Blackbox Lite

A comprehensive Bash script that monitors websites and VM hosts, collecting metrics in Prometheus format for integration with Node Exporter's textfile collector. This tool provides real-time monitoring of website availability, SSL certificate health, response times, and VM host connectivity.

Features

Website Monitoring

• Availability Check: Monitors website uptime with HTTP status code validation
• Response Time: Measures website response time in seconds
• SSL Certificate Monitoring:
  • Validates SSL certificate validity
  • Tracks days until certificate expiration
  • Detects TLS version in use
• HTTP Status Codes: Captures and reports HTTP response codes
• Follow Redirects: Automatically follows HTTP redirects (3xx)

VM Host Monitoring

• Ping Connectivity: Tests host reachability using ICMP ping
• Response Time: Measures average ping response time

Additional Features

• Prometheus-Compatible: Outputs metrics in standard Prometheus textfile format
• Atomic Writes: Uses temporary files for safe metric updates
• Error Handling: Graceful error handling and dependency checking
• Metadata Metrics: Includes monitoring run timestamps and target counts

Required Dependencies

The script automatically checks for and requires the following tools:

• curl: For HTTP/HTTPS website checks
• openssl: For SSL certificate validation and TLS version detection
• ping: For VM host connectivity testing
• bc: For mathematical calculations (response time conversions)

Configuration

Customizing Websites to Monitor

Edit the WEBSITES array in the script

WEBSITES=(
    "https://example.com"
    "https://api.example.com"
    "http://internal.example.com"
    "https://example.com/specific/endpoint"
)

Customizing VM Hosts to Monitor

Edit the VM_HOSTS array in the script (lines 21-39):

VM_HOSTS=(
    "server1.example.com"
    "192.168.1.100"
    "api-server.internal"
)

Changing Output Path

Modify the TEXTFILE_PATH variable (line 7) to match your Node Exporter configuration:

TEXTFILE_PATH="/opt/node_exporter/textfile_collector/combined_monitor.prom"

Usage

Manual Execution

Run the script manually:

./monitor.sh

Scheduled Execution with Cron

Add to crontab for automated monitoring (runs every 5 minutes):

crontab -e

Add the following line:

*/5 * * * * /path/to/monitor.sh >/dev/null 2>&1

Or for more frequent monitoring (every minute):

* * * * * /path/to/monitor.sh >/dev/null 2>&1

Integration with Prometheus

Node Exporter Configuration

1. Install Node Exporter (if not already installed)
2. Configure Node Exporter to use the textfile collector:    Edit /etc/systemd/system/node_exporter.service or your Node Exporter configuration:

   [Service]
   ExecStart=/usr/local/bin/node_exporter \
       --collector.textfile.directory=/opt/node_exporter/textfile_collector \
       --collector.textfile

3. Verify metrics are being collected:

   curl http://localhost:9100/metrics | grep website_
   curl http://localhost:9100/metrics | grep vm_host_

Examples Output

Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.