watchdogtimerd(8) System Manager's Manual watchdogtimerd(8)
NAME
watchdogtimerd -- Mac OS X Server automatic reboot daemon (hardware
watchdog tickler)
SYNOPSIS
watchdogtimerd [-d | -n | -R] [-i interval] [-c count] [-L facility]
watchdogtimerd [-h | -v]
DESCRIPTION
watchdogtimerd is indirectly responsible for rebooting the server hard-
ware if the machine hangs or panics. When watchdogtimerd runs on sup-
ported hardware, it periodically resets the hardware watchdog timer. If
the timer ever expires, the power management unit forces a hard reboot.
Automatic reboot is disabled when watchdogtimerd quits cleanly, so it is
imperative watchdogtimerd be terminated by sending a termination signal
(SIGTERM), NOT a kill signal (SIGKILL)!
watchdogtimerd is typically launched at boot time under the control of
launchd(8) using the job label com.apple.watchdogtimerd.
OPTIONS
The following options are available:
-c count
--cycles=count Reboot the machine if the timer has not been reset
for count intervals. This option is primarily used
when debugging. Valid range of values is 3 through
480. Default is 10 with most configurations, result-
ing in a reboot within five minutes after failure.
If the kernel's boot-args contained the "_panicd_ip"
directive to enable panic dumps (as noted in the
referenced Tech Note below), the default is raised
to 30, resulting in a reboot after fifteen minutes
to allow enough time for the kernel to send the dump
information.
-d
--debug Print log strings to the terminal.
-h
--help Print usage summary and exit.
-i interval
--interval=interval Reset the watchdog timer every interval seconds.
This option is primarily used when debugging. Valid
range of values is 1 through 30. Default is 30.
-L facility Enable logging to syslog(8) using the specified
facility. The following values for facility are
supported: daemon (the default), user, local[0-7].
(See syslog.conf(5) for their meanings.) This is
equivalent to --syslog.
-n
--no-run Print log information to the terminal and quit after
validating the hardware watchdog timer.
-R
--reboot Force a hard reboot by initializing the watchdog
timer to (count * interval) seconds and terminating.
--syslog=facility Enable logging to syslog(8) using the specified
facility. The following values for facility are
supported: daemon (the default), auth, user,
local[0-7]. (See syslog.conf(5) for their mean-
ings.) This is equivalent to -L.
-v
--version Print build version and exit.
FILES & FOLDERS
/usr/sbin/watchdogtimerd
- daemon
/System/Library/LaunchDaemons/com.apple.watchdogtimerd.plist
- launchd(8) configuration file.
DIAGNOSTICS
The watchdogtimerd utility exits 0 on success, and >0 if an error occurs.
The following table lists possible exit codes, their equivalent constants
in sysexits(3), and their corresponding failure condition.
code constant failure condition
64 EX_USAGE invalid arguments
69 EX_UNAVAILABLE automatic reboot timer unavailable
77 EX_NOPERM insufficient permissions
Could not access automatic reboot timer. The executing machine does not
support a hardware watchdog timer.
Invalid interval. Valid intervals range from 1 to 30.
Invalid number of cycles. Valid cycles range from 3 to 480.
Unable to raise process priority. watchdogtimerd was unable to raise its
priority. This may result in inadvertant reboots if other (typically
real-time) processes consume all available cycles.
watchdogtimerd must be executed as root. Because watchdogtimerd controls
system-wide resources, it must be executed by the root user.
SEE ALSO
sysexits(3), syslog.conf(5), launchctl(8), launchd(8), syslogd(8)
Apple's technical note TN2118: Kernel Core Dumps <http://
developer.apple.com/technotes/tn2004/tn2118.html> describes how to set up
a crash dump server and how to send dumps from panicked machines. These
instructions allow a site to record kernel panics for debugging or analy-
sis while leveraging the higher service availability provided by
watchdogtimerd. This approach is recommended for most sites instead of
increasing the time before forcing a reboot. (As noted in the OPTIONS
section, the minimum reboot time is extended if such dumping is config-
ured.)
KNOWN ISSUES
None identified at this time.
HISTORY
watchdogtimerd replaces the hardware watchdog timer servicing of
watchdog(8).
The pressing question used to be, "Who watches the watchmen?" Now we
know: launchd(8).
Mac OS X Server 10.6 May 12, 2008 Mac OS X Server 10.6
Mac OS X 10.6Server - Generated Thu Apr 15 07:13:23 CDT 2010