PCA PCA Recording Rules & Aggregation

Question 1

What is the primary purpose of recording rules in Prometheus?

Accepted Answer

To precompute expensive PromQL expressions and store results as new time series

Answer

Recording rules evaluate PromQL expressions on a schedule and write the results as new metric series, making repeated queries faster.

Question 2

What naming convention does Prometheus recommend for recording rule metric names?

Accepted Answer

level:metric:operations (e.g., job:http_requests_total:rate5m)

Answer

The recommended format is level:metric:operations, encoding aggregation level, source metric, and transformations into the name.

Question 3

In a Prometheus rule file, which YAML key defines a recording rule's output metric name?

Accepted Answer

record

Answer

The `record` key in a rule group entry specifies the name of the new time series that the rule's expression will be written to.

Question 4

How are recording rule files loaded into Prometheus?

Accepted Answer

Via the rule_files directive in prometheus.yml listing file paths or globs

Answer

The rule_files section of prometheus.yml accepts file paths and glob patterns pointing to YAML files containing rule groups.

Question 5

What happens when Prometheus evaluates a recording rule that produces no series (empty result)?

Accepted Answer

No new data points are written for that evaluation interval

Answer

If a recording rule returns an empty result, Prometheus simply writes nothing for that interval, leaving a gap in the recorded metric.

(PCA) Prometheus Certified Associate Practice Test