What is Metrics, logs and traces?

The three main kinds of telemetry: numbers over time, event records, and the path of a single request.

In plain English

Metrics are numbers sampled over time, such as requests per second or memory used, and are cheap to store and good for alerting. Logs are timestamped records of individual events, good for detail. Traces follow one request as it passes through several services, showing where time was spent.

Example

A metric shows errors rising at 10:05. A trace points at the payments service. The logs from that service show a timeout to the bank.

Easy to confuse with

• Observability: These are the signals. Observability is how well they let you understand the system.

Where you will meet it

This idea belongs to the subject area of these practice tests. We do not publish or predict real exam questions.

• OpenTelemetry OTCA practice tests
• Prometheus PCA practice tests

Related terms

• Observability: How well you can understand what is happening inside a system from the data it produces.
• OpenTelemetry Collector: A vendor-neutral service that receives telemetry, processes it and sends it on to one or more tools.
• PromQL: The query language used to read and calculate on Prometheus metrics.

Written and checked by the Be Ready Education team, last reviewed 2 November 2026. General study information, not professional advice. Providers change names and rules, so confirm details on the official documentation. Not affiliated with, endorsed by or sponsored by any certification vendor or exam body. Certification names, exam codes and product names are trademarks of their respective owners and are used only to identify the exam a practice product prepares for. Our questions are original and are not actual exam questions.