Thanos Ruler

Thanos Ruler enables a unique feature for advanced use cases: evaluating Prometheus rules across multiple Prometheus instances. For example, consider a service you have deployed across multiple regions with a Prometheus deployment in each region responsible for monitoring its corresponding instance of the service. Thanos Ruler would enable you to evaluate Prometheus rules across all of those Prometheus instances to obtain a more holistic view of your service. This is great for measuring things such as service-level objectives (SLOs).

Thanos Ruler accomplishes this by connecting to one or more Thanos Query endpoints to run queries against. If more than one is specified, it performs round-robin balancing of queries. In other words, a rule’s query is not evaluated by every specified Query instance – only one is chosen and used per query.

Data produced by evaluating recording rules is stored in a local TSDB in the same manner that it would be on Prometheus...