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 a Cloud Native Computing Foundation (CNCF) project.
Why OpenTelemetry?
With the rise of cloud computing, microservices architectures, and ever-more complex business requirements, the need for Observability has never been greater. 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.
In order to make a system observable, it must be instrumented. That is, the code must emit traces, metrics, and logs. The instrumented data must then be sent to an Observability backend.
OpenTelemetry does two important things:
- Allows you to own the data that you generate rather than be stuck with a proprietary data format or tool.
- Allows you to learn a single set of APIs and conventions
These two things combined enables 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.
Major 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 out of the box.
OpenTelemetry is supported by 40+ 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 will not need to extend OpenTelemetry, the project is designed to make it possible at nearly every level.
History
OpenTelemetry 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. However, neither project was fully able to solve the problem on its own, and so the two projects merged to form OpenTelemetry so that they could combine their strengths and truly offer a single standard.
If you are currently using OpenTracing or OpenCensus, you can learn how to migrate to OpenTelemetry here.
What OpenTelemetry is not
OpenTelemetry is not an observability back-end like Jaeger, Prometheus, or commercial vendors. OpenTelemetry is focused on the generation, collection, management, and export of telemetry data. The storage and visualization of that data is intentionally left to other tools.
What next?
- Getting started — jump right in!
- Learn about OpenTelemetry concepts.