<table border width=100%> <tr valign=top> <td width=100% bgcolor=white>From: SCHAER Frederic <frederic.schaer <at> cea.fr> Subject: <a href="http://news.gmane.org/find-root.php?message_id=%3cEA04FF699CD5274E9EC52CB5EC0508707667A0%40DIODON.extra.cea.fr%3e" target=_top>nagios 3 host checks logic problem on some kernels/distros</a> Newsgroups: <a href=http://news.gmane.org/gmane.network.nagios.devel target=_top>MailScanner has detected a possible fraud attempt from "news.gmane.org" claiming to be gmane.network.nagios.devel</a> Date: 2007-09-10 16:17:30 GMT (1 week, 15 hours and 23 minutes ago) Hi, I think I identified a problem (but not and the solution) on the nagios 3 source tree… I tried with both the 3.0b3 and cvs HEAD source files and could not get rid of the problem. I’m running a 2.4.21 kernel on a RHEL3 box. What happens is that as soon as I start nagios 3, it starts eating all of the CPU. Stracing the nagios process shows this (and almost only this): gettimeofday({1189419621, 161574}, NULL) = 0 time([1189419621]) = 1189419621 time([1189419621]) = 1189419621 gettimeofday({1189419621, 183742}, NULL) = 0 gettimeofday({1189419621, 183780}, NULL) = 0 gettimeofday({1189419621, 183814}, NULL) = 0 time([1189419621]) = 1189419621 gettimeofday({1189419621, 184172}, NULL) = 0 gettimeofday({1189419621, 184326}, NULL) = 0 time([1189419621]) = 1189419621 time([1189419621]) = 1189419621 gettimeofday({1189419621, 184734}, NULL) = 0 gettimeofday({1189419621, 184861}, NULL) = 0 I tried stracing nagios on a Ubuntu feisty (7.04) box, and the output is much different : there are nanosleep calls… I tried activating and deactivating nanosleeps at nagios compile time, but this did not solve my problem. Having full debug, I have this kind of output at the nagios start : [1189438977.881574] [016.0] [pid=18234] Attempting to run scheduled check of host 'wn010': check options=0, latency=0.874000 [1189438977.881651] [001.0] [pid=18234] run_async_host_check_3x() [1189438977.881665] [016.0] [pid=18234] ** Running async check of host 'wn010'... [1189438977.881678] [001.0] [pid=18234] check_host_check_viability_3x() [1189438977.881691] [001.0] [pid=18234] check_time_against_period() [1189438977.881712] [001.0] [pid=18234] check_host_dependencies() [1189438977.881726] [016.1] [pid=18234] A check of this host is already being executed, so we'll pass for the moment... [1189438977.881739] [016.1] [pid=18234] Unable to run scheduled host check at this time If I run nagios just for 2 seconds and then hit CTRL+C, I still see this : >grep "A check of this host is already being executed" /var/log/nagios/nagios.debug | wc -l 971 >grep "Attempting to run scheduled check of host 'wn010'" /var/log/nagios/nagios.debug | wc -l 971 >grep "Attempting to run scheduled check of host" /var/log/nagios/nagios.debug | wc -l 971 I have 53 hosts defined, I don’t understand why nagios is checking ever and ever the same host… and why this is not happening on all systems. De-activating host checks magically “solves” the problem. I just found out that commenting hosts “check_command” caused this behaviour (with host_checks_enabled=true), and that defining a correct check_command prevented nagios from being so CPU hungry… Hope I helped… Cheers </table> Dear List, I can confirm the problem Frederic reported. I am using Nagios 3.0b3 on CentOS 4.4 After starting nagios, the process catches nearly 100 % CPU (See top-output below) Disableing hostchecks let the process return to normal values. As far as I can remember, the problem did not occour with nagios3.0a (but I can not verify at the moment) Tasks: 89 total, 3 running, 86 sleeping, 0 stopped, 0 zombie Cpu(s): 26.0% us, 1.3% sy, 0.0% ni, 72.6% id, 0.0% wa, 0.1% hi, 0.0% si Mem: 4041580k total, 1373844k used, 2667736k free, 60200k buffers Swap: 4192956k total, 0k used, 4192956k free, 1137348k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 28617 nagios 25 0 29756 10m 1056 R 96 0.3 17:12.48 nagios 1 root 16 0 4752 552 460 S 0 0.0 0:02.75 init 2 root RT 0 0 0 0 S 0 0.0 0:00.04 migration/0 Thomas P Please consider the environmental impact of needlessly printing this e-mail. <hr/>RSC Commercial Services OHG Wanheimer Straße 70, D-40468 Düsseldorf Registergericht: Düsseldorf, HRA 12655