Network UPS Tools is a collection of programs which provide a common interface for monitoring and administering UPS, PDU and SCD hardware. It uses a layered approach to connect all of the parts.
Drivers are provided for a wide assortment of equipment. They understand the specific language of each device and map it back to a compatibility layer. This means both an expensive high end UPS, a simple "power strip" PDU, or any other power device can be handled transparently with a uniform management interface.
This information is cached by the network server upsd, which then
answers queries from the clients. upsd contains a number of access
control features to limit the abilities of the clients. Only authorized
hosts may monitor or control your hardware if you wish. Since the
notion of monitoring over the network is built into the software, you
can hang many systems off one large UPS, and they will all shut down
together. You can also use NUT to power on, off or cycle your data center
nodes, individually or globally through PDU outlets.
Clients such as upsmon check on the status of the hardware and do things
when necessary. The most important task is shutting down the operating
system cleanly before the UPS runs out of power. Other programs are
also provided to log information regularly, monitor status through your
web browser, and more.
NUT comes pre-packaged for many operating systems and embedded in storage, automation or virtualization appliances, and is also often shipped as the software companion by several UPS vendors. Of course, it is quite normal and supported to build your own — whether for an operating system which lacks it yet, or for an older distribution which lacks the current NUT version; whether to take advantage of new features or to troubleshoot a new UPS deployment with a debugger in hand.
Given its core position at the heart of your systems' lifecycle, we make it a point to have current NUT building and running anywhere, especially where older releases did work before (including "abandonware" like the servers and OSes from the turn of millennium): if those boxes are still alive and in need of power protection, they should be able to get it.
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Tip
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If you like how the NUT project helps protect your systems from power outages, please consider sponsoring or at least "starring" it on GitHub at https://github.com/networkupstools/nut/ - these stars are among metrics which the larger potential sponsors consider when choosing how to help FOSS projects. Keeping the lights shining in such a large non-regression build matrix is a big undertaking! See acknowledgements of organizations which help with NUT CI and other daily operations for an overview of the shared effort. |
As a FOSS project, for over a quarter of a century we welcome contributions of both core code (drivers and other features), build recipes and other integration elements to make it work on your favourite system, documentation revisions to make it more accessible to newcomers, as well as hardware vendor cooperation with first-hand driver and protocol submissions, and just about anything else you can think of.
If you are installing these programs for the first time, go read the installation instructions to find out how to do that. This document contains more information on what all of this stuff does.
When upgrading from an older version, always check the upgrading notes to see what may have changed. Compatibility issues and other changes will be listed there to ease the process.
Once NUT is installed, refer to the configuration notes for directions.
This is just an overview of the software. You should read the man pages, included example configuration files, and auxiliary documentation for the parts that you intend to use.
These programs are designed to share information over the network. In
the examples below, localhost is used as the hostname. This can also
be an IP address or a fully qualified domain name. You can specify a
port number if your upsd process runs on another port.
In the case of the program upsc, to view the variables on the UPS called
sparky on the upsd server running on the local machine, you’d do this:
/usr/local/ups/bin/upsc sparky@localhost
The default port number is 3493. You can change this with "configure --with-port" at compile-time. To make a client talk to upsd on a specific port, add it after the hostname with a colon, like this:
/usr/local/ups/bin/upsc sparky@localhost:1234
This is handy when you have a mixed environment and some of the systems are on different ports.
The general form for UPS identifiers is this:
<upsname>[@<hostname>[:<port>]]
Keep this in mind when viewing the examples below.