Ghetto fan control script for Dell PowerEdge servers

ghetto_fan_control.sh

#!/usr/bin/env bash
set -euo pipefail

# NOTE: Based on this: https://github.com/NoLooseEnds/Scripts/blob/master/R710-IPMI-TEMP/R710-IPMITemp.sh
# NOTE: Read more: https://www.spxlabs.com/blog/2019/3/16/silence-your-dell-poweredge-server

readonly IPMI_HOST=127.0.0.1
readonly IPMI_USER=root
readonly IPMI_PASSWORD=calvin
readonly IPMI_ENCRYPTION_KEY=0000000000000000000000000000000000000000

readonly HEALTHCHECKSIO_URL=<URL>

readonly AUTO_FALLBACK_TEMP=60
readonly MANUAL_ENABLE_TEMP=40
readonly SLEEP_SECONDS=60


# NOTE: Alternative, more secure approach. Only works if running from the same host.
function run_ipmi_command {
        if ! test "$#" -gt 0; then
                >&2 echo '---(X) Usage: run_ipmi_command ARGS ...'
                exit 1
        fi

        ipmitool $@
}


function run_ipmi_command_over_ip {
        if ! test "$#" -gt 0; then
                >&2 echo '---(X) Usage: run_ipmi_command ARGS ...'
                exit 1
        fi

        ipmitool \
                -I lanplus \
                -H "${IPMI_HOST}" \
                -U "${IPMI_USER}" \
                -P "${IPMI_PASSWORD}" \
                -y "${IPMI_ENCRYPTION_KEY}" \
                $@
}


function disable_manual_fan_control {
        run_ipmi_command raw 0x30 0x30 0x01 0x01
        >&2 echo '---(i) INFO: Disabled manual fan control'
}


function enable_manual_fan_control {
        run_ipmi_command_over_ip raw 0x30 0x30 0x01 0x00

        run_ipmi_command_over_ip raw 0x30 0x30 0x02 0xff 0x05 # 5%
        #run_ipmi_command_over_ip raw 0x30 0x30 0x02 0xff 0x0A  # 10%

        >&2 echo '---(i) INFO: Enabled manual fan control with 5% offset'
}


function main {
        enable_manual_fan_control

        while true; do
                local current_temp
                current_temp="$(
                        run_ipmi_command_over_ip sdr type temperature | \
                        cut -f5 -d'|' | \
                        awk '{ print $1 }' | \
                        sort -r | \
                        head -n1
                )"

                >&2 echo "---(i) INFO: Retrieved current temperature: ${current_temp}"

                if test "${current_temp}" -ge "${AUTO_FALLBACK_TEMP}"; then
                        >&2 echo '---(!) WARNING: Current temperature is too high, disabling manual fan control'
                        disable_manual_fan_control
                elif test "${current_temp}" -le "${MANUAL_ENABLE_TEMP}"; then
                        >&2 echo '---(i) INFO: Current temperature is normalised, enabled manual fan control'
                        enable_manual_fan_control
                fi

                local healthcheckio_resp="$(curl -s "${HEALTHCHECKSIO_URL}")"
                >&2 echo "---(i) INFO: Pinged HealthCheckIO: ${healthcheckio_resp}"

                >&2 echo "---(+) OK: Finished iteration, sleeping for ${SLEEP_SECONDS}"
                sleep "${SLEEP_SECONDS}"
        done
}


main "$@"