OpenTelemetry

Observability lets you understand a system from the outside by letting you ask questions about that system without knowing its inner workings. Furthermore, it allows you to easily troubleshoot and handle novel problems, that is, “unknown unknowns”. It also helps you answer the question “Why is this happening?”

To ask those questions about your system, your application must be properly instrumented. That is, the application code must emit signals such as traces, metrics, and logs. An application is properly instrumented when developers don’t need to add more instrumentation to troubleshoot an issue, because they have all of the information they need.

OpenTelemetry is the mechanism by which application code is instrumented to help make a system observable.

オブザーバビリティとはシステム内部に付いて知らずともシステムについて理解できること

これを実現するためにはアプリケーションがinstrumentedされている必要がある

instrumentedとはアプリケーションがログ、トレースといったシグナルなどを発信できること

OpenTelemetryでそれを実現できる