How to Set Up an Auto Reboot Script for CPU and RAM Monitoring on Raspberry Pi - Gadget Pi

This tutorial will guide you through setting up a script that automatically reboots your Raspberry Pi if the CPU load exceeds 90% or RAM usage exceeds 80%.

Prerequisites

• A Raspberry Pi.
• Raspbian OS installed.
• Basic knowledge of using the terminal.

Step 1: Install Required Tools

Open the terminal and run the following commands to update your package list and install the necessary tools:

sudo apt-get update
sudo apt-get install stress

`stress` is a tool we’ll use later to test high CPU and RAM usage.

Step 2: Create the Monitoring Script

1. Open a terminal on your Raspberry Pi.
2. Create the script file in the /usr/local/bin directory:

   sudo nano /usr/local/bin/cpu_ram_monitor.sh

3. Paste the following script into the editor:

   #!/bin/bash
   CPU_THRESHOLD=90 # CPU load threshold (%)
   RAM_THRESHOLD=80 # RAM usage threshold (%)
   
   while true; do
     CPU_LOAD=$(uptime | awk -F '[, ]+' '{print $10}' | sed 's/,//')
     RAM_USAGE=$(free | grep Mem | awk '{print $3/$2 * 100.0}' | awk '{printf "%.0f\n", $1}')
     
     echo "Current CPU Load: $CPU_LOAD%"
     echo "Current RAM Usage: $RAM_USAGE%"
     
     if (( $(echo "$CPU_LOAD >= $CPU_THRESHOLD" | bc -l) )); then
       echo "High CPU load detected: $CPU_LOAD%. Restarting..."
       sudo reboot
     fi
     
     if (( $(echo "$RAM_USAGE >= $RAM_THRESHOLD" | bc -l) )); then
       echo "High RAM usage detected: $RAM_USAGE%. Restarting..."
       sudo reboot
     fi
     
     sleep 1 # Check every second
   done
   

4. Save the file:
   • Press CTRL + X, then Y, and hit Enter to save the changes.

Step 3: Make the Script Executable

To allow the system to run the script, make it executable with this command:

sudo chmod +x /usr/local/bin/cpu_ram_monitor.sh

Step 4: Set the Script to Run at Startup

To ensure the script runs whenever your Raspberry Pi boots up, you can create a systemd service file.

1. Create the service file:

   sudo nano /etc/systemd/system/cpu_ram_monitor.service

2. Add the following content to the file:

   [Unit]
   Description=CPU and RAM Monitor Script
   After=network.target
   
   [Service]
   ExecStart=/usr/local/bin/cpu_ram_monitor.sh
   Restart=always
   
   [Install]
   WantedBy=multi-user.target
   

3. Save and close the file:
   • Press CTRL + X, then Y, and hit Enter.
4. Enable the service so it starts automatically at boot:

   sudo systemctl enable cpu_ram_monitor.service

5. Start the service immediately (without rebooting):

   sudo systemctl start cpu_ram_monitor.service

6. Verify the service is running:

   sudo systemctl status cpu_ram_monitor.service

Step 5: Test the Script

You can test if the script works by creating high CPU and RAM usage. For example: To stress the RAM:

stress --vm 1 --vm-bytes 1.7G --timeout 60

Or to simulate high web traffic load:

ab -n 1000 -c 25 https://yourdomain.com/

Verify the Reboot

After running these tests, check if the system has rebooted by using the following command:

uptime

Additionally, you can inspect the system logs to see reboot-related messages:

sudo dmesg | tail -n 20

Or:

cat /var/log/syslog | grep reboot

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This guide provides an automated monitoring and restart mechanism for your Raspberry Pi, ensuring stability under high resource loads.