Open Observability Summit + OTel Community Day 2025

As OpenTelemetry adoption expands, one common pain point across the community is metric cardinality. High-cardinality metrics—especially those with user- or host-level tags—can overload backends with unique time series, driving up costs and reducing signal quality. Many teams only notice once the vendor bill arrives.

In this talk, we’ll explore how to use the OpenTelemetry Collector and OTTL (OpenTelemetry Transformation Language) to proactively reduce metric cardinality. Learn how to spot costly metrics, reshape or drop them with the filter processor, test changes with the OTTL Playground, and implement a control plane to safely evolve filtering rules.

Whether you’re using Prometheus, a commercial vendor, or OpenTelemetry-native pipelines, this session offers practical, open-source strategies to reduce noise, improve signal, and keep observability costs sustainable.