CPU temperature command, Kg key for IPMIv2 authentication, RPi Service and Additional Speeds/Temps

Hi there! So this tool has been great but I had to make a few tweaks to get it to work and while I was at it I improved a bit as well(at least I think so). I wanted to share my process to get this to work on a Raspberry Pi 4b host running Raspberry Pi OS to control a Dell Poweredge R710 running Proxmox 7.1-12.

First Proxmox would not show cpu values from the suggested "sysctl -a" command. Instead I needed to install im-sensors on the Dell server and run "sensors -u" through ssh. The entire command being:

ssh root@dell_hostname 'sensors -u | grep input | grep -E -o "[0-9]+\.[0-9]+"'

Next the ipmitool would not work and would return an error: "RAKR 4 message has invalid integrity check value". No matter where I looked I could not find this specific error, at least nothing that wasn't behind a paywall. I then came across a different tutorial here: https://jacobjangles.com/hushing-the-dell-r710-fans/ that had an additional flag on the ipmitool. After looking into it, it made sense that I needed to define the Kg key using the "-y " flag. So adding that flag and hex key to the config file and subprocess.check_output allowed the commands to go through.

    cmd = ["ipmitool"]
    if state[host['name']]['is_remote']:
        cmd += ['-I', 'lanplus']
        cmd += ['-H', host['remote_ipmi_credentials']['host']]
        cmd += ['-U', host['remote_ipmi_credentials']['username']]
        cmd += ['-P', host['remote_ipmi_credentials']['password']]
        cmd += ['-y', host['remote_ipmi_credentials']['hexkey']]
    cmd += (args.split(' '))

The last issue that I had while running this was that because Raspberry Pi OS runs the systemctl service as root the service would fail. I needed to add both "User=pi" and "WorkingDirectory=/opt/fan_control" to the /etc/systemd/system/fan-control.service to get it to work after that.

[Unit]
Description=Temperature-based fan speed controller
After=network.target

[Service]
User=pi
Type=simple
WorkingDirectory=/opt/fan_control
ExecStart=/opt/fan_control/venv/bin/python3 -u /opt/fan_control/fan_control.py
Restart=always
RestartSec=15

[Install]
WantedBy=multi-user.target

Then I ran the following for the change to take effect:

sudo systemctl daemon-reload
sudo systemctl enable fan-control.service
sudo systemctl start fan-control.service

Once I got the tool running I updated it to use some recommended commands for Python3 and changed it to use more speed/temp combos.

I saw it is recommended now to use "subprocess.run" instead of "subprocess.check_output", but I am not sure the difference or why. I update it though which makes line 41 of fan_control.py:

subprocess.run(cmd, check=True, capture_output=True, text=True)

There is also a hex conversion in python that simplified some of the code on line 74:

        wanted_percentage_hex = hex(wanted_percentage)

For my own use case I also included another command to get the ambient temperature from the Dell server just to help average the temperature for the entire server using the following command:

ipmitool -I lanplus -H idrac_hostname -U ipmi-user -P password -y hex_key sdr type temperature | grep Ambient | grep -Po '\| ([0-9]+) degrees' | grep -Po '[0-9]+'

The last change I made was adding a for loop for temp/speed checks instead of a set 3. Just so I could have a finer control over the speeds. So after removing lines 107-110 I updated the code originally on lines 172-195 to the following:

    for idx, x in enumerate(host['temperatures']):
        idx_under = idx - 1
        idx_over = idx + 1
        if idx == 0:
            if (
                temp_average <= x and
                checkHysteresis(temp_average, idx, host)
            ):
                set_fan_speed(idx, host)
                return True
        elif idx_over == len(host['temperatures']):
            if x < temp_average:
                set_fan_control("automatic", host)
                return True
        elif (
            host['temperatures'][idx_under] < temp_average <= x and
            checkHysteresis(temp_average, idx_under, host)
        ):
            set_fan_speed(idx_under, host)
            return True
        elif (
            x < temp_average <= host['temperatures'][idx_over] and
            checkHysteresis(temp_average, idx, host)
        ):
            set_fan_speed(idx, host)
            return True

I know this may not be the best way to do this and I am not an expert in Python but maybe it will help someone else or help improve the development of the tool as it really has been great so far!

nmaggioni / r710-fan-controller

CPU temperature command, Kg key for IPMIv2 authentication, RPi Service and Additional Speeds/Temps #11