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Instrumentation And Exporters

This domain covers how applications and targets expose metrics to Prometheus: client libraries, exporter design, and scrape-time configuration. Questions test Go client registration, metric type selection, cardinality control, and blackbox_exporter module semantics. Expect scenario-style items where you pick the right function, type, or config field rather than recite definitions.

51 questions8 easy31 medium12 hard

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What this domain covers

What to know about Instrumentation And Exporters

Be able to instrument a Go service with a client library, register and expose a metric, and select the correct metric type. The critical skill is controlling label cardinality and knowing that blackbox_exporter modules define how a probe runs, not which target is scraped.

Registering custom metrics in Go via prometheus.MustRegister and promhttp handler exposure

Choosing counter, gauge, and histogram types for process and request measurements

Diagnosing high cardinality from unbounded label values in custom exporters

Configuring blackbox_exporter modules for HTTP, TCP, ICMP, and DNS probes

Watch out for

Common Instrumentation And Exporters exam traps

  • ▸Using a Counter for a value that can decrease, such as current memory usage, instead of a Gauge.
  • ▸Labelling metrics with user IDs, request paths, or timestamps, exploding the series count in the TSDB.
  • ▸Confusing blackbox_exporter's module (probe type and settings) with the target URL passed at scrape time.

Question index

All Instrumentation And Exporters questions (51)

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1

Which TWO of the following are true about the node_exporter?

Medium
2

When creating a custom exporter, which component is responsible for scraping the data?

Medium
3

When configuring a custom exporter, how do you provide labels to a metric?

Medium
4

You are using the blackbox_exporter to monitor an HTTP endpoint. Which module configuration is required to check the HTTP status code?

Medium
5

Which THREE of the following are true about the Prometheus Text Exposition Format?

Medium
6

What is the effect of using a 'Summary' metric with client-side quantiles?

Medium
7

Which THREE components are typically involved in the standard Prometheus instrumentation and scraping process?

Hard
8

A Histogram has buckets [0.1, 0.5, 1, 5]. A request takes 0.7 seconds. Which buckets will be incremented?

Hard
9

You need to track the number of requests received by your application. Which metric type should you choose?

Easy
10

Which THREE of the following are standard ways to handle Prometheus metrics?

Hard
11

When writing a custom exporter in Python, what is the most common way to expose the metrics?

Medium
12

Which THREE of the following are key design considerations when creating a custom exporter?

Hard
13

You are monitoring a Linux server and need to track CPU usage. Which exporter is the standard choice for exposing hardware and OS metrics?

Easy
14

Which TWO of the following are true about the Gauge metric type?

Medium
15

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

Hard
16

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

Easy
17

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

Medium
18

When using the Prometheus Go client, what is the difference between a Gauge and a GaugeVec?

Hard
19

If you are using a Histogram, what is the purpose of the '_sum' metric?

Hard
20

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?

Hard
21

What does the `_count` suffix denote in a summary or histogram?

Medium
22

When running node_exporter, how can you disable specific collectors like 'textfile'?

Medium
23

You notice your custom exporter is timing out during scraping. What is the most likely cause?

Medium
24

You are seeing 'NaN' values in your gauge metrics. What does this indicate?

Hard
25

Which TWO of the following are true regarding Prometheus Histograms?

Medium
26

You are instrumenting a Go application. What is the standard way to register a metric?

Medium
27

Which TWO of the following are common reasons to use the Pushgateway?

Medium
28

Which TWO of the following are true about the Blackbox exporter?

Medium
29

You need to monitor the availability of a specific web endpoint from external locations using blackbox_exporter. What is the primary purpose of the 'module' configuration in blackbox_exporter?

Medium
30

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

Medium
31

What is the purpose of the 'le' label in a Histogram?

Hard
32

You are implementing a custom exporter for a legacy database. The database provides a single value representing the number of active connections. Which metric type should you use to best represent this data?

Hard
33

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

Medium
34

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

Medium
35

When using a Prometheus client library to instrument a Go application, which function call is typically used to register a new metric?

Easy
36

Which THREE of the following are common issues that cause scraping failures?

Hard
37

What is the recommended approach for metrics that only need to be exposed periodically?

Medium
38

Which THREE of the following are valid metric types in Prometheus?

Medium
39

Which metric type is most appropriate for tracking the current total number of active user sessions?

Easy
40

Which THREE of the following are common use cases for the node_exporter?

Easy
41

What is the impact of naming a metric starting with an underscore?

Medium
42

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

Medium
43

A developer wants to expose a metric that represents the current memory usage of a process. Which type is most appropriate?

Medium
44

Which action should be avoided when creating labels for custom metrics?

Medium
45

A developer wants to track the total number of requests received by a web service. Which metric type is most appropriate for this requirement?

Easy
46

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

Medium
47

Which THREE of the following are valid approaches to instrumenting an application?

Medium
48

What is the default port used by node_exporter?

Easy
49

Why are metric names required to follow a specific character set (e.g., alphanumeric and colons)?

Medium
50

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

Medium
51

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?

Medium

Frequently asked questions

What does the Instrumentation And Exporters domain cover on the PCA exam?
Be able to instrument a Go service with a client library, register and expose a metric, and select the correct metric type. The critical skill is controlling label cardinality and knowing that blackbox_exporter modules define how a probe runs, not which target is scraped.
How many questions are in this domain?
This page lists all 51 Instrumentation And Exporters questions in the PCA question bank. The actual exam draws from this domain proportionally to its weighting in the official exam blueprint.
What is the best way to practise this domain?
Start with a short focused session (10 questions) to identify gaps, then work through explanations. Repeat with a longer session once the weak areas feel solid.
Can I practise only Instrumentation And Exporters questions?
Yes — the session launcher on this page filters questions to this domain only. Choose any session length for inline explanations and scoring.
Prometheus Certified Associate (PCA, CNCF/Linux Foundation) (PCA) Instrumentation And Exporters Practice Questions