PCA Instrumentation And Exporters — 15 Questions

Question 1

You need to monitor the duration of database queries. Which metric type is best for calculating quantiles on the server side?

Accepted Answer

Histogram. Summaries calculate configurable quantiles on the client side, while Histograms require server-side calculations.

Answer

Gauge

Answer

Counter

Answer

Summary

Question 2

You want to monitor the status of a specific SSL certificate via blackbox_exporter. Which module is designed for this?

Accepted Answer

http_2xx. The http_2xx module, when configured with TLS settings, can check certificate expiry via the probe_ssl_earliest_cert_expiry metric.

Answer

tcp_connect

Answer

ssl_check

Answer

cert_monitor

Question 3

You need to expose metrics from a legacy application that only logs to a file. What should you do?

Accepted Answer

Use the node_exporter textfile collector. The node_exporter textfile collector is designed to read metrics from a specific directory where you can drop files containing Prometheus-formatted data.

Answer

None of the above

Answer

Use a blackbox exporter

Answer

Use Pushgateway

Answer

Use a custom exporter

Question 4

Which of the following is a correct unit suffix for Prometheus metrics?

Accepted Answer

_seconds. Prometheus recommends using base units (e.g., seconds for duration, bytes for memory) and appending the unit to the name.

Answer

_total

Answer

_sum

Answer

_count

Question 5

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 6

Which TWO factors directly influence the accuracy of quantile calculations when using Prometheus Summary metrics?

Accepted Answer

The configured quantiles (e.g., 0.9, 0.99).. Summaries compute quantiles on the client side, and accuracy is determined by the configured quantiles and the sliding time window over which they are calculated.

Answer

The total number of instances scraping the metric.

Answer

The CPU architecture of the client host.

Answer

The number of buckets defined in the configuration.

Question 7

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 8

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

Accepted Answer

Counter. A counter is a cumulative metric that represents a single monotonically increasing counter whose value can only increase or be reset to zero on restart.

Answer

Summary

Answer

Gauge

Answer

Histogram

Question 9

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

Accepted Answer

Using high-cardinality labels. Adding high-cardinality data (like user IDs or unique request IDs) to labels causes an explosion in the number of time series, which can crash Prometheus.

Answer

Using static labels

Answer

Adding job labels

Answer

Adding instance labels

Question 10

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

Question 11

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

Accepted Answer

http_2xx. The http_2xx module is the standard configuration for checking that an endpoint returns a successful HTTP status code.

Answer

dns_query

Answer

tcp_connect

Answer

icmp_ping

Question 12

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

Accepted Answer

Gauge. A Gauge is the correct metric type because it represents a value that can arbitrarily go up or down over time, such as current memory usage, CPU load, or temperature. Prometheus gauges expose instantaneous snapshots via Set(), Inc(), and Dec() operations, making them ideal for measuring fluctuating resource consumption. Memory usage is not cumulative and can decrease when a process releases memory, which rules out Counter.

Answer

Counter

Answer

Summary

Answer

Histogram

Question 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?

Accepted Answer

node_exporter. node_exporter is the standard Prometheus exporter for hardware and OS metrics exposed by *NIX kernels.

Answer

mysqld_exporter

Answer

blackbox_exporter

Answer

pushgateway

Question 14

What is the default port used by node_exporter?

Accepted Answer

9100. The standard Prometheus convention for node_exporter is port 9100.

Answer

9115

Answer

9090

Answer

8080

Question 15

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

Accepted Answer

--no-collector.textfile. Collectors can be disabled using the --no-collector.<name> flag.

Answer

collector.textfile=false

Answer

exclude=textfile

Answer

--disable-textfile