[notacoward]

Multi-tenancy is something that shouldn't be underestimated. A lot of people think it's just a checklist item until (a) they need it or (b) they try to implement it in an existing system. Kudos for making it a day-one feature.

[vladvasiliu]

While I agree with your point in the general case, would you mind elaborating on the specific case of Prometheus?

My understanding is that the recommended best-practice for Prometheus is to deploy as many of them as necessary, as close to the monitored infrastructure as possible.

What use case would require deploying a single Mimir, so supposedly Prometheus (cluster) in the case of serving multiple tenants? Why not just deploy a dedicated Prometheus / Mimir stack per client?

[notacoward]

I don't know Prometheus, but I would imagine the answer depends on just how many clients you have. Probably doesn't matter if you're talking just a few. If it's a lot, then separate instances can be very expensive in terms of operational complexity and waste due to resource fragmentation. Multi-tenancy is good for bringing both of those back under control. Is there something about Prometheus that would negate that?

[vladvasiliu]

For one, it doesn't really support authentication (although it's on the roadmap).

I'm no Prometheus expert, but since you're pretty much expected to be running a bunch of servers anyway, the operational complexity has to be handled even for just one client.

You do have a point on resource fragmentation, but IME Prometheus' resource usage is fairly predictable, so you could probably mitigate that to a point.