NAME
dummy-ups - Driver for multi-purpose UPS emulation
NOTE
This man page only documents the specific features of the dummy-ups driver. For information about the core driver, see nutupsdrv(8).
DESCRIPTION
This program is a multi-purpose UPS emulation tool. Its behavior depends on the running mode: "dummy" or "repeater".
Dummy Mode
In this mode, dummy-ups looks like a standard NUT device driver to upsd(8) and allows one to change any value for testing purposes. It is both interactive, controllable through the upsrw(1) and upscmd(1) commands (or equivalent graphical tool), and batchable through script files. It can be configured, launched and used as any other "real" NUT driver. This mode is mostly useful for development and testing purposes.
Repeater Mode
In this mode, dummy-ups acts as a NUT client, simply forwarding data.
This can be useful for supervision purposes. This mode can also allow some
load sharing between several upsd instances communicating with ultimate
NUT clients, with a "central" one using a point-to-point communication with
the UPS. This arrangement can also help with networked UPSes, whose network
management cards can be overwhelmed with a farm of servers directly polling
SNMP or other protocols every few seconds.
IMPLEMENTATION
The port specification in ups.conf depends on the running mode, and allows
the driver to select the right mode of operation.
Dummy Mode
In this context, port in the ups.conf block defines a file name for the
dummy-ups to read data from. This can either be an absolute or a relative
path name. In the latter case the NUT sysconfig directory (i.e. /etc/nut,
/usr/local/ups/etc, …) is prepended.
For instance:
[dummy]
driver = dummy-ups
port = evolution500.seq
desc = "dummy-ups in dummy mode"This file is generally named something.dev or something.seq. It contains
a list of all valid variables and associated values (you can later use upsrw
only to modify values of these variables), and has the same format as an
upsc(8) dump (<varname>: <value>). So you can easily create
definition files from an existing UPS using upsc > file.dev.
Note that the Network UPS project provides a DDL (Devices Dumps Library) at
link:https://networkupstools.org/ddl/index.html with files which can be used
for modelling real devices. Entries for the DDL library are prepared with the
./tools/nut-ddl-dump.sh script from NUT sources instead of plain upsc to
provide some other data points from other NUT clients as well.
The file can also be empty, in which case only a basic set of data is
available: device.*, driver.*, ups.mfr, ups.model, ups.status
as filled by the driver itself.
Some sample definition files are available in the data directory of the
NUT source tree, and generally in the sysconfig directory of your system
distribution.
Since dummy-ups will loop on reading this file, you can dynamically modify it with some external process to "interact" with the driver. This will avoid message spam into your system log files, if you are using NUT default configuration.
You can also use the TIMER <seconds> instruction to create scheduled event
sequences (such files are traditionally named with the .seq extension).
For example, the following sequence will loop on switching ups.status
between "OL", "OB" and "OB LB" every minute:
ups.status: OL
TIMER 60
ups.status: OB
TIMER 60
ups.status: OB LB
TIMER 60It is wise to end the script with a TIMER keyword. Otherwise dummy-ups
will directly go back to the beginning of the file and, in particular, forget
any values you could have just set with upsrw.
Note that to avoid CPU overload with an infinite loop, the driver "sleeps"
a bit between file-reading cycles (currently this delay is hardcoded to one
second), independently of (and/or in addition to) any TIMER keywords.
Repeater Mode
In this context, port in the ups.conf block is the name of a remote UPS,
using the NUT format, i.e.:
<upsname>@<hostname>[:<port>]For instance:
[repeater]
driver = dummy-ups
port = ups1@remotehost
desc = "dummy-ups in repeater mode"Unlike UPS specifications in the rest of NUT, the @hostname portion is not
optional - it is the @ character which enables Repeater Mode. To refer to an
UPS on the same host as dummy-ups, use port = upsname@localhost.
Note that to avoid CPU overload with an infinite loop, the driver "sleeps" a
bit between data-requesting cycles (currently this delay is hardcoded to one
second), so propagation of data updates available to a remote upsd may lag
by this much.
INTERACTION
Once the driver is loaded in dummy mode, you can change any variables, except
those of the driver.* and server.* collections.
You can do this by either editing the definition file, or use the
upsrw(1) and upscmd(1) commands.
Note that in simulation mode, new variables can be added on the fly, but only
by adding these to the definition file (and waiting for it to be re-read).
Conversely, if you need to remove variable (such as transient ones, like
ups.alarm), simply update these by setting an empty value. As a result,
they will get removed from the data.
In repeater mode, the driver acts according to the capabilities of the UPS, and so supports the same instant commands and settable values.
BACKGROUND
Dummy Mode was originally written in one evening to replace the previous dummycons testing driver, which was too limited, and required a terminal for interaction.
dummy-ups is useful for NUT client development, and other testing purposes.
It also helps the NUT Quality Assurance effort, by automating some tests on the NUT framework.
It now offers a repeater mode. This will help in building the Meta UPS approach, which allows one to build a virtual device, composed of several other devices (either UPS, PDUs).
BUGS
Instant commands are not yet supported in Dummy Mode, and data need name/value checking enforcement, as well as boundaries or enumeration definition.
AUTHOR
Arnaud Quette
SEE ALSO
Internet Resources:
The NUT (Network UPS Tools) home page: http://www.networkupstools.org/