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Linux Open File Descriptor Watchdog
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| #!/bin/bash | |
| # =============================================================== | |
| # Open File Descriptor Watchdog | |
| # =============================================================== | |
| # | |
| # This script monitors the number of open file descriptors (FDs) | |
| # per process on a Linux server. If any process exceeds the | |
| # defined threshold, it sends a Telegram alert with process info. | |
| # | |
| # --------------------- | |
| # Configuration | |
| # --------------------- | |
| # 1. Set your Telegram bot ID and token below. | |
| # 2. Set the FD usage threshold below (default is 100). | |
| # | |
| # --------------------- | |
| # Install cronjob | |
| # --------------------- | |
| # Run every 15 minutes: | |
| # */15 * * * * /path/to/fd_watchdog.sh | |
| # | |
| # Make sure the script is executable: | |
| # chmod +x /path/to/fd_watchdog.sh | |
| # | |
| # =============================================================== | |
| # ================ | |
| # Config | |
| # ================ | |
| THRESHOLD=5000 | |
| DATE=$(date "+%Y-%m-%d %H:%M:%S") | |
| TG_BOT_ID="your_bot_id_here" # Only the numeric ID (e.g., 123456789) | |
| TG_BOT_TOKEN="your_bot_token_here" # Full token from BotFather | |
| # ================ | |
| # URL encode helper | |
| # ================ | |
| urlencode() { | |
| local LANG=C | |
| local length="${#1}" | |
| for (( i = 0; i < length; i++ )); do | |
| local c="${1:i:1}" | |
| case $c in | |
| [a-zA-Z0-9.~_-]) printf "$c" ;; | |
| *) printf '%%%02X' "'$c" ;; | |
| esac | |
| done | |
| } | |
| # ================ | |
| # Telegram function | |
| # ================ | |
| send_telegram_message() { | |
| local message="$1" | |
| local message_encoded=$(urlencode "$message") | |
| curl -s -o /dev/null --max-time 5 \ | |
| "https://api.telegram.org/bot$TG_BOT_ID:$TG_BOT_TOKEN/sendMessage?chat_id=-156311897&text=$message_encoded" | |
| } | |
| # ================ | |
| # Watchdog logic | |
| # ================ | |
| lsof -nP | awk '{print $2}' | sort | uniq -c | while read count pid; do | |
| if [[ "$count" -gt "$THRESHOLD" ]]; then | |
| cmd=$(ps -p "$pid" -o comm= 2>/dev/null) | |
| if [ -n "$cmd" ]; then | |
| message="! $DATE - PID $pid ($cmd) is using $count FDs (threshold: $THRESHOLD)" | |
| send_telegram_message "$message" | |
| fi | |
| fi | |
| done |
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