add service and script, update readme

README.md

@@ -55,3 +55,28 @@ Date 04-09-2020 10:24:52
 --> Setting fan speed to 20%
 ```
 Once you have verified the script is working you can set it to run every 5 minuites via cron. On TrueNAS this can be found under the Tasks menu --> Cron Jobs.
+
+##Running as a service
+
+Once the service is up and running, the temprature will be checked every `INTERVAL_SEC` seconds. Fan speed will change if the temprature has changed and warrants a speed change. 
+
+There is a delay before the temprature monitoring begins and is controlled by the variable `INITIAL_START_DELAY_SEC`. After this initial delay the time between checks is governed by the `INTERVAL_SEC` value.
+
+When the server is shutdown/rebooted or started, the manual control is reset, this is to avoid any left over low fan speeds from previous power outage/powerdown/shutdown etc.
+
+The files required to run the service are `fan_control_dyn.sh` `fancontrol.service`
+
+
+Simply execute the following to get the service set up.
+```
+sudo cp fan_control_dyn.sh /usr/local/sbin/fan_control_dyn.sh
+sudo chmod 755 /usr/local/sbin/fan_control_dyn.sh
+sudo cp fancontrol.service /etc/systemd/system/fancontrol.service
+sudo systemctl enable fancontrol.service
+sudo systemctl start fancontrol.service
+```
+
+If you are using a location other than `/usr/local/sbin/fan_control_dyn.sh` then you'll need to modify the location in the `fancontrol.service` file as well 
+```
+ExecStart=/MY_ABSOLUTE_PATH/fan_control_dyn.sh
+```

fan_control_dyn.sh

@@ -0,0 +1,84 @@
+#!/bin/bash
+
+# Variables
+IDRAC_IP="IP address of iDRAC"
+IDRAC_USER="user"
+IDRAC_PASSWORD="passowrd"
+INTERVAL_SEC=5
+INITIAL_START_DELAY_SEC=60
+
+TEMP_THRESHOLD=35
+TEMP_SENSOR="04h"   # Inlet Temp
+#TEMP_SENSOR="01h"  # Exhaust Temp
+#TEMP_SENSOR="0Eh"  # CPU 1 Temp
+#TEMP_SENSOR="0Fh"  # CPU 2 Temp
+
+FCTRL=0 #disabled, enabled=1
+LAST_PCT=0
+
+
+toggle() {
+    ipmitool -I lanplus -H $IDRAC_IP -U $IDRAC_USER -P $IDRAC_PASSWORD raw 0x30 0x30 0x01 $1 2>&1 >/dev/null
+}
+
+reset_manual() {
+    toggle 0x01
+    FCTRL=0 #disabled
+}
+
+set_manual() {
+    toggle 0x00
+    FCTRL=1 #enabled
+}
+
+graceful_exit() {
+    reset_manual
+    exit 0
+}
+
+trap graceful_exit SIGINT SIGTERM
+
+
+# need the reset in case the system boots up with the last set value
+reset_manual
+
+#start delay
+sleep $INITIAL_START_DELAY_SEC
+
+
+while [ 1 ]
+do
+
+    # Get temperature from iDARC.
+    T=$(ipmitool -I lanplus -H $IDRAC_IP -U $IDRAC_USER -P $IDRAC_PASSWORD sdr type temperature 2>/dev/null | grep $TEMP_SENSOR | cut -d"|" -f5 | cut -d" " -f2)
+
+    # If ambient temperature is above 35deg C enable dynamic control and exit, if below set manual control.
+    if [[ $T -ge $TEMP_THRESHOLD ]]
+    then
+        if [[ $FCTRL -ne 0 ]]
+        then
+            reset_manual
+        fi
+    else
+        
+        # This gives a Percent that is a multiple of 5 for ranges of 5 degC
+        PCT=$(( 5 * ( T / 5 ) ))
+        # Min PCT Allowed is 10
+        PCT=$(( PCT < 10 ? 10 : PCT ))
+        
+
+        if [[ $LAST_PCT -ne $PCT ]]
+        then
+            if [[ $FCTRL -eq 0 ]]
+            then
+                set_manual
+            fi
+            PCTHEX=$(printf '0x%02x' $PCT)
+            ipmitool -I lanplus -H $IDRAC_IP -U $IDRAC_USER -P $IDRAC_PASSWORD raw 0x30 0x30 0x02 0xff $PCTHEX 2>&1 >/dev/null
+            LAST_PCT=$PCT
+        fi
+    fi
+
+    
+    sleep $INTERVAL_SEC
+done

fancontrol.service

@@ -0,0 +1,20 @@
+[Unit]
+Description=Fan Control script
+
+StartLimitIntervalSec=14400
+StartLimitBurst=10
+
+[Service]
+Restart=on-abnormal
+
+User=root
+Group=root
+
+ExecStart=/usr/local/sbin/fan_control_dyn.sh
+
+ProtectSystem=full
+
+TimeoutStopSec=5s
+
+[Install]
+WantedBy=multi-user.target