What is OpenTelemetry?

OpenTelemetry is an Observability framework and toolkit designed to create and manage telemetry data such as traces, metrics, and logs. Crucially, OpenTelemetry is vendor- and tool-agnostic, meaning that it can be used with a broad variety of Observability backends, including open source tools like Jaeger and Prometheus, as well as commercial offerings.

OpenTelemetry is not an observability backend like Jaeger, Prometheus, or other commercial vendors. OpenTelemetry is focused on the generation, collection, management, and export of telemetry. A major goal of OpenTelemetry is that you can easily instrument your applications or systems, no matter their language, infrastructure, or runtime environment. Crucially, the storage and visualization of telemetry is intentionally left to other tools.

What is observability?

Observability is the ability to understand the internal state of a system by examining its outputs. In the context of software, this means being able to understand the internal state of a system by examining its telemetry data, which includes traces, metrics, and logs.

To make a system observable, it must be instrumented. That is, the code must emit traces, metrics, or logs. The instrumented data must then be sent to an observability backend.

Why OpenTelemetry?

With the rise of cloud computing, microservices architectures, and increasingly complex business requirements, the need for software and infrastructure observability is greater than ever.

OpenTelemetry satisfies the need for observability while following two key principles:

1. You own the data that you generate. There’s no vendor lock-in.
2. You only have to learn a single set of APIs and conventions.

Both principles combined grant teams and organizations the flexibility they need in today’s modern computing world.

If you want to learn more, take a look at OpenTelemetry’s mission, vision, and values.

Main OpenTelemetry components

OpenTelemetry consists of the following major components:

• A specification for all components
• A standard protocol that defines the shape of telemetry data
• Semantic conventions that define a standard naming scheme for common telemetry data types
• APIs that define how to generate telemetry data
• Language SDKs that implement the specification, APIs, and export of telemetry data
• A library ecosystem that implements instrumentation for common libraries and frameworks
• Automatic instrumentation components that generate telemetry data without requiring code changes
• The OpenTelemetry Collector, a proxy that receives, processes, and exports telemetry data
• Various other tools, such as the OpenTelemetry Operator for Kubernetes, OpenTelemetry Helm Charts, and community assets for FaaS

OpenTelemetry is used by a wide variety of libraries, services and apps that have OpenTelemetry integrated to provide observability by default.

OpenTelemetry is supported by numerous vendors, many of whom provide commercial support for OpenTelemetry and contribute to the project directly.

Extensibility

OpenTelemetry is designed to be extensible. Some examples of how it can be extended include:

• Adding a receiver to the OpenTelemetry Collector to support telemetry data from a custom source
• Loading custom instrumentation libraries into an SDK
• Creating a distribution of an SDK or the Collector tailored to a specific use case
• Creating a new exporter for a custom backend that doesn’t yet support the OpenTelemetry protocol (OTLP)
• Creating a custom propagator for a nonstandard context propagation format

Although most users might not need to extend OpenTelemetry, the project is designed to make it possible at nearly every level.

History

OpenTelemetry is a Cloud Native Computing Foundation (CNCF) project that is the result of a merger between two prior projects, OpenTracing and OpenCensus. Both of these projects were created to solve the same problem: the lack of a standard for how to instrument code and send telemetry data to an Observability backend. As neither project was fully able to solve the problem independently, they merged to form OpenTelemetry and combine their strengths while offering a single solution.

If you are currently using OpenTracing or OpenCensus, you can learn how to migrate to OpenTelemetry in the Migration guide.

What next?

• Getting started — jump right in!
• Learn about OpenTelemetry concepts.