SNMP

use your choice of snmp scraping tool

interfacing with snmp is very standard and has been for the past 2 decades

snmpwalk if you're poking at it from the shell

librenms, observium, nagios, and zabbix have existed for the past 1-2 decades too

personally librenms is the best option for just network devices and server IPMI SNMP

just slap as many snmp scrapers into the network

keep the interval reasonable though

1 minute or 30 seconds

PDU

yeah. same community of "public" applies for poking it