[Xymon] Monitoring ESXi 6.x cpu, disk, memory, procs?

[Guy]

Does anyone have a simple example of how to monitor the usual client
stuff on an ESXi host?

I was thinking it should be possible for the Xymon server to reach out
via SSH, run some commands (esxcli?) and return the output. If the
response is null or ssh connection failed, report red.

Another thought, /bin/python3.5 is available on ESXi - so perhaps
there's a way to run and report the tests with python on the ESXi host
itself as a cronjob?

My coding skills are still a work in progress so any examples of how
to accomplish something like this would be helpful. The list archives
reference a lot of old scripts and code for ESXi 4/5 which don't seem
to work for ESXi 6.5+

Thanks,

Guy