UPSSCHED(8) Network UPS Tools (NUT) UPSSCHED(8)NAMEupssched - Timer helper for scheduling events from upsmon
SYNOPSISupsschedNOTEupssched should be run from upsmon(8) via the NOTIFYCMD.
You should never run it directly during normal operations.
DESCRIPTIONupssched was created to allow users to execute programs at
times relative to events being monitored by upsmon(8).
The original purpose was to allow for a shutdown to occur
after some fixed period on battery, but there are other
uses that are possible.
INTEGRATIONupssched needs to be called as the NOTIFYCMD in your
upsmon.conf(5). It determines what is happening based on
the UPSNAME and NOTIFYTYPE environment variables. You
should never have to deal with them directly.
Set the EXEC flag on the events that you want to see in
upssched. For example, to make sure that upssched hears
about ONLINE, ONBATT and LOWBATT events, the flags would
look like this:
NOTIFYFLAG ONLINE EXEC
NOTIFYFLAG ONBATT EXEC
NOTIFYFLAG LOWBATT EXEC
If you also want to continue writing to the syslog, just
add it in:
NOTIFYFLAG ONLINE SYSLOG+EXEC
NOTIFYFLAG ONBATT SYSLOG+EXEC
NOTIFYFLAG LOWBATT SYSLOG+EXEC
For a full list of notify flags, see the upsmon(8) docu-
mentation.
CONFIGURATION
See upssched.conf(5) for information on configuring this
program.
EARLY SHUTDOWNS
To shut down the system early, define a timer that starts
due to an ONBATT condition. When it triggers, make your
CMDSCRIPT call your shutdown routine. It should finish by
calling "upsmon -c fsd" so that upsmon gets to shut down
the slaves in a controlled manner.
Be sure you cancel the timer if power returns (ONLINE).
DEBOUNCING EVENTS
If your UPS goes on and off battery frequently, you can
use this program to reduce the number of pager messages
that are sent out. Rather than sending pages directly
from upsmon(8), use a short timer here. If the timer
triggers with the UPS still on battery, then send the
page. If the power returns before then, the timer can be
cancelled and no page is necessary.
BACKGROUND
This program was written primarily to fulfill the requests
of users for the early shutdown scenario. The "outboard"
design of the program (relative to upsmon) was intended to
reduce the load on the average system. Most people don't
have the requirement of shutting down after n seconds on
battery, since the usual OB+LB testing is sufficient.
This program was created separately so those people don't
have to spend CPU time and RAM on something that will
never be used in their environments.
The design of the timer handler is also geared towards
minimizing impact. It will come and go from the process
list as necessary. When a new timer is started, a process
will be forked to actually watch the clock and eventually
start the CMDSCRIPT. When a timer triggers, it is removed
from the queue. Cancelling a timer will also remove it
from the queue. When no timers are present in the queue,
the background process exits.
This means that you will only see upssched running when
one of two things is happening:
- There's a timer of some sort currently running
- upsmon just called it, and you managed to catch the
brief instance
The final optimization handles the possibility of trying
to cancel a timer when there are none running. If the
timer daemon isn't running, there are no timers to cancel,
and furthermore there is no need to start a clock-watcher.
So, it skips that step and exits sooner.
FILESupssched.conf(5)SEE ALSOupsmon(8)
Internet resources:
The NUT (Network UPS Tools) home page:
http://www.exploits.org/nut/
NUT mailing list archives and information:
http://lists.exploits.org/
Wed Feb 6 2002 UPSSCHED(8)
