Track any shared CPU amongst neighbors (useful to detect oversold CPU VMs on Cloud providers)

cpu_steals.md

Great! Let’s set up the monitoring and logging step by step. I’ll guide you through the process.

Step 1: Install Necessary Tools

We need to install mpstat (from the sysstat package) for monitoring CPU steal time and vnstat for bandwidth monitoring.

1. Install sysstat for mpstat: Run the following command based on your Linux distribution:

   For Ubuntu/Debian:

   sudo apt-get install sysstat

   For CentOS/RHEL:

   sudo yum install sysstat

2. Install vnstat: Similarly, install vnstat:

   For Ubuntu/Debian:

   sudo apt-get install vnstat

   For CentOS/RHEL:

   sudo yum install vnstat

---

Step 2: Create CPU Steal Monitoring Script

1. Create the script to monitor CPU steal time.

   Open your preferred text editor to create the script:

   nano /home/user/check_cpu_steal.sh

2. Add the following code to check CPU steal time and log it:

   #!/bin/bash
   
   # Get the current date and time
   DATE=$(date "+%Y-%m-%d %H:%M:%S")
   
   # Get the CPU steal time using mpstat
   STEAL=$(mpstat -P ALL 1 1 | grep "all" | awk '{print $11}')
   
   # Log the result into a log file
   echo "$DATE - CPU Steal: $STEAL%" >> /var/log/cpu_steal.log

3. Make the script executable:

   chmod +x /home/user/check_cpu_steal.sh

---

Step 3: Create Bandwidth Monitoring Script

1. Create the script to monitor bandwidth usage:

   Open your text editor to create the script:

   nano /home/user/check_bandwidth.sh

2. Add the following code to monitor bandwidth usage and log it:

   #!/bin/bash
   
   # Get the current date and time
   DATE=$(date "+%Y-%m-%d %H:%M:%S")
   
   # Get the bandwidth usage from vnstat
   BANDWIDTH=$(vnstat -i eth0 --oneline | awk -F ';' '{print $9}')
   
   # Log the result into a log file
   echo "$DATE - Bandwidth: $BANDWIDTH" >> /var/log/bandwidth.log

   Note: Replace eth0 with your actual network interface name if it’s different (you can check it by running ip a).

3. Make the script executable:

   chmod +x /home/user/check_bandwidth.sh

---

Step 4: Set Up Cron Jobs

1. Edit your crontab file to run the scripts every minute:

   crontab -e

2. Add the following lines at the bottom of the crontab file to run the scripts every minute:

   * * * * * /home/user/check_cpu_steal.sh
   * * * * * /home/user/check_bandwidth.sh

   This will execute both scripts every minute and log the results.

---

Step 5: Check the Logs

1. Check the CPU steal log:

   You can check the cpu_steal.log file by running:

   tail -f /var/log/cpu_steal.log

2. Check the bandwidth log:

   Similarly, check the bandwidth.log file:

   tail -f /var/log/bandwidth.log

   This will show real-time updates of the logs.

---

Optional: Set Up Alerts (Optional)

If you'd like to be alerted when the CPU steal time exceeds a certain threshold, you can add an email notification to your CPU script.

For example, if you want to send an email when CPU steal time is more than 5%, modify your CPU script like this:

1. Open your check_cpu_steal.sh script:

   nano /home/user/check_cpu_steal.sh

2. Add the alert logic just before the echo statement:

   # Send an email alert if CPU steal time is more than 5%
   if (( $(echo "$STEAL > 5" | bc -l) )); then
       echo "High CPU Steal: $STEAL%" | mail -s "CPU Steal Alert" [email protected]
   fi

   You’ll need to have a working mail service set up on your server for this to work (like sendmail or postfix).

---

Step 6: Verify Everything Works

Once everything is set up:

1. Wait a minute or so for the cron jobs to run.
2. Check the logs by using tail:

   tail -f /var/log/cpu_steal.log
   tail -f /var/log/bandwidth.log

You should see entries like:

2025-02-25 14:01:01 - CPU Steal: 0.05%
2025-02-25 14:01:01 - Bandwidth: 1.5GB

---

Done! 🎉

You now have a system that logs both CPU steal time and bandwidth usage on a regular basis. If you set up email alerts, you will be notified if the CPU steal time exceeds a threshold.

other options

• YABS: https://github.com/masonr/yet-another-bench-script
• nench aka bench: https://github.com/n-st/nench
• list: https://monovm.com/blog/vps-benchmark-tools/
• https://serverscope.io/run-benchmark