Metric cardinality limits in OpenTelemetry: a practical guide

This article explains how OpenTelemetry’s metric cardinality limit protects process memory by folding excessive attribute combinations into a generic "overflow" data point. While this mechanism preserves total counts, it causes filtered queries and dashboards to undercount because the specific measurement attributes are stripped during overflow. The guide provides practical advice on avoiding high-cardinality attributes, estimating appropriate limits based on collection patterns, and monitoring for the `otel.metric.overflow=true` flag to ensure data reliability.