A very simple fan controller to control D51B-2U fans via the IPMI interface

Quanta_D51B-2U_IPMI_FanController.sh

#!/bin/bash

#Conor Shore 2020
#Basic Fan Control Script For Quanta D51B-2U Server via IPMI
#designed to be used in init.d

### BEGIN INIT INFO
# Provides:          IPMI Fan Controller
# Required-Start:    $all
# Required-Stop:
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Controls server fans
### END INIT INFO

#variable used for temp
cputemp=0

#the number the error will be multiplied by
factor=5

#target temp
target=40

#minimum fan level setting
minimum=11

#maximum fan level setting
maximum=100

#ip address of the IPMI interface
ipmiip="192.168.1.1"

# in brackets to run as background tax and not cause timeout
(while sleep 15
do
		#get current temps of each cpu
        cpu0=$(ipmitool -H $ipmiip -U admin -P admin sensor reading Temp_CPU0 | cut -f2 -d "|" | cut -f2 -d " ")
        cpu1=$(ipmitool -H $ipmiip -U admin -P admin sensor reading Temp_CPU1 | cut -f2 -d "|" | cut -f2 -d " ")


		#figure out which cpu is hotter
        if [ $cpu0 -gt $cpu1 ]; then
                cputemp=$cpu0
        else
                cputemp=$cpu1
        fi
		
        error=$((cputemp-target))

		#new fan speed
        newfan=$(((error*factor)+minimum))

		#bounding fanspeed to max and min
        if [ $newfan -lt $minimum ]; then
                newfan=$minimum
        fi

        if [ $newfan -gt $maximum ]; then
                newfan=$maximum
        fi

		#convert to hex
        newfanhex=$(printf "%x" $newfan)

		#issue commands
        ipmitool -H $ipmiip -U admin -P admin raw 0x30 0x39 0x01 0x0 0x0 0x$newfanhex
        ipmitool -H $ipmiip -U admin -P admin raw 0x30 0x39 0x01 0x0 0x1 0x$newfanhex
        ipmitool -H $ipmiip -U admin -P admin raw 0x30 0x39 0x01 0x0 0x2 0x$newfanhex
        ipmitool -H $ipmiip -U admin -P admin raw 0x30 0x39 0x01 0x0 0x3 0x$newfanhex

		#write to syslog what happened this time around
		logger "max cpu temp $cputemp setting fans to 0x$newfanhex"

done) &
exit 0