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       upsmon - UPS monitor and shutdown controller


       upsmon -h

       upsmon -c command

       upsmon [-D] [-p] [-u user]


       upsmon is the client process that is responsible for the most important
       part of UPS monitoring—shutting down the system when the power goes
       out. It can call out to other helper programs for notification purposes
       during power events.

       upsmon can monitor multiple systems using a single process. Every UPS
       that is defined in the upsmon.conf(5) configuration file is assigned a
       power value and a type (slave or master).


           Display the help message.

       -c command
           Send the command command to the existing upsmon process. Valid
           commands are:

               shutdown all master UPSes (use with caution)

               stop monitoring and exit

               reread upsmon.conf(5) configuration file. See "reloading
               nuances" below if this doesn’t work.

           Raise the debugging level. upsmon will run in the foreground and
           prints information on stdout about the monitoring process. Use this
           multiple times for more details.

           Test for the shutdown flag. If it exists and contains the magic
           string from upsmon, then upsmon will exit with EXIT_SUCCESS. Any
           other condition will make upsmon exit with EXIT_FAILURE.

           You can test for a successful exit from upsmon -K in your shutdown
           scripts to know when to call upsdrvctl(8) to shut down the UPS.

           Run privileged all the time. Normally upsmon will split into two
           processes. The majority of the code runs as an unprivileged user,
           and only a tiny stub runs as root. This switch will disable that
           mode, and run the old "all root all the time" system.

           This is not the recommended mode, and you should not use this
           unless you have a very good reason.

       -u user
           Set the user for the unprivileged monitoring process. This has no
           effect when using -p.

           The default user is set at configure time with configure
           --with-user=.... Typically this is nobody, but other distributions
           will probably have a specific nut user for this task. If your
           notification scripts need to run as a specific user, set it here.

           You can also set this in the upsmon.conf(5) file with the
           RUN_AS_USER directive.


       In the upsmon.conf(5), you must specify at least one UPS that will be
       monitored. Use the MONITOR directive.

           MONITOR 'system' 'powervalue' 'username' 'password' 'type'

       The system refers to a upsd(8) server, in the form
       upsname[@hostname[:port]]. The default hostname is "localhost". Some
       examples follow:

       ·   "su700@mybox" means a UPS called "su700" on a system called
           "mybox". This is the normal form.

       ·   "fenton@bigbox:5678" is a UPS called "fenton" on a system called
           "bigbox" which runs upsd(8) on port "5678".

       The powervalue refers to how many power supplies on this system are
       being driven this UPS. This is typically set to 1, but see the section
       on power values below.

       The username is a section in your upsd.users(5) file. Whatever password
       you set in that section must match the password set in this file.

       The type set in that section must also match the type here-- master or
       slave. In general, a master process is one running on the system with
       the UPS actually plugged into a serial port, and a slave is drawing
       power from the UPS but can’t talk to it directly. See the section on
       UPS types for more.


       upsmon senses several events as it monitors each UPS. They are called
       notify events as they can be used to tell the users and admins about
       the change in status. See the additional NOTIFY-related sections below
       for information on customizing the delivery of these messages.

           The UPS is back on line.

           The UPS is on battery.

           The UPS battery is low (as determined by the driver).

           The UPS has been commanded into the "forced shutdown" mode.

           Communication with the UPS has been established.

           Communication with the UPS was just lost.

           The local system is being shut down.

           The UPS needs to have its battery replaced.

           The UPS can’t be contacted for monitoring.


       In upsmon.conf(5), you can configure a program called the NOTIFYCMD
       that will handle events that occur.

       NOTIFYCMD "path to program"

       NOTIFYCMD "/usr/local/bin/notifyme"

       Remember to wrap the path in "quotes" if it contains any spaces.

       The program you run as your NOTIFYCMD can use the environment variables
       NOTIFYTYPE and UPSNAME to know what has happened and on which UPS. It
       also receives the notification message (see below) as the first (and
       only) argument, so you can deliver a preformatted message too.

       Note that the NOTIFYCMD will only be called for a given event when you
       set the EXEC flag by using the notify flags, below:


       By default, all notify events (see above) generate a global message
       (wall) to all users, plus they are logged via the syslog. You can
       change this with the NOTIFYFLAG directive in the configuration file:

       NOTIFYFLAG notifytype flags





       The flags that can be set on a given notify event are:

           Write this message to the syslog.

           Send this message to all users on the system via wall(1).

           Execute the NOTIFYCMD.

           Don’t do anything. If you use this, don’t use any of the other

       You can mix these flags. "SYSLOG+WALL+EXEC" does all three for a given


       upsmon comes with default messages for each of the NOTIFY events. These
       can be changed with the NOTIFYMSG directive.

       NOTIFYMSG type "message"


       ·    NOTIFYMSG ONLINE "UPS %s is getting line power"

       ·   ` NOTIFYMSG ONBATT "Someone pulled the plug on %s"`

       The first instance of %s is replaced with the identifier of the UPS
       that generated the event. These messages are used when sending walls to
       the users directly from upsmon, and are also passed to the NOTIFYCMD.


       The "current overall power value" is the sum of all UPSes that are
       currently able to supply power to the system hosting upsmon. Any UPS
       that is either on line or just on battery contributes to this number.
       If a UPS is critical (on battery and low battery) or has been put into
       "forced shutdown" mode, it no longer contributes.

       A "power value" on a MONITOR line in the config file is the number of
       power supplies that the UPS runs on the current system.

       MONITOR upsname powervalue username password type

       Normally, you only have one power supply, so it will be set to 1.

       MONITOR myups@myhost 1 username mypassword master

       On a large server with redundant power supplies, the power value for a
       UPS may be greater than 1. You may also have more than one of them

       MONITOR ups-alpha@myhost 2 username mypassword master

       MONITOR ups-beta@myhost 2 username mypassword master

       You can also set the power value for a UPS to 0 if it does not supply
       any power to that system. This is generally used when you want to use
       the upsmon notification features for a UPS even though it’s not
       actually running the system that hosts upsmon. Don’t set this to
       "master" unless you really want to power this UPS off when this
       instance of upsmon needs to shut down for its own reasons.

       MONITOR faraway@anotherbox 0 username mypassword slave

       The "minimum power value" is the number of power supplies that must be
       receiving power in order to keep the computer running.

       MINSUPPLIES value

       Typical PCs only have 1, so most users will leave this at the default.


       If you have a server or similar system with redundant power, then this
       value will usually be set higher. One that requires three power
       supplies to be running at all times would simply set it to 3.


       When the current overall power value drops below the minimum power
       value, upsmon starts the shutdown sequence. This design allows you to
       lose some of your power supplies in a redundant power environment
       without bringing down the entire system while still working properly
       for smaller systems.


       upsmon and upsd(8) don’t always run on the same system. When they do,
       any UPSes that are directly attached to the upsmon host should be
       monitored in "master" mode. This makes upsmon take charge of that
       equipment, and it will wait for slaves to disconnect before shutting
       down the local system. This allows the distant systems (monitoring over
       the network) to shut down cleanly before upsdrvctl shutdown runs and
       turns them all off.

       When upsmon runs as a slave, it is relying on the distant system to
       tell it about the state of the UPS. When that UPS goes critical (on
       battery and low battery), it immediately invokes the local shutdown
       command. This needs to happen quickly. Once it disconnects from the
       distant upsd(8) server, the master upsmon will start its own shutdown
       process. Your slaves must all shut down before the master turns off the
       power or filesystem damage may result.

       upsmon deals with slaves that get wedged, hang, or otherwise fail to
       disconnect from upsd(8) in a timely manner with the HOSTSYNC timer.
       During a shutdown situation, the master upsmon will give up after this
       interval and it will shut down anyway. This keeps the master from
       sitting there forever (which would endanger that host) if a slave
       should break somehow. This defaults to 15 seconds.

       If your master system is shutting down too quickly, set the FINALDELAY
       interval to something greater than the default 15 seconds. Don’t set
       this too high, or your UPS battery may run out of power before the
       master upsmon process shuts down that system.


       For those rare situations where the shutdown process can’t be completed
       between the time that low battery is signalled and the UPS actually
       powers off the load, use the upssched(8) helper program. You can use it
       along with upsmon to schedule a shutdown based on the "on battery"
       event. upssched can then come back to upsmon to initiate the shutdown
       once it has run on battery too long.

       This can be complicated and messy, so stick to the default critical UPS
       handling if you can.


       If you have more than one power supply for redundant power, you may
       also have more than one UPS feeding your computer. upsmon can handle
       this. Be sure to set the UPS power values appropriately and the
       MINSUPPLIES value high enough so that it keeps running until it really
       does need to shut down.

       For example, the HP NetServer LH4 by default has 3 power supplies
       installed, with one bay empty. It has two power cords, one per side of
       the box. This means that one power cord powers two power supply bays,
       and that you can only have two UPSes supplying power.

       Connect UPS "alpha" to the cord feeding two power supplies, and UPS
       "beta" to the cord that feeds the third and the empty slot. Define
       alpha as a powervalue of 2, and beta as a powervalue of 1. Set the
       MINSUPPLIES to 2.

       When alpha goes on battery, your current overall power value will stay
       at 3, as it’s still supplying power. However, once it goes critical (on
       battery and low battery), it will stop contributing to the current
       overall power value. That means the value will be 1 (beta alone), which
       is less than 2. That is insufficient to run the system, and upsmon will
       invoke the shutdown sequence.

       However, if beta goes critical, subtracting its contribution will take
       the current overall value from 3 to 2. This is just high enough to
       satisfy the minimum, so the system will continue running as before. If
       beta returns later, it will be re-added and the current value will go
       back to 3. This allows you to swap out UPSes, change a power
       configuration, or whatever, as long as you maintain the minimum power
       value at all times.


       Besides being able to monitor multiple UPSes, upsmon can also monitor
       them as different roles. If you have a system with multiple power
       supplies serviced by separate UPS batteries, it’s possible to be a
       master on one and a slave on the other. This usually happens when you
       run out of serial ports and need to do the monitoring through another
       system nearby.

       This is also complicated, especially when it comes time to power down a
       UPS that has gone critical but doesn’t supply the local system. You can
       do this with some scripting magic in your notify command script, but
       it’s beyond the scope of this manual.


       When upsmon is forced to bring down the local system, it sets the "FSD"
       (forced shutdown) flag on any UPSes that it is running in master mode.
       This is used to synchronize slaves in the event that a master UPS that
       is otherwise OK needs to be brought down due to some pressing event on
       the master.

       You can manually invoke this mode on the master upsmon by starting
       another copy with -c fsd. This is useful when you want to initiate a
       shutdown before the critical stage through some external means, such as


       In the event that upsmon can’t reach upsd(8), it declares that UPS
       "dead" after some interval controlled by DEADTIME in the
       upsmon.conf(5). If this happens while that UPS was last known to be on
       battery, it is assumed to have gone critical and no longer contributes
       to the overall power value.

       upsmon will alert you to a UPS that can’t be contacted for monitoring
       with a "NOCOMM" notifier by default every 300 seconds. This can be
       changed with the NOCOMMWARNTIME setting.


       upsmon usually gives up root powers for the process that does most of
       the work, including handling signals like SIGHUP to reload the
       configuration file. This means your upsmon.conf(8) file must be
       readable by the non-root account that upsmon switches to.

       If you want reloads to work, upsmon must run as some user that has
       permissions to read the configuration file. I recommend making a new
       user just for this purpose, as making the file readable by "nobody"
       (the default user) would be a bad idea.

       See the RUN_AS_USER section in upsmon.conf(8) for more on this topic.

       Additionally, you can’t change the SHUTDOWNCMD or POWERDOWNFLAG
       definitions with a reload due to the split-process model. If you change
       those values, you must stop upsmon and start it back up. upsmon will
       warn you in the syslog if you make changes to either of those values
       during a reload.


       To test a synchronized shutdown without pulling the plug on your
       UPS(es), you need only set the forced shutdown (FSD) flag on them. You
       can do this by calling upsmon again to set the flag, i.e.:

       upsmon -c fsd

       After that, the master and the slaves will do their usual shutdown
       sequence as if the battery had gone critical. This is much easier on
       your UPS equipment, and it beats crawling under a desk to find the





       upsc(8), upscmd(8), upsrw(8), upsmon(8)

   CGI programs:
       upsset.cgi(8), upsstats.cgi(8), upsimage.cgi(8)

   Internet resources:
       The NUT (Network UPS Tools) home page: