UPSMON(8)

NAME
upsmon - UPS monitor and shutdown controller

SYNOPSIS
upsmon -h upsmon -c command upsmon [-d] [-i] [-p] [-u user]

DESCRIPTION
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).

OPTIONS

-h  Display the help message.

-c command
    Send the command command to the existing upsmon process. Valid commands are: fsd - shutdown all master UPSes (use with caution) stop - stop monitoring and exit

-d  Enable debugging mode. upsmon runs in the foreground and prints debugging information on stdout about the monitoring process.

-i  Enable infinite loop at shutdown. upsmon will keep a process running after calling the shutdown command rather than exiting. This is only useful if you have shutdown scripts that complain when upsmon isn't running as they kill various processes.

-p  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.

-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.

UPS DEFINITIONS
In the upsmon.conf(5), you must specify at least one UPS that will be monitored. Use the MONITOR directive.
    MONITOR system powervalue password type The system refers to a upsd(8) server, in the form [<upsname>@]hostname[:port]. The simplest form is just a hostname, i.e.:
    "localhost" refers to the first UPS on the local system. Other possibilities include:
    "su700@mybox" means a UPS called "su700" on a system called "mybox".
    "elvis:1234" means the first UPS on a system called "elvis", port 1234. Finally, to use all of these options:
    "fenton@bigbox:5678" is a UPS called "fenton" on a system called "bigbox" which runs upsd(8) on port "5678". Phew! 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. Your password must match the entry in the upsd(8) server's upsd.conf(5) ACCESS directive for this system. The type is either 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.

NOTIFY EVENTS
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.

ONLINE
    The UPS is back on line.

ONBATT
    The UPS is on battery.

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

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

COMMOK
    Communication with the UPS has been established.

COMMBAD
    Communication with the UPS was just lost.

SHUTDOWN
    The local system is being shut down.

REPLBATT
    The UPS needs to have its battery replaced.

NOCOMM
    The UPS can't be contacted for monitoring.

NOTIFY COMMAND
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:

NOTIFY FLAGS
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
    Examples:
    NOTIFYFLAG ONLINE SYSLOG
    NOTIFYFLAG ONBATT SYSLOG+WALL
    NOTIFYFLAG LOWBATT SYSLOG+WALL+EXEC The flags that can be set on a given notify event are:

SYSLOG
    Write this message to the syslog.

WALL
    Send this message to all users on the system via 'wall'.

EXEC
    Execute the NOTIFYCMD.

IGNORE
    Don't do anything. If you use this, don't use any of the other flags.

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

NOTIFY MESSAGES
upsmon comes with default messages for each of the NOTIFY events. These can be changed with the NOTIFYMSG directive.
    NOTIFYMSG type "message"
    Examples:
    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.

POWER VALUES
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 password type Normally, you only have one power supply, so it will be set to 1.
    MONITOR myups@myhost 1 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 defined.
    MONITOR ups-alpha@myhost 2 mypassword master
    MONITOR ups-beta@myhost 2 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. The master/slave distinction does not apply here, since no power is coming from this UPS.
    MONITOR faraway@anotherbox 0 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.
    MINSUPPLIES 1 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.
    MINSUPPLIES 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.

UPS TYPES
Remember that upsmon and upsd(8) need not run on the same system. When they do, upsmon needs to monitor those UPSes as a master. This means that it will take charge of that UPS, and wait for all of the slaves to disconnect before shutting itself down. This synchronization ensures that systems that do monitoring over the network can shut down cleanly before the master's driver shutdown (-k) command turns them 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. At the same time, don't set this too high, or your UPS battery may run out of power before the master upsmon process shuts down that system.

TIMED SHUTDOWNS
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's run on battery too long. This can be complicated and messy, so stick to the default critical UPS handling if you can.

REDUNDANT POWER SUPPLIES
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 both 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.

MIXED OPERATIONS
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.

FORCED SHUTDOWNS
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 upssched(8).

DEAD UPSES
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.

FILES
upsmon.conf(5)

SEE ALSO

  Server:
upsd(8)

  Clients:
upsc(8), upscmd(8), upsct(8), upsct2(8), upsmon(8)

  CGI programs:
upsset.cgi, multimon.cgi, upsstats.cgi, upsimage.cgi

  Internet resources:
The NUT (Network UPS Tools) home page: http://www.exploits.org/nut/ The user mailing list: ups@lists.exploits.org