Hey y'all, does druid publish any metrics specifically for ingestion autoscaling? I'd like to make an alert based around (for example) if autoscaling has increased the number of tasks more than 5 times over the last 24 hours. I could just go based on the number of tasks but that'd cause redundant alerts if it was manual action scaling them.

Not sure about metrics, but you can see scaling activities by viewing the supervisor audit history https://druid.apache.org/docs/latest/api-reference/supervisor-api/#get-audit-history-for-a-specific-supervisor

The trick here is that I specifically want to see scaling activity caused by the autoscaler unfortunately. Though thinking about it more I think I might be good, it's probably smarter to alert purely based on the number of tasks rather than the number of actions. Thanks Kyle!

@Danny Wilkins are you talking about metrics based in what you can scale the ingestion nodes ?

Emitting, say, the number of tasks added/removed by the autoscaler as metrics to save us having to do correlation and guessing what's autoscaler vs manual action.

You can check this out https://druid.apache.org/docs/latest/development/extensions-contrib/prometheus/ .

Is this not just a way of serving the metrics that Druid already emits?