PCA practice question is part of Courseiva's free CNCF / Linux Foundation 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 PCA exam.