I already had a look at both articles before asking here.
The problem is not the http interface which works fine (the /cloud/server_status is only available on the http interface and not on the console proxy).
Duncan (YB) sugests to use the /sdk/vimServiceVersions.xml but it does not work at least no on my F5 systems and Christian (edge-cloud) uses a simple tcp check which has the downsides I just mentioned above: log polution and improper health detection.