Server Status over HTTP HEAD

Overview

Server Status over HTTP HEAD, a.k.a. SSoHH, is a simple servers monitoring solution based on HTTP HEAD request. It uses a client-server architecture:

• Client - Send its status information as User Agent string in HTTP HEAD requests to the server
• Server - Parse web server log (Nginx) to extract the status information, and present on a web page

Usage

Configuration

In client_set.sh file:

property	meaning
SSOHH_TAG	Private tag in requests for identify the clients
ENDPOINT	Web server endpoint receives requests
INTERVAL	Interval in minutes (default 5) between each request

In reducer.py file:

property	meaning
config_tag	Should be consistent with SSOHH_TAG in client_set.sh
config_log_path	Absolute path of access.log logs requests from clients
config_page_path	Absolute path of the generated web page

Client-Side

Copy configured client_set.sh to each *nix machine to be monitored, chmod +x client_set.sh to make it executable. And then execute one of the following commands according to their environment:

• ./client_set.sh pi for Raspbian on Raspberry Pi
• ./client_set.sh bbb for Debian on BeagleBone Black
• ./client_set.sh linux for Ubuntu Linux
• ./client_set.sh mac for OS X on Macintosh

You may add/edit MONITOR in client_set.sh to customize the metrics. Sections in MONITOR should match the regular expression \[(?P<key>.*?)\](?P<value>.*?);. And this regular expression can also be customized by changing section_pattern in reducer.py.

Server-Side

Ensure reducer.py and template.html are configured and in the same directory, add the following line to crontab:

* * * * * (sleep 10; python3 /your/path/to/ssohh/reducer.py)

Start the web server to host the generated page, and open your browser to visit it. (You may need to execute the script manually if it hasn't been executed by crontab yet.)

Preview

Suggestion

1. Keep SSOHH_TAG confidential if you don't want to see any faked lines
2. Use exclusive web server endpoint and access.log for SSoHH

Known Issues

1. Not supported on Microsoft Windows Server
2. Log rotation may cause missing lines on the page, especially for machines that have been disconnected for a while
3. hostname is the only identification for each machine, duplicate or modification will cause missing/additional lines on the page