Since cardinality is the number of possible groups depending on the dimensions the metrics have, the more combinations there are, the greater a metric’s cardinality is. This means that in fast-moving, modern cloud native environments where engineers are changing things fast and introducing potentially dozens of variables in a day, the multiplications on the basic set of telemetry data increases dramatically, causing high cardinality. What constitutes high” vs. “low cardinality is somewhat relative, but the better question to ask is when the ability to monitor and understand the environment gets out of hand for the engineering team.