ups.conf - UPS definitions for Network UPS Tools
This file is read by the driver controller upsdrvctl(8), the UPS drivers
that use the common core (see nutupsdrv(8), and upsd(8)). The
file begins with global directives, and then each UPS has a section which
contains a number of directives that set parameters for that UPS.
A UPS section begins with the name of the UPS in brackets, and
continues until the next UPS name in brackets or until EOF. The name
"default" is used internally in upsd, so you can’t use it
in this file.
You must define the driver and port elements for
each entry. Anything after that in a section is optional. A simple example
might look like this:
driver = blazer_ser
port = /dev/ttyS0
desc = "Web server UPS"
A slightly more complicated version includes some extras for the
hardware-specific part of the driver:
driver = apcsmart
port = /dev/cua00
cable = 940-0095B
sdtype = 2
desc = "Database server UPS"
In this case, the apcsmart(8) driver will receive variables
called "cable" and "sdtype" which have special meanings.
See the man pages of your driver(s) to learn which variables are supported
and what they do.
Optional. The driver will chroot(2) to this directory
during initialization. This can be useful when securing systems.
Optional. Path name of the directory in which the UPS
driver executables reside. If you don’t specify this, the programs look
in a built-in default directory, which is often /usr/local/ups/bin.
Optional. Same as the UPS field of the same name, but
this is the default for UPSes that don’t have the field.
Optional. Specify the number of attempts to start the
driver(s), in case of failure, before giving up. A delay of retrydelay
is inserted between each attempt. Caution should be taken when using this
option, since it can impact the time taken by your system to start.
The default is 1 attempt.
Optional. Specify the delay between each restart attempt
of the driver(s), as specified by maxretry
. Caution should be taken
when using this option, since it can impact the time taken by your system to
The default is 5 seconds.
Optional. The status of the UPS will be refreshed after a
maximum delay which is controlled by this setting. This is normally 2 seconds.
This may be useful if the driver is creating too much of a load on your system
Optional. The driver work by default in asynchronous mode
). This means that all data are pushed by the driver
on the communication socket to upsd (Unix socket on Unix, Named pipe on
Windows) without waiting for these data to be actually consumed. With some HW,
such as ePDUs, that can produce a lot of data, asynchronous mode may cause
some congestion, resulting in the socket to be full, and the driver to appear
as not connected. In such case, the driver will provide the following debug
write XX bytes to socket Y failed
By enabling the synchronous flag (value = yes), the
driver will wait for data to be consumed by upsd, prior to publishing more.
This can be enabled either globally or per driver.
The default is no (i.e. asynchronous mode) for backward
compatibility of the driver behavior.
Optional. If started as root, the driver will setuid(2)
to the user id associated with username.
Required. This specifies which program will be monitoring
this UPS. You need to specify the one that is compatible with your hardware.
See nutupsdrv(8) for more information on drivers in general and
pointers to the man pages of specific drivers.
Required. This is the serial port where the UPS is
connected. On a Linux system, the first serial port usually is
/dev/ttyS0. On FreeBSD and similar systems, it probably will be
Optional. When you have multiple UPSes on your system,
you usually need to turn them off in a certain order. upsdrvctl shuts down all
the 0s, then the 1s, 2s, and so on. To exclude a UPS from the shutdown
sequence, set this to -1.
The default value for this parameter is 0.
Optional. This allows you to set a brief description that
upsd will provide to clients that ask for a list of connected equipment.
Optional. When you specify this, the driver skips the
port locking routines every time it starts. This may allow other processes to
seize the port if you start more than one accidentally.
You should only use this if your system won’t work without
This may be needed on Mac OS X systems.
Optional. When you specify this, the driver ignores a low
battery condition flag that is reported by the UPS (some devices will switch
off almost immediately after setting this flag, or will report this as soons
as the mains fails). Instead it will use either of the following conditions to
determine when the battery is low:
battery.charge < battery.charge.low
battery.runtime < battery.runtime.low
The idea is to set the battery.charge.low and/or
battery.runtime.low levels in ups.conf to a value that gives enough
time to cleanly shutdown your system:
override.battery.charge.low = 30
override.battery.runtime.low = 180
In order for this to work, your UPS should be able to (reliably)
report charge and/or runtime remaining on battery. Use with caution!
Optional. This can be set as a global variable above your
first UPS definition and it can also be set in a UPS section. This value
controls how long upsdrvctl will wait for the driver to finish starting. This
keeps your system from getting stuck due to a broken driver or UPS.
The default is 45 seconds.
Optional. Same as the global directive of the same name,
but this is for a specific device.
Optional. Force the USB code to call
usb_set_altinterface(0), as was done in NUT 2.7.2 and earlier. This should not
be necessary, since the default for bAlternateSetting (as shown in lsusb) is
zero on all USB devices seen to date. However, this redundant call to
usb_set_altinterface() prevents certain UPSes from working on Mac OS X. If
your UPS requires explicitly setting the alternate interface, include this
flag, and email the nut-upsdev list with details about your UPS and operating
Optional. Set a default value for <variable> which
is used in case the UPS doesn’t provide a value, but will be
overwritten if a value is available from the UPS:
default.input.voltage.nominal = 230
The above will report the nominal input voltage to be 230, unless
the UPS tells us differently.
Optional. Set a value for <value> that overrides
any value that may be read from the UPS. Used for overriding values from the
UPS that are clearly wrong (some devices report wrong values for battery
voltage for instance):
override.battery.voltage.nominal = 12
Use with caution! This will only change the appearance of the
variable to the outside world, internally in the UPS the original value is
All other fields are passed through to the hardware-specific part
of the driver. See those manuals for the list of what is allowed.
upsdrvctl(8) uses this file to start and stop the drivers.
The drivers themselves also obtain configuration data from this
file. Each driver looks up its section and uses that to configure
upsd(8) learns about which UPSes are installed on this
system by reading this file. If this system is called "doghouse"
and you have defined a UPS in your ups.conf called
"snoopy", then you can monitor it from upsc(8) or similar
upsd(8), nutupsdrv(8), upsdrvctl(8)