UPSMON.CONF(5) Network UPS Tools (NUT) UPSMON.CONF(5)
upsmon.conf - Configuration for Network UPS Tools upsmon
This file's primary job is to define the systems that upsmon(8) will monitor and to tell
it how to shut down the system when necessary. It will contain passwords, so keep it
secure. Ideally,only the upsmon process should be able to read it.
Additionally, other optional configuration values can be set in this file.
upsmon allows a UPS to go missing for this many seconds before declaring it "dead".
The default is 15 seconds.
upsmon requires a UPS to provide status information every few seconds (see POLLFREQ
and POLLFREQALERT) to keep things updated. If the status fetch fails, the UPS is
marked stale. If it stays stale for more than DEADTIME seconds, the UPS is marked
A dead UPS that was last known to be on battery is assumed to have changed to a low
battery condition. This may force a shutdown if it is providing a critical amount
of power to your system. This seems disruptive, but the alternative is barreling
ahead into oblivion and crashing when you run out of power.
Note: DEADTIME should be a multiple of POLLFREQ and POLLFREQALERT. Otherwise,
you'll have "dead" UPSes simply because upsmon isn't polling them quickly enough.
Rule of thumb: take the larger of the two POLLFREQ values, and multiply by 3.
When running in master mode, upsmon waits this long after sending the NOTIFY_SHUT-
DOWN to warn the users. After the timer elapses, it then runs your SHUTDOWNCMD.
By default this is set to 5 seconds.
If you need to let your users do something in between those events, increase this
number. Remember, at this point your UPS battery is almost depleted, so don't make
this too big.
Alternatively, you can set this very low so you don't wait around when it's time to
shut down. Some UPSes don't give much warning for low battery and will require a
value of 0 here for a safe shutdown.
Note: If FINALDELAY on the slave is greater than HOSTSYNC on the master, the master
will give up waiting for the slave to disconnect.
upsmon will wait up to this many seconds in master mode for the slaves to discon-
nect during a shutdown situation. By default, this is 15 seconds.
When a UPS goes critical (on battery + low battery, or "FSD" - forced shutdown),
the slaves are supposed to disconnect and shut down right away. The HOSTSYNC timer
keeps the master upsmon from sitting there forever if one of the slaves gets stuck.
This value is also used to keep slave systems from getting stuck if the master
fails to respond in time. After a UPS becomes critical, the slave will wait up to
HOSTSYNC seconds for the master to set the FSD flag. If that timer expires, the
slave will assume that the master is broken and will shut down anyway.
This keeps the slaves from shutting down during a short-lived status change to "OB
LB" that the slaves see but the master misses.
Set the number of power supplies that must be receiving power to keep this system
running. Normal computers have just one power supply, so the default value of 1 is
Large/expensive server type systems usually have more, and can run with a few miss-
ing. The HP NetServer LH4 can run with 2 out of 4, for example, so you'd set it to
2. The idea is to keep the box running as long as possible, right?
Obviously you have to put the redundant supplies on different UPS circuits for this
to make sense! See big-servers.txt in the docs subdirectory for more information
and ideas on how to use this feature.
Also see the section on "power values" in upsmon(8).
MONITOR system powervalue username password type
Each UPS that you need to be monitor should have a MONITOR line. Not all of these
need supply power to the system that is running upsmon. You may monitor other sys-
tems if you want to be able to send notifications about status changes on them.
You must have at least one MONITOR directive in this file.
system is a UPS identifier. It is in this form:
"localhost" is the first UPS on the local system.
"su700@mybox" is a UPS called "su700" ([su700] in ups.conf) on a system called
"elvis:1234" is the first UPS on a system called elvis, which is running
upsd(8) on port 1234.
To use all of the options together:
"fenton@bigbox:5678" is a UPS called "fenton" on a system called "bigbox"
which runs upsd(8) on port 5678. Phew!
powervalue is an integer representing the number of power supplies that the UPS
feeds on this system. Most normal computers have one power supply, and the UPS
feeds it, so this value will be 1. You need a very large or special system to have
anything higher here.
You can set the powervalue to 0 if you want to monitor a UPS that doesn't actually
supply power to this system. This is useful when you want to have upsmon do noti-
fications about status changes on a UPS without shutting down when it goes criti-
The username and password on this line must match an entry in that system's
upsd.users(5). If your username is "monmaster" and your password is "blah", the
MONITOR line might look like this:
MONITOR myups@bigserver 1 monmaster blah master
Meanwhile, the upsd.users on 'bigserver' would look like this:
password = blah
allowfrom = (ACLs from upsd.conf(5))
upsmon master (or slave)
The type refers to the relationship with upsd(8). It can be either "master" or
"slave". See upsmon(8) for more information on the meaning of these modes. The
mode you pick here also goes in the upsd.users file, as seen in the example above.
upsmon will trigger a NOTIFY_NOCOMM after this many seconds if it can't reach any
of the UPS entries in this configuration file. It keeps warning you until the sit-
uation is fixed. By default this is 300 seconds.
upsmon calls this to send messages when things happen.
This command is called with the full text of the message as one argument. The
environment string NOTIFYTYPE will contain the type string of whatever caused this
event to happen.
If you need to use upssched(8), then you must make it your NOTIFYCMD by listing it
Note that this is only called for NOTIFY events that have EXEC set with NOTIFYFLAG.
See NOTIFYFLAG below for more details.
Making this some sort of shell script might not be a bad idea. For more informa-
tion and ideas, see pager.txt in the docs directory.
Remember, this also needs to be one element in the configuration file, so if your
command has spaces, then wrap it in quotes.
NOTIFYCMD "/path/to/script --foo --bar"
This script is run in the background - that is, upsmon forks before it calls out to
start it. This means that your NOTIFYCMD may have multiple instances running
simultaneously if a lot of stuff happens all at once. Keep this in mind when
designing complicated notifiers.
NOTIFYMSG type message
upsmon comes with a set of stock messages for various events. You can change them
if you like.
NOTIFYMSG ONLINE "UPS %s is getting line power"
NOTIFYMSG ONBATT "Someone pulled the plug on %s"
Note that %s is replaced with the identifier of the UPS in question.
Possible values for type:
ONLINE - UPS is back online
ONBATT - UPS is on battery
LOWBATT - UPS is on battery and has a low battery (is critical)
FSD - UPS is being shutdown by the master (FSD = "Forced Shutdown")
COMMOK - Communications established with the UPS
COMMBAD - Communications lost to the UPS
SHUTDOWN - The system is being shutdown
REPLBATT - The UPS battery is bad and needs to be replaced
NOCOMM - A UPS is unavailable (can't be contacted for monitoring)
The message must be one element in the configuration file, so if it contains spa-
ces, you must wrap it in quotes.
NOTIFYMSG NOCOMM "Someone stole UPS %s"
NOTIFYFLAG type flag[+flag][+flag]...
By default, upsmon sends walls global messages to all logged in users) via
/bin/wall and writes to the syslog when things happen. You can change this.
NOTIFYFLAG ONLINE SYSLOG
NOTIFYFLAG ONBATT SYSLOG+WALL+EXEC
Possible values for the flags:
SYSLOG - Write the message to the syslog
WALL - Write the message to all users with /bin/wall
EXEC - Execute NOTIFYCMD (see above) with the message
IGNORE - Don't do anything
If you use IGNORE, don't use any other flags on the same line.
Normally upsmon polls the upsd(8) server every 5 seconds. If this is flooding your
network with activity, you can make it higher. You can also make it lower to get
faster updates in some cases.
There are some catches. First, if you set the POLLFREQ too high, you may miss
short-lived power events entirely. You also risk triggering the DEADTIME (see
above) if you use a very large number.
Second, there is a point of diminishing returns if you set it too low. While upsd
normally has all of the data available to it instantly, most drivers only refresh
the UPS status once every 2 seconds. Polling any more than that usually doesn't
get you the information any faster.
This is the interval that upsmon waits between polls if any of its UPSes are on
battery. You can use this along with POLLFREQ above to slow down polls during nor-
mal behavior, but get quicker updates when something bad happens.
This should always be equal to or lower than the POLLFREQ value. By default it is
also set 5 seconds.
The warnings from the POLLFREQ entry about too-high and too-low values also apply
upsmon creates this file when running in master mode when the UPS needs to be pow-
ered off. You should check for this file in your shutdown scripts and call ups-
drvctl shutdown if it exists.
This is done to forcibly reset the slaves, so they don't get stuck at the "halted"
stage even if the power returns during the shutdown process. This usually does not
work well on contact-closure UPSes that use the genericups driver.
See the shutdown.txt file in the docs subdirectory for more information.
When a UPS says that it needs to have its battery replaced, upsmon will generate a
NOTIFY_REPLBATT event. By default this happens every 43200 seconds - 12 hours.
If you need another value, set it here.
upsmon normally runs the bulk of the monitoring duties under another user ID after
dropping root privileges. On most systems this means it runs as "nobody", since
that's the default from compile-time.
The catch is that "nobody" can't read your upsmon.conf, since by default it is
installed so that only root can open it. This means you won't be able to reload
the configuration file, since it will be unavailable.
The solution is to create a new user just for upsmon, then make it run as that
user. I suggest "nutmon", but you can use anything that isn't already taken on
your system. Just create a regular user with no special privileges and an impossi-
Then, tell upsmon to run as that user, and make upsmon.conf readable by it. Your
reloads will work, and your config file will stay secure.
This file should not be writable by the upsmon user, as it would be possible to
exploit a hole, change the SHUTDOWNCMD to something malicious, then wait for upsmon
to be restarted.
upsmon runs this command when the system needs to be brought down. If it is a
slave, it will do that immediately whenever the current overall power value drops
below the MINSUPPLIES value above.
When upsmon is a master, it will allow any slaves to log out before starting the
local shutdown procedure.
Note that the command needs to be one element in the config file. If your shutdown
command includes spaces, then put it in quotes to keep it together, i.e.:
SHUTDOWNCMD "/sbin/shutdown -h +0"
upsmon(8), upsd(8), nutupsdrv(8).
The NUT (Network UPS Tools) home page: http://www.exploits.org/nut/
NUT mailing list archives and information: http://lists.exploits.org/
Wed Oct 16 2002 UPSMON.CONF(5)