OpenTelemetry is primarily definitions of protocols, APIs and semantic conventions for instrumentation data (traces, metric and logs, in decreasing order of mat

OpenTelemetry is primarily definitions of protocols, APIs and semantic conventions for instrumentation data (traces, metric and logs, in decreasing order of maturity). OpenTelemetry also ships the Collector, which is like a patch-bay accepting many different data formats and sending on in more formats. Grafana Agent is a bundling of a bunch of things for collecting instrumentation. The idea is to simplify deployment and allow opinionated setup. The Agent can upload to Grafana Cloud, or to any compatible backend (all the basic components are open source). In particular it bundles Prometheus Agent, which does metrics collection from anything Prometheus-compatible but not queries, and OTel Collector. It also bundles Promtail for logs. (I work for Grafana Labs)