Want to run oximeter in standalone mode

[bnaecker]

Running oximeter currently requires nearly the entire control plane. In addition to oximeter itself, one needs nexus to assign metric producers to collectors; CockroachDB to record that assignment; and ClickHouse for oximeter to insert data. This is all pretty heavyweight, especially if one wants to test just things like the basic accuracy of the metrics collected by oximeter.

It would be very helpful to have an oximeter-standalone binary. This would run the collector more or less as usual, but without any of the other components. It could be pointed directly at a producer; collect its metrics periodically; and simply print them. The oximeter-client may be useful here, or we could just start up a binary with the producer's endpoint directly.

A slightly more full-featured version might tell oximeter-standalone how to reach ClickHouse, in which case data would be inserted into the database as well. This might be useful for developing query tools, for example.

[jordanhendricks]

This would be great! I really wanted to be able to do this when I was reproducing and testing the fix for oxidecomputer/propolis#497.

[bnaecker]

Closed by #4117