NUT and VMware (ESXi)

Some links to external discussions (brought up in #1956 discussion):

• https://github.com/rgc2000/NutClient-ESXi with recipe sources and binary releases of "Network UPS Tools client for VMware ESXi 5.0-8.0" (as of this writing)
  • Earlier maintained for a decade as a detailed blog at http://rene.margar.fr/2012/05/client-nut-pour-esxi-5-0/ (in French, updated occasionally with builds of newer NUT releases)
• https://serverfault.com/a/473690
  • https://pastebin.com/KkEeanK1
• https://justit.eu/quick-setup-network-ups-tools-nut-server-on-debian-10/ as referenced from https://github.com/networkupstools/nut/issues/1004#issuecomment-1661506623 (notably, the ticket discussed issues with USB pass-through with VMWare up to 7.x that seemed to go better after an upgrade to 8.x)

Generally, it can help to revise existing NUT issues and PRs labeled VMware (whether still open or already closed).

Note that meaningless data from NUT drivers were seen with virtualization and pass-through of USB devices, where NUT driver on host or guest system could not see everything, because another program (kernel handler, NUT drivers or some other programs) on the other side of the virtual border, in the guest or host system respectively, also tried to handle the device. This is not a conflict that can be always caught by either of the two kernels and virtualization layer, and each system thinks it fully owns the device, but it does lead to bogus reads. The device is typically stuck in "OB" state and does not report much otherwise (except basic connection data like the vendor and model).