upsmon -c command
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.
Display the help message.
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
reload - reread upsmon.conf(5) configuration file
Enable debugging mode. upsmon runs in the foreground and prints debugging information on stdout about the monitoring process.
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.
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
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.
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 [[ __
Other possibilities include:
Finally, to use all of these options:
upsd__(8)? on port __
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.
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
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.
In upsmon.conf(5), you can configure a program called the NOTIFYCMD that will handle events that occur.
NOTIFYCMD path to program
Remember to wrap the path in
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.
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
NOTIFYFLAG ONLINE SYSLOG
NOTIFYFLAG ONBATT SYSLOG+WALL
NOTIFYFLAG LOWBATT SYSLOG+WALL+EXEC
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'.
Execute the NOTIFYCMD.
Don't do anything. If you use this, don't use any of the other flags.
upsmon comes with default messages for each of the NOTIFY events. These can be changed with the NOTIFYMSG directive.
NOTIFYMSG type message''
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. Don't set this to
MONITOR faraway@anotherbox 0 mypassword slave
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.
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.
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 __
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.
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.
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.
When upsmon is forced to bring down the local system, it sets the
In the event that upsmon can't reach upsd(8), it declares that UPS 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 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
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
The NUT (Network UPS Tools) home page: http://www.exploits.org/nut/