PCA Practice Test 11 — 15 Questions

Question 1

Which TWO of the following are true about the Pushgateway?

Accepted Answer

Metrics must be deleted manually. Pushgateway is for batch jobs and requires manual deletion of metrics.

Answer

It is a drop-in for standard scraping

Answer

It stores metrics persistently

Answer

It automatically expires metrics

Question 2

When using the Pushgateway, what happens if you push a metric with the same name and labels as an existing one?

Accepted Answer

It overwrites the old value. The Pushgateway overwrites the existing metric with the new value provided in the push request.

Answer

It creates a new series

Answer

It rejects the push

Answer

It adds to the existing value

Question 3

Which selector syntax correctly matches all time series where the environment label does NOT equal production?

Accepted Answer

http_requests_total{environment!="production"}. The != operator is the standard negative equality matcher in PromQL label selectors.

Answer

http_requests_total{environment=~"^((?!production).)*$"}

Answer

http_requests_total{environment!~"production"}

Answer

http_requests_total{environment!^"production"}

Question 4

A Prometheus alert expression uses rate(http_requests_total[5m]) > 10. During a service restart, counter resets occur. How does the rate() function account for these counter resets?

Accepted Answer

It assumes the counter reset to zero and adds the new value to the previous value.. The rate() function automatically detects decreases in counter values (resets) and adjusts the calculation assuming the counter restarted at zero.

Answer

It treats the negative difference as an error and returns 0 for the entire range.

Answer

It adds a fixed offset value configured in Prometheus global settings.

Answer

It drops the samples surrounding the reset, resulting in a null value for that evaluation.

Question 5

Which THREE items are standard techniques to reduce metric cardinality?

Accepted Answer

Aggregating raw metrics into broader categories.. Dropping labels, aggregating metrics, and limiting metric frequency are standard ways to reduce cardinality.

Answer

Increasing the scrape interval.

Answer

Adding unique IDs to every label.

Question 6

Your team is defining Service Level Objectives (SLOs) for a web application. Which metric is most indicative of the 'Traffic' golden signal?

Accepted Answer

Number of requests per second. Traffic is a measure of demand on the system, typically represented by request rate per second.

Answer

Database connection pool size

Answer

Total disk I/O wait

Answer

Number of active error logs

Answer

Average CPU utilization percentage

Question 7

When a Prometheus server is restarted, how does it recover the in-memory data?

Accepted Answer

It reads the WAL. It replays the Write-Ahead Log (WAL) to reconstruct the in-memory head block.

Answer

It only keeps the last 5 minutes

Answer

It queries the remote store

Answer

It re-scrapes all targets

Question 8

You are monitoring server hardware metrics using node_exporter. You observe that the metrics are not showing up in Prometheus. Which initial troubleshooting step is most effective?

Accepted Answer

Verify node_exporter is listening on the expected port and accessible.. The node_exporter must be running and listening on the expected port (9100 by default) for the Prometheus server to scrape it. Verifying the port ensures the endpoint is reachable.

Answer

Increase the scrape interval in the Prometheus configuration.

Answer

Disable all collectors in node_exporter to reduce overhead.

Answer

Check if the Prometheus server is running in high availability mode.

Question 9

How does PromQL handle operator precedence between arithmetic operators like multiplication (*) and addition (+)?

Accepted Answer

Multiplication has higher precedence than addition.. PromQL follows standard mathematical order of operations, where multiplication and division take precedence over addition and subtraction.

Answer

Operators are evaluated strictly from left to right regardless of type.

Answer

Operators are evaluated strictly from right to left.

Answer

Addition has higher precedence than multiplication.

Question 10

You are joining an instant vector of application versions with an instant vector of metrics using a many-to-one relationship. The application version vector has more labels than the metric vector. Which keyword must be appended to the matching modifier to include labels from the 'many' side?

Accepted Answer

group_left. In many-to-one or one-to-many matches, group_left or group_right must be provided to specify which side supplies additional labels.

Answer

include_labels

Answer

keep_all

Answer

group_right

Question 11

How does the 'stale marker' work in Prometheus?

Accepted Answer

It prevents the graph from showing data after the target goes down.. When a target stops responding, Prometheus writes a stale marker to the TSDB so that graphs stop at the last known value rather than showing an infinite line or incorrect data.

Answer

It restarts the scrape job.

Answer

It sends an alert.

Answer

It deletes the metric data.

Question 12

Which THREE of these represent the Four Golden Signals?

Accepted Answer

Errors. Latency, Traffic, Errors, and Saturation are the set.

Answer

Memory Usage

Answer

Availability

Question 13

Which TWO are true about the 'Summary' metric type?

Accepted Answer

They provide client-side quantiles.. Summaries are pre-calculated at the client side and provide quantiles.

Answer

They only support counts.

Answer

They are easily aggregatable across instances.

Answer

They are identical to Histograms.

Question 14

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 15

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