going back to this thread of last week, to summarize if it helps some:
• one needs the FR agent within the jvm (so implemented "inside" CF or Lucee or a container instance for them). As noted, other java apm's work this way, to get info available only "from within" the jvm
• that FR agent happens to also (by default) expose a web web server (port 8088, by default), which offers the traditional FR UI (now called the "on-prem" ui). this part may be less common with other APMs, and of course it's ephemeral: goes away with a container stop (and the data it tracked goes away with an instance stop)
• even before discussing FR Cloud, note also that FR also logs a tremendous amount of info. That can be viewed across restarts, of course, which can be pushed to a logging solution, or with containers can at least be pushed to a more persistent volume
• And since FR 7.2, the on-prem UI alone has offered "metrics>archive metrics", which can graph and view those logs--and you can tell it where to find those, but it presumes a traditional location within an on-prem folder
• Then in the past few years, FR Cloud has come along and offers what Mikey and others refer to: pushing the metrics (and soon, the logs) out of the FR instance and up to the cloud, which offers its OWN (different) UI. The FR folks manage that FR cloud instance (and datastore), but it's secure and can be made still more secure with obfuscation, or the push to it can be disabled.
• There's also plans afoot to allow a local deployment of that, for those who cannot push info to the cloud, but want that whose experience in their network but off the instance/container
• Hope that helps