PCA Practice Exam 4 — 20 Questions

Question 1

Which TWO of the following should be considered when defining metric names?

Accepted Answer

Use descriptive, clear names. Names should be descriptive and use the unit suffix as per conventions.

Answer

Avoid using underscores

Answer

Use random IDs to ensure uniqueness

Answer

Include the instance name in the metric

Question 2

Which THREE of the following are valid metric types supported natively by Prometheus client libraries?

Accepted Answer

Histogram. The four core metric types in Prometheus are Counter, Gauge, Histogram, and Summary.

Answer

Snapshot

Answer

Set

Question 3

You want to notify different teams based on the 'service' label of an alert. Where should you configure this logic?

Accepted Answer

In the Alertmanager configuration. The Alertmanager configuration file contains the routing tree that maps alerts to receivers based on labels.

Answer

In the node exporter config

Answer

In the Grafana data source

Answer

In the Prometheus alerting rule

Question 4

You have a recording rule that references a metric that doesn't exist. What is the impact?

Accepted Answer

The rule evaluation results in no data. The recording rule will be evaluated, but because the expression returns no data, no new time series will be created for that rule.

Answer

Prometheus logs a critical error

Answer

The entire server crashes

Answer

The rule is automatically disabled

Question 5

Your application has a short-lived batch job that finishes before the Prometheus server can scrape it. What architectural component should be used?

Accepted Answer

Pushgateway. The Pushgateway is designed to allow ephemeral and batch jobs to expose their metrics to Prometheus.

Answer

Prometheus API

Answer

Alertmanager

Answer

node_exporter

Question 6

Which THREE of these are common Prometheus data sources?

Accepted Answer

Static configuration files.. Kubernetes service discovery, static file configs, and Consul are standard discovery methods.

Answer

User manual entry in the UI.

Answer

Direct SQL database connections.

Question 7

Which of these is NOT a valid Alertmanager receiver type?

Accepted Answer

SQL. While Alertmanager supports many integrations (Webhook, Email, PagerDuty), 'SQL' is not a native built-in receiver type.

Answer

Webhook

Answer

Email

Answer

PagerDuty

Question 8

Which TWO of the following are valid fields in a Prometheus alerting rule definition?

Accepted Answer

expr. A rule must have an 'alert' name and an 'expr' query.

Answer

timeout

Answer

retries

Answer

target

Question 9

What is the primary function of the 'blackbox_exporter' in a monitoring architecture?

Accepted Answer

Endpoint probing. It allows monitoring of endpoints from the outside (blackbox perspective) rather than the inside (whitebox instrumentation).

Answer

Database performance

Answer

Log aggregation

Answer

Hardware monitoring

Question 10

Which tool would you use to monitor the availability of a website from various geographic locations?

Accepted Answer

blackbox_exporter. The blackbox_exporter is the standard tool for probing the availability of HTTP, TCP, or DNS services.

Answer

node_exporter

Answer

Pushgateway

Answer

Prometheus API

Question 11

You have a histogram metric tracking request durations. You need to calculate the 99th percentile across all instances in a cluster. Why is this difficult with standard Prometheus metrics?

Accepted Answer

Aggregating histograms requires complex math because they track bucket counts, not raw values.. Histograms track counts in predefined buckets. Without knowing the exact distribution of values within those buckets, calculating accurate quantiles across multiple instances or time windows is an approximation.

Answer

Histograms can only be used on a single instance.

Answer

The Prometheus server does not support mathematical operations.

Answer

Histograms are not designed to be aggregated across multiple labels.

Question 12

Which Alertmanager feature would you use to prevent a 'ServiceDown' alert from firing if a 'GlobalNetworkOutage' alert is already active?

Accepted Answer

Inhibition. Inhibition rules allow one alert to suppress another based on matching labels.

Answer

Grouping

Answer

Silencing

Answer

Routing

Question 13

When setting up Alertmanager, what happens if you have no route defined for an alert?

Accepted Answer

The alert is sent to the root route. If an alert matches no specific route, it will fall back to the root route of the configuration tree.

Answer

The alert triggers an error

Answer

The alert is sent to all receivers

Answer

The alert is dropped

Question 14

You need to ensure that an alert remains 'firing' for 5 minutes before the Alertmanager is notified. Which field in the Prometheus alerting rule should you configure?

Accepted Answer

for. The 'for' field in a Prometheus alerting rule specifies the duration for which a condition must be true before the alert transitions from 'pending' to 'firing'.

Answer

pending_duration

Answer

delay

Answer

hold_time

Question 15

What is the purpose of the 'instance' label in Prometheus?

Accepted Answer

To identify the target. It is an automatically added label that identifies the target (host:port) that the metric was scraped from.

Answer

To filter alerts

Answer

To identify the user

Answer

To identify the job

Question 16

When instrumenting an application, why is it recommended to use a fixed set of label names?

Accepted Answer

To avoid cardinality explosion. Dynamically changing label names creates new time series, which can lead to cardinality explosion and storage issues.

Answer

To increase resolution

Answer

For better formatting

Answer

To simplify coding

Question 17

You are troubleshooting high cardinality in your metrics. What is a common cause for this in a custom exporter?

Accepted Answer

Including dynamic values like IDs or timestamps in label values.. High cardinality occurs when a label value has an unbounded number of unique values (like a request ID or a timestamp), causing a massive explosion in the number of unique time series.

Answer

Using too many different metrics.

Answer

Scraping the exporter too frequently.

Answer

Using the wrong metric type for a simple count.

Question 18

When using the 'repeat_interval' in Alertmanager, what does it define?

Accepted Answer

How often to resend firing alerts. The repeat_interval defines how long to wait before re-sending a notification for an alert that is still active.

Answer

The timeout for the receiver

Answer

The TTL of the alert

Answer

How long to wait before firing

Question 19

If you have a scrape_interval of 15s, what is the recommended minimum scrape_timeout?

Accepted Answer

10s. The timeout should generally be slightly less than or equal to the scrape_interval, but it must be sufficient to allow the target to respond.

Answer

5s

Answer

30s

Answer

15s

Question 20

When implementing a custom exporter, what format must the output follow to be correctly scraped by Prometheus?

Accepted Answer

Prometheus Text Format. Prometheus requires a text-based format where each metric is represented by lines, including name, labels, and values.

Answer

JSON

Answer

XML

Answer

Binary Protobuf