Tailscale Status Monitor & Telegram Alerter

A lightweight Bash script designed for Linux environments (Ubuntu/Alpine/LXC) to monitor the Tailscale backend state and send real-time alerts via Telegram when a node requires re-authentication or goes offline.

🚀 Features

• Real-time Monitoring: Detects if Tailscale is Running, NeedsLogin, or Stopped.
• Reliable Parsing: Uses jq for accurate JSON data extraction.
• Smart Notifications: Sends formatted Telegram alerts including Hostname and Timestamp.
• LXC/Docker Compatible: Works within Proxmox containers and virtual machines.

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🛠️ Prerequisites

1. Tailscale installed and configured.
2. jq installed (for JSON parsing):
   • Ubuntu/Debian: sudo apt update && sudo apt install jq -y
   • Alpine: apk add jq
3. curl installed (for sending Telegram messages).

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🤖 Telegram Bot Setup

To send notifications, you need a Telegram Bot and your personal Chat ID.

1. Create the Bot

1. Search for @BotFather on Telegram.
2. Send /newbot and follow the instructions to name your bot.
3. Save the API Token provided (e.g., 12345678:AAH...).

2. Get Your Chat ID

1. Search for your new bot's username and press Start.
2. Visit the following URL in your browser (replace YOUR_TOKEN with your API Token): https://api.telegram.org/botYOUR_TOKEN/getUpdates
3. Look for "id": in the JSON response (e.g., 987654321). This is your Chat ID.
   • Note: If sending to a group, add the bot to the group and use a bot like @IDBot to get the group ID (it will start with a -).

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📥 Installation

1. Create the script file:

   sudo nano /usr/local/bin/tailscale-monitor.sh
   

2. Make it executable:

   sudo chmod +x /usr/local/bin/tailscale-monitor.sh
   

Automation (Cron Job)

1. Make it executable: To monitor Tailscale automatically every 5 minutes:

   crontab -e
   

2. Add the following line at the bottom:

*/5 * * * * /usr/local/bin/tailscale-monitor.sh > /dev/null 2>&1