Werk #19414: otel_metrics: Delta values of metrics are now converted to cumulative values
| Component | Checks & agents | ||||
| Title | otel_metrics: Delta values of metrics are now converted to cumulative values | ||||
| Date | Mar 17, 2026 | ||||
| Level | Trivial Change | ||||
| Class | New Feature | ||||
| Compatibility | Incompatible - Manual interaction might be required | ||||
| Checkmk versions & editions |
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OpenTelemetry metrics sent to the Checkmk collector are now standardized to cumulative values.
Previously, delta values were used directly for "sum" metrics without tracking their aggregation temporality. This meant the code could not distinguish between a delta value (an increment since the last report) and a cumulative value (a running total). In practice, this led to a problem when a rate was computed: Calculating the rate of a delta value produces a second derivative (the rate of change of increments) rather than the actual per-second rate of the underlying counter.
By standardizing all values to cumulative before they reach the monitoring logic, we ensure consistent and semantically correct behavior:
- When a rate is computed (rate computation set to "Always compute the rate" or "Compute rates for all monotonic counters" for monotonic sums), the rate computation now operates on cumulative values. This yields a first derivative (the actual per-second rate of the counter) instead of the previous second derivative (rate of deltas).
- When no rate is computed (rate computation set to "Never compute a rate" or "Compute rates for all monotonic counters" for non-monotonic sums), the monitored value is now the cumulative total instead of a per-interval delta.
Because of this change, existing thresholds based on delta values may no longer trigger alerts correctly. If you use OpenTelemetry metrics with "sum" metrics in your Checkmk collector, review and update all thresholds configured in the OpenTelemetry service monitoring rule to reflect the new cumulative values.