query: Add metric to track healthy/unhealthy endpoints #8492
+21
−3
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Changes
Adds
thanos_query_endpoints_count
metric to track healthy and unhealthy endpoints.Use case: when not using strict endpoints, the endpoints will silently go stale and there is no way of knowing if queries/rules are getting wrong/no results (wrong results because the data can be partial with stale endpoints). This metric can be useful to alert on if endpoints become unhealthy (for example load-balancers being down).
If there is some other way to identify such silently failing queries, this PR can be closed in favor of that.
Verification
TestEndpointSetUpdate
was panicking locally even without this change, so I have not written unit tests for this yet.