GCP Idle VM Shutdown Script

gcp_idle_vm.sh

#!/bin/bash
# Add this script to instance metadata and reboot
# gcloud compute instances add-metadata INSTANCE_NAME --metadata-from-file startup-script=gcp_idle_vm.sh
# To follow logs sudo journalctl -f -u google-startup-scripts.service
# For this to work ensure your vm is private or has appropriate firewall rules
# otherwise brute force attacks will keep your vm alive

has_connection_existed=false
idle_count=0

while true; do
  is_ssh_connected=false

  # This command won't work because vscode connections
  # don't always show up here
  # who -u | grep -q jaden && is_ssh_connected=true

  # Check if there are any active SSH connections
  ss -a -e | grep ssh | grep ESTAB && is_ssh_connected=true

  echo "SSH connected: $is_ssh_connected"

  if ! $is_ssh_connected; then
    # If all ssh connections have been closed, shut down the VM
    # Only after the first initial connection has been made
    if $has_connection_existed; then
      idle_count=$((idle_count + 1))

      echo "SSH connections have been idle for $idle_count minutes"

      if [ $idle_count -gt 5 ]; then
        echo "SSH connections have been idle for 5 minutes. Shutting down..."

        sudo poweroff
      fi
    else
      echo "No SSH connection has been made yet. Waiting..."
    fi
  else
    has_connection_existed=true
    idle_count=0

    echo "SSH sessions are active. Waiting..."
  fi

  sleep 60
done