firedown - file-based (remote) shutdown

firedown is a command line tool (written in Ruby) that enables a remote shutdown of a Linux system via Dropbox or other file synchronization services.

firedown monitors a specified directory (or several directories) on the system for the presence of a trigger file or directory. If a trigger is found, firedown issues a shutdown.

The monitored directory might be synchronized via remote services like Dropbox, thus enabling a remotely triggered shutdown of the system.

Usage

Set up firedown:

1. Schedule a cron job on the machine(s) you might want to bring down remotely, specifying the directories that should be monitored (root privileges are needed).

   For example, to check every minute for the trigger file, include a line similar to this in /etc/crontab:

   * *   * * *   root   firedown -l /path/to/monitored/directory
   

2. Alternatively, start firedown as a daemon process (again with root privileges):

   firedown --daemon /path/to/monitored/directory
   

   (Depending on the search path for root on your machine and on how you installed firedown, you might need to invoke firedown using its full path.)

Bring down the system by creating firedown.host as empty trigger file or as empty directory in any of the monitored directories, where host is the hostname of the system you want to bring down. (With Dropbox this can be done over the web interface.)

As soon as a trigger file is detected in any of the monitored directories, a shutdown with a delay of 60 seconds will be issued. To prevent shutdowns from being triggered repeatedly by the same file, the system will only be brought down when the trigger previously has been removed successfully.

If run as a daemon, firedown writes messages to /var/log/firedown.log. In non-daemon mode use the --log or -l option to write messages to the log file instead of stderr.

You can set the logging level (warn, info, or debug) with e.g. --logging-level debug (the default is info). In daemon mode, you can toggle to debug level and back by sending the SIGUSR1 signal to the firedown process.

For testing, use the --no-act or -n option and the shutdown will not be issued.

Remarks

• To prevent loss of data, only empty files and directories will trigger a shutdown.

• Several machines sharing the same synchronized directory can be controlled individually, since each requires a different trigger file.

• No code in the shared directory is executed.

• No file needs to be edited.

Installation

You can either

• clone or download the firedown repository and use [sudo] rake install to install firedown and its man page to /usr/local,

• put firedown manually into the search path of root,

• put firedown anywhere and invoke it using its full path.

Requirements

• Ruby must be installed on your system.

• No additional Ruby gems are needed to run firedown.

• firedown has been tested with Ruby 1.8.7 and Ruby 1.9.3 on a Linux machine.

Documentation

Use firedown --help to display a brief help message.

If you installed firedown using rake install you can read its man page with man firedown.

Reporting bugs

Report bugs on the firedown home page: https://github.com/stomar/firedown/

License

Copyright © 2012-2017 Marcus Stollsteimer

firedown is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License version 3 or later (GPLv3+), see www.gnu.org/licenses/gpl.html. There is NO WARRANTY, to the extent permitted by law.