Kubernetes
A cluster is where alert storms are born. One node runs out of memory and every workload on it dies at once — this is the case promotion was built for, and where SaviourOps goes deepest.
The grouping is stricter than it looks, which is the point — a collapse rule that fires too easily is just a different kind of noise.
Drift is what makes a likely-cause verdict possible at all. Without a change history there is nothing to correlate a failure against.
Two of them, installed with one command each. No application code changes and no SDK in the request path.
Connect one cluster and watch a week of alerts sort themselves into the handful that actually mattered.