Guide: Monitoring QNAP System & CPU Temperatures in Beszel

[philipsoeberg]

When running the Beszel Agent on QNAP via Container Station, the default collector often only picks up the CPU temperature. For a NAS, monitoring the System (Motherboard/Chassis) temperature is often just as critical.

How it works
The script below runs on the QNAP host. It polls temperatures via getsysinfo QNAP host tool and writes them to /tmp/tempmonitor. By mounting this directory into the container at the standard Linux path /sys/class/hwmon/hwmon0, the agent can read the values as native hardware sensors.

1. The Bridge Script (tempmonitor.sh)
Save this script on your QNAP (e.g., /share/Public/scripts/tempmonitor.sh) and ensure it is executable (chmod +x). You can call it from your autorun.sh to ensure it starts on boot.

#!/bin/sh

# Base Directory on the host
TEMPMON_DIR="/tmp/tempmonitor"

# File paths conforming to hwmon standard
FILE_SYSTMP="$TEMPMON_DIR/temp1_input"
FILE_CPUTMP="$TEMPMON_DIR/temp2_input"

# Initialize directory
if [ ! -d "$TEMPMON_DIR" ]; then
    echo ">> Creating directory $TEMPMON_DIR"
    mkdir -p "$TEMPMON_DIR"
fi

touch "$FILE_SYSTMP" "$FILE_CPUTMP"

# Create static metadata files for discovery
# name: provides a static identifier for the sensor group
# label: defines the sensor name in the Beszel UI
echo "tempmon" > "$TEMPMON_DIR/name"

echo "100000" > "$TEMPMON_DIR/temp1_crit"
echo "systmp"  > "$TEMPMON_DIR/temp1_label"
echo "80000"   > "$TEMPMON_DIR/temp1_max"

echo "100000" > "$TEMPMON_DIR/temp2_crit"
echo "cputmp"  > "$TEMPMON_DIR/temp2_label"
echo "80000"   > "$TEMPMON_DIR/temp2_max"

cleanup() {
    echo ">> Stopping Temperature Monitor..."
    rm -f "$FILE_SYSTMP" "$FILE_CPUTMP"
    rmdir "$TEMPMON_DIR" 2>/dev/null
    exit 0
}

trap cleanup INT TERM

echo ">> Temperature Monitor Started"
echo ">> Root Directory: $TEMPMON_DIR"
echo ">> Sampling every 30 seconds..."

while true; do
    # Get values in millidegrees (standard for hwmon)
    VAL_SYS_MS=$(getsysinfo systmp | awk '{print $1 * 1000}')
    VAL_CPU_MS=$(getsysinfo cputmp | awk '{print $1 * 1000}')

    # Update files
    echo "$VAL_SYS_MS" > "$FILE_SYSTMP"
    echo "$VAL_CPU_MS" > "$FILE_CPUTMP"

    # Log readable output with directory and Celsius conversion
    echo "$(date '+%H:%M:%S') [$TEMPMON_DIR] - Updated: Sys $((VAL_SYS_MS / 1000))°C, CPU $((VAL_CPU_MS / 1000))°C"

    sleep 30
done

2. Docker Compose Configuration
In your Beszel Agent compose.yaml, map the host's /tmp/tempmonitor directory to the agent's expected sensor path.

services:
  beszel-agent:
    image: henrygd/beszel-agent:latest
    restart: unless-stopped
    network_mode: host
    volumes:
      - beszel_agent_data:/var/lib/beszel-agent
      - /var/run/docker.sock:/var/run/docker.sock:ro
      # Map the bridged sensor data to hwmon0
      - /tmp/tempmonitor:/sys/class/hwmon/hwmon0:ro
    environment:
      HUB_URL: http://<your-hub-ip>:8090
      KEY: 'your-public-key'
      # Set Primary Sensor to System Temp
      # Format: <name-file-content>_<label-file-content>
      PRIMARY_SENSOR: tempmon_systmp

[henrygd]

That's smart, thanks for sharing!