Recently I noticed that there are some warnings in the nagios.log
:
[1366060611] Warning: The check of service 'pt-deadlock-logger' on host 'xx' looks like it was orphaned (results never came back). I'm scheduling an immediate check of the service...
The critical problem is: after that, Nagios does not run any check anymore. As a workaround, I have to set up an event handler to restart Nagios whenever seeing this warning:
localhost.cfg
define service{
use logfile-service
host_name localhost
service_description nagios_orphaned
check_command check_nagios_orphaned
event_handler restart_nagios
contact_groups admin
}
commands.cfg
define command {
command_name check_nagios_orphaned
command_line sudo $USER2$/check_logfiles --tag=orphaned --logfile=/usr/local/nagios/var/nagios.log --warningpattern="looks like it was orphaned"
}
define command {
command_name restart_nagios
command_line $USER1$/eventhandlers/restart_nagios.sh $SERVICESTATE$
}
restart_nagios.sh
#!/bin/bash
case "$1" in
OK)
;;
WARNING)
/usr/bin/screen -S nagios -d -m sudo /etc/init.d/nagios restart
;;
UNKNOWN)
;;
CRITICAL)
;;
esac
exit 0
I've been trying to update the Nagios to the latest version:
# nagios -V
Nagios Core 3.5.0
Copyright (c) 2009-2011 Nagios Core Development Team and Community Contributors
Copyright (c) 1999-2009 Ethan Galstad
Last Modified: 03-15-2013
License: GPL
but still get this warning.
The first result when Googling is: http://support.nagios.com/wiki/index.php/Nagios_XI:FAQs#Check_Services_Being_Orphaned
but I'm sure there is only one (parent) process running:
# ps -ef | grep '/usr/local/nagios/bin/nagio[s]'
nagios 8956 15155 0 18:08 ? 00:00:00 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg
nagios 8957 15155 0 18:08 ? 00:00:00 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg
nagios 15155 1 5 14:09 ? 00:13:47 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg
Moreover, I don't see the Resource temporarily unavailable
error in the log file, so the ulimit
restrictions possibility can be excluded.
The embedded Perl interpreter was already disabled:
enable_embedded_perl=0
use_embedded_perl_implicitly=0
Is there any other causes?
PS: I'm running Nagios on a Xen HVM:
# virt-what
xen
xen-hvm
UPDATE Tue Apr 16 22:07:09 ICT 2013
Search for this warning in the source code directory, I found:
# grep -lr 'looks like it was orphaned' nagios-3.5.0
/nagios-3.5.0/base/checks.o
/nagios-3.5.0/base/nagios
/nagios-3.5.0/base/checks.c
and this is the check_for_orphaned_services
function:
/* check for services that never returned from a check... */
void check_for_orphaned_services(void) {
service *temp_service = NULL;
time_t current_time = 0L;
time_t expected_time = 0L;
log_debug_info(DEBUGL_FUNCTIONS, 0, "check_for_orphaned_services()\n");
/* get the current time */
time(¤t_time);
/* check all services... */
for(temp_service = service_list; temp_service != NULL; temp_service = temp_service->next) {
/* skip services that are not currently executing */
if(temp_service->is_executing == FALSE)
continue;
/* determine the time at which the check results should have come in (allow 10 minutes slack time) */
expected_time = (time_t)(temp_service->next_check + temp_service->latency + service_check_timeout + check_reaper_interval + 600);
/* this service was supposed to have executed a while ago, but for some reason the results haven't come back in... */
if(expected_time < current_time) {
/* log a warning */
logit(NSLOG_RUNTIME_WARNING, TRUE, "Warning: The check of service '%s' on host '%s' looks like it was orphaned (results never came back). I'm scheduling an immediate check of the service...\n", temp_service->description, temp_service->host_name);
log_debug_info(DEBUGL_CHECKS, 1, "Service '%s' on host '%s' was orphaned, so we're scheduling an immediate check...\n", temp_service->description, temp_service->host_name);
/* decrement the number of running service checks */
if(currently_running_service_checks > 0)
currently_running_service_checks--;
/* disable the executing flag */
temp_service->is_executing = FALSE;
/* schedule an immediate check of the service */
schedule_service_check(temp_service, current_time, CHECK_OPTION_ORPHAN_CHECK);
}
}
return;
}
Update at: Thu Apr 18 22:32:19 ICT 2013
Just to confirm, I have edited the source code to add the value of expected_time
and current_time
to the log file. What I get is:
[1366294608] expected_time: 'Thu Apr 18 21:16:36 2013
', current_time: 'Thu Apr 18 21:16:48 2013
' - Warning: The check of service 'Check_MK' on host 'xx' looks like it was orphaned (results never came back). I'm scheduling an immediate check of the service...
Re-reading the log file, I see an important message:
[1366218303] Warning: A system time change of 0d 0h 0m 1s (backwards in time) has been detected. Compensating...
Looks like Xen is the culprit.