PCA Alerting And Dashboarding Practice Test 2 — 15 Questions

Question 1

You need to prevent an alert from firing if a maintenance window is active. How should you approach this in Alertmanager?

Accepted Answer

Use a Silence. Silences are the standard way to prevent specific alerts from firing during a known maintenance period.

Answer

Delete the alerting rule

Answer

Modify the routing tree

Answer

Add a 'skip' label to the rule

Question 2

You have a global Alertmanager configuration where you want to suppress 'DiskSpaceLow' alerts if 'InstanceDown' is active for the same host. Which mechanism accomplishes this?

Accepted Answer

Inhibition rules. Inhibition rules in Alertmanager are designed to suppress a set of alerts when another set of alerts is already firing. They match on labels, so you can define an inhibition rule that mutes 'DiskSpaceLow' alerts if an 'InstanceDown' alert with the same host label is active. This is exactly the use case described: suppressing dependent alerts when a more fundamental alert is firing.

Answer

Route tree

Answer

Repeat intervals

Answer

Grouping

Question 3

You notice that recording rules are consuming too much CPU on your Prometheus server. What is the most effective way to reduce the load while keeping data available?

Accepted Answer

Increase the evaluation_interval. Recording rules in Prometheus are evaluated at the interval defined by 'evaluation_interval' in the rule group. Increasing the evaluation_interval means rules run less frequently, which directly reduces CPU load on the Prometheus server while keeping the recorded time series available for querying.

Answer

Decrease the evaluation_interval

Answer

Move recording rules to Alertmanager

Answer

Delete all indices

Question 4

Which file format is used to define Prometheus alerting rules?

Accepted Answer

YAML. Prometheus alerting rules are defined in YAML format. The rule files are specified in the Prometheus configuration and contain groups of rules with expressions and durations. YAML is the standard for Prometheus configuration files.

Answer

JSON

Answer

TOML

Answer

XML

Question 5

You are seeing 'Alerting rule evaluation error' in your logs. What is the most likely cause?

Accepted Answer

Invalid PromQL in the expression. The error message 'Alerting rule evaluation error' originates from the Prometheus rule evaluation engine when it cannot successfully execute the PromQL expression defined in a rule. The most common cause is a syntactically or semantically invalid PromQL expression — for example, referencing a non-existent metric, using an unsupported function, or mismatching label matchers. Prometheus logs this error per rule per evaluation cycle, so the fix is to validate the expression in the Prometheus expression browser or with promtool check rules.

Answer

Alertmanager is down

Answer

Too many dashboards

Answer

Prometheus is out of disk space

Question 6

Which Grafana panel type is best for showing a trend of a metric over time?

Accepted Answer

Time series. The Time series panel is the standard for plotting metrics over time.

Answer

Table

Answer

Stat

Answer

Bar gauge

Question 7

What is the purpose of the 'labels' field in an alerting rule?

Accepted Answer

To add metadata for routing and filtering. Labels allow you to attach metadata to the alert, which can then be used in Alertmanager for routing and grouping.

Answer

To define the alert message body

Answer

To select the target server

Answer

To set the alert severity level

Question 8

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 9

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 10

What happens to your alerts if the Alertmanager configuration file contains a syntax error?

Accepted Answer

Alertmanager continues using the previous configuration. If the configuration is invalid, Alertmanager will fail to reload, and it will continue using the last known good configuration.

Answer

Prometheus stops scraping

Answer

Alertmanager crashes immediately

Answer

All alerts are dropped

Question 11

Which annotation is commonly used to provide a human-readable description in an alert?

Accepted Answer

description. The 'summary' or 'description' annotations are standard practices for providing context in alert notifications.

Answer

severity

Answer

instance

Answer

job

Question 12

In Alertmanager, what is the role of the 'continue' field in a route?

Accepted Answer

To force the alert to be sent to multiple routes. The 'continue' field in an Alertmanager route, when set to true, allows the alert to continue matching subsequent sibling routes. This means the alert can be sent to multiple receivers, effectively forcing it to be routed to multiple destinations.

Answer

To keep the alert firing after resolution

Answer

To ignore duplicate alerts

Answer

To restart the Alertmanager process

Question 13

Which tool allows you to visualize Prometheus alerts directly in a web UI?

Accepted Answer

Alertmanager UI. Alertmanager ships with a built-in web UI (typically served on port 9093) that displays active alerts, silences, and grouping status, allowing operators to visualize and manage alerts directly. It is the canonical tool for inspecting which alerts are firing, which are silenced, and how they are grouped before notification. The Prometheus server's own UI shows firing alerts via the /alerts endpoint, but the Alertmanager UI is the dedicated interface for alert lifecycle management.

Answer

Node Exporter

Answer

Pushgateway

Answer

Prometheus CLI

Question 14

You have a recording rule that uses 'sum() by (instance)'. Why might this be inefficient for large clusters?

Accepted Answer

It can lead to high cardinality if 'instance' has many values. Using 'sum() by (instance)' in a recording rule aggregates metrics per instance, and if the 'instance' label has many unique values (e.g., in a large cluster with many nodes or pods), it creates a high number of time series. This high cardinality increases memory and storage usage in Prometheus, leading to inefficiency and potential performance degradation. The correct answer identifies high cardinality as the primary concern.

Answer

It blocks concurrent queries

Answer

It uses too much disk I/O

Answer

It slows down the network

Question 15

You want to ensure that if the Alertmanager cluster loses communication, alerts are still sent. Which configuration helps achieve this?

Accepted Answer

Use the --cluster.peer flag. High Availability (HA) for Alertmanager is achieved by running multiple instances and using the '--cluster.peer' flag to link them.

Answer

Disable grouping

Answer

Set repeat_interval to 0

Answer

Use a load balancer only