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Re: What am I missing? (NRPE: Unable to read output)
Posted: Tue Apr 05, 2016 3:56 pm
by tgriep
I think the problem is with the ! in the output of the plugin. The ! is used as a delimiter in Nagios and that could cause the error.
Try replacing the check_mem on your system with the one in the link below and see if that works for you.
https://raw.githubusercontent.com/justi ... eck_mem.pl
Re: What am I missing? (NRPE: Unable to read output)
Posted: Tue Apr 05, 2016 4:02 pm
by aneah
lmiltchev wrote:What commands did you run in order to install Nagios Plugins and NRPE?
It is very strange that the nagios user is not available...
This account is currently not available.
What is the output of the following commands?
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grep nag /etc/passwd
grep nag /etc/group
grep "nrpe_" /path/to/the/nrpe.cfg
chage nagios -l
Directions to install were from here:
http://tecadmin.net/install-nrpe-on-centos-rhel/
Same directions were used on each server.
I found it odd too that nagios wasn't available, but that's also consistent with the other servers.
grep nag /etc/passwd:
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nagios:x:498:499::/var/spool/nagios:/sbin/nologin
grep nag /etc/group:
grep "nrpe_" /etc/nagios/nrpe.cfg:
chage nagios -l
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Last password change : Mar 08, 2016
Password expires : never
Password inactive : never
Account expires : never
Minimum number of days between password change : -1
Maximum number of days between password change : -1
Number of days of warning before password expires : -1
Re: What am I missing? (NRPE: Unable to read output)
Posted: Tue Apr 05, 2016 4:15 pm
by aneah
tgriep wrote:I think the problem is with the ! in the output of the plugin. The ! is used as a delimiter in Nagios and that could cause the error.
Try replacing the check_mem on your system with the one in the link below and see if that works for you.
https://raw.githubusercontent.com/justi ... eck_mem.pl
I had that one stored to use, just in case (though I think I got it from somewhere else). But anyway, I installed the check_mem.pl plugin. For grins, I also copied over the check_mem plugin from another server that is working fine. Both have the same owners/groups/privs as the rest of the plugins. Still same error after restarting NRPE.
Updated NRPE.cfg as such:
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#command[check_mem]=/usr/lib64/nagios/plugins/check_mem -f -w 20 -c 10
command[check_mem]=/usr/lib64/nagios/plugins/check_mem.pl -w 20 -c 10
Performed the restart of the NRPE service, still nothing.
If I run the /usr/lib64/nagios/plugins/check_mem.pl -w 20 -c 10 from the client, I get the following:
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<b>CRITICAL: Memory Usage (W> 20, C> 10): 99% <br>Swap Usage (W> 100, C> 100): 0%</b>|MemUsed=99%;20;10 SwapUsed=0%;100;100
Re: What am I missing? (NRPE: Unable to read output)
Posted: Tue Apr 05, 2016 4:40 pm
by hsmith
aneah wrote:
If I run the /usr/lib64/nagios/plugins/check_mem.pl -w 20 -c 10 from the client, I get the following:
What user did you run this as?
Re: What am I missing? (NRPE: Unable to read output)
Posted: Wed Apr 06, 2016 7:48 am
by aneah
hsmith wrote:aneah wrote:
If I run the /usr/lib64/nagios/plugins/check_mem.pl -w 20 -c 10 from the client, I get the following:
What user did you run this as?
root.
Re: What am I missing? (NRPE: Unable to read output)
Posted: Wed Apr 06, 2016 7:54 am
by aneah
hsmith wrote:aneah wrote:
If I run the /usr/lib64/nagios/plugins/check_mem.pl -w 20 -c 10 from the client, I get the following:
What user did you run this as?
I also managed to find a way to su the Nagios account. For future reference for others, use the following command:
I also ran the /usr/lib64/nagios/plugins/check_mem.pl -w 20 -c 10 as Nagios, from the client and obtained the same results as previously.
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<b>CRITICAL: Memory Usage (W> 20, C> 10): 99% <br>Swap Usage (W> 100, C> 100): 0%</b>|MemUsed=99%;20;10 SwapUsed=0%;100;100
Re: What am I missing? (NRPE: Unable to read output)
Posted: Wed Apr 06, 2016 1:11 pm
by hsmith
It looks like you have NRPE configured to run as the NRPE user instead of the nagios user, can you su to that user and try the check?
Re: What am I missing? (NRPE: Unable to read output)
Posted: Fri Apr 08, 2016 12:49 pm
by aneah
hsmith wrote:It looks like you have NRPE configured to run as the NRPE user instead of the nagios user, can you su to that user and try the check?
Exact same results as running as Nagios and root. In fact, the NRPE account gave the same error as the Nagios account and had to be run as I previously indicated.
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<b>CRITICAL: Memory Usage (W> 20, C> 10): 99% <br>Swap Usage (W> 100, C> 100): 0%</b>|MemUsed=99%;20;10 SwapUsed=0%;100;100
Also, NRPE is the same user in the NRPE.cfg file on all the other servers. Again, this is ONLY the check_mem plugin on one server. Others running on the same server all have the same owner, group, and permissions.
In fact, I just copied over the check_mem plugin and NRPE.cfg files from another server (where things were functioning fine) and restarted the nrpe process and no change.
I'll be doing an update and reboot on the machine tonight. I'm hoping that automagically fixes this.
Re: What am I missing? (NRPE: Unable to read output)
Posted: Fri Apr 08, 2016 12:54 pm
by hsmith
Here's hoping.
Something to do would be compare the output of a cat /proc/meminfo command on both your working servers and a non working server to see if there is some weird formatting the plugin could be tripping on.
Re: What am I missing? (NRPE: Unable to read output)
Posted: Sat Apr 09, 2016 1:13 am
by aneah
Officially resolved as of tonight.
Cause: At this point, just speculation.
Remedy: Updated RHEL from 6.6 to 6.7 on the client and rebooted. When the server came back up, the error was gone.