OpenTelemetry is an open-source project that brings together tools, SDKs, and APIs for collecting telemetry--that is, logs, metrics, and traces---in a standardized way. The goal of the project is to help developers and operators instrument highly distributed applications and services to understand dependencies, monitor performance, and quickly troubleshoot problems. On today's Day Two Cloud podcast we explore OpenTelemetry and how it works. We also discuss the difference between visibility and observability, and why this matters. Our guest is Ben Hall.