Julien

Not sure how we could do it as the EC2 Api only returns one address https://docs.aws.amazon.com/sdk-for-go/api/service/ec2/#Instance

We could use InstanceNetworkInterface at the expense of extra API calls

I think the last test is wrong and should error. We might just call String() to compare the regexes.

OK, let's move forward with this.

This indeed does not belong to the discovery manager but to the scrape manager.

Why can't we use the TSDB like we do for the alerts timestamps?

I would be in favour of maybe adding a 'last failure' in the UI.

First step is adding that to the API then: #7797

Is that a dupe of #2615 somehow?

Thank you for this detailed report. The Prometheus openmetrics parser is optimized for performance rather than correctness. It is not "OpenMetrics compatible" in the sense of rejecting every bad exposition...