PCA Practice Test 8 — 10 Questions

Question 1

In the Prometheus data model, what is a 'sample'?

Accepted Answer

A value and a timestamp. A sample is a value-timestamp pair associated with a specific series.

Answer

The metric name

Answer

A label key-value pair

Answer

An alert rule

Question 2

Which mechanism allows Prometheus to discover targets by reading a list from a file?

Accepted Answer

file_sd_configs. file_sd_configs is designed to read target lists from JSON or YAML files.

Answer

dns_sd_configs

Answer

static_configs

Answer

consul_sd_configs

Question 3

A batch job runs for only 30 seconds every hour. How should you expose these metrics to Prometheus?

Accepted Answer

Use the Pushgateway. The Pushgateway is designed specifically for short-lived jobs that cannot be scraped directly.

Answer

Use an exporter sidecar

Answer

Increase scrape interval to 1 hour

Answer

Add a scrape_config for the batch job

Question 4

When using the 'scrape_timeout', what happens if the timeout is reached?

Accepted Answer

The scrape is marked as failed. If the timeout is reached, the scrape is aborted, and a 'up{job=...} == 0' metric is recorded.

Answer

It automatically retries once

Answer

The previous value is kept indefinitely

Answer

The scrape continues silently

Question 5

Which PromQL aggregator should be used to count the total number of active time series matching a selector?

Accepted Answer

count(up). The count operator counts the number of time series in an instant vector.

Answer

sum(up)

Answer

len(up)

Answer

total(up)

Question 6

What is the default value for the scrape interval?

Accepted Answer

1m. The default scrape interval in Prometheus is 1 minute.

Answer

10s

Answer

30s

Answer

5m

Question 7

What is the primary language used to query Prometheus data?

Accepted Answer

PromQL. PromQL (Prometheus Query Language) is the functional query language for Prometheus.

Answer

Regex

Answer

GraphQL

Answer

SQL

Question 8

You need to calculate the per-second rate of increase for a counter metric over the last 10 minutes. Which function is most appropriate?

Accepted Answer

rate(metric[10m]). rate() is the standard function for calculating the per-second rate of increase over a range vector.

Answer

increase(metric[10m])

Answer

irate(metric[10m])

Answer

delta(metric[10m])

Question 9

What is the purpose of the 'offset' modifier in a PromQL query?

Accepted Answer

To change the time range of a query to a point in the past.. The 'offset' modifier allows querying data from the past relative to the current time.

Answer

To remove specific label dimensions.

Answer

To filter out noise from the last 5 minutes.

Answer

To increase the precision of a rate calculation.

Question 10

You need to perform a binary operation between two vectors where the left vector has labels {job="api", instance="a"} and the right vector has labels {job="api"}. You want to match them using the job label while retaining the instance label from the left side. Which modifier configuration is correct?

Accepted Answer

vector_a * on(job) group_left(instance) vector_b. To match on a subset of labels while retaining extra labels on the left side during a one-to-many or many-to-one operation, group_left must be used with the on modifier.

Answer

vector_a * on(instance) group_left(job) vector_b

Answer

vector_a * on(job) group_right(instance) vector_b

Answer

vector_a * ignoring(instance) group_left vector_b