Monitors the VMware vCenter Server Appliance (VCSA) itself via its REST API. Detects vMon service failures, appliance health issues, high CPU, memory, swap and filesystem usage, pending updates, failed backups and expiring certificates. Tested on VCSA 7.x and 8.x, designed for 9.x. Based on https://exchange.checkmk.com/p/vcsa7-health-status