Summary

Distributed systems need a new approach to observability that simplifies investigating incidents and minimizes the time to resolve issues. This approach should focus on human experience such as data visualization, the correlation across telemetry signals, and analysis automation. It requires structured, correlated telemetry signals that work together and new tools that leverage them to build a rich experience.

Distributed tracing is one such signal – it follows requests through any system and describes service operations with spans, the events representing operations in the system. .NET supports distributed tracing and integrates natively with OpenTelemetry, which is a cross-language platform to collect, process, and export traces, metrics, and logs in a vendor-agnostic way. Most modern vendors are compatible with OpenTelemetry and leverage distributed tracing capabilities. The OpenTelemetry ecosystem includes a diverse set of shared instrumentation libraries that automate common telemetry collection needs.

Distributed tracing enables correlation and causation by propagating context within the process and between services. OpenTelemetry defines standard semantics for common technologies so that vendors can build trace visualizations, application maps, shared dashboards, alerts, or queries that rely on consistent and standard attributes. Trace context and consistent attributes enable correlation between spans, logs, metrics, and any other signals coming from your system.

Individual issues can be efficiently analyzed with distributed tracing and investigations into widespread performance issues rely on attributes and timestamp correlation on metrics and across traces. Observability vendors may automate this analysis.

A combination of metrics, traces, and events gives the right number of details. Metrics allow us to receive unbiased data in a cost-effective way. By querying traces and events over high-cardinality attributes, we can answer ad hoc questions about the system.

In the next chapter, we’ll get hands-on experience with distributed tracing. We’ll build a demo application and explore native tracing capabilities in .NET.