Nagios Support Forum

Dear Box,

Below are the result:

[root@ccnagios01 libexec]# ./check_nrpe -H 192.168.38.144 -c nagios_memory
log from client:
May 31 17:48:01 rhel64-02 nrpe[32592]: Connection from 192.168.38.142 port 4290
May 31 17:48:01 rhel64-02 nrpe[32592]: Host address is in allowed_hosts
May 31 17:48:01 rhel64-02 nrpe[32592]: Handling the connection...
May 31 17:48:01 rhel64-02 nrpe[32592]: Host is asking for command 'nagios_memory' to be run...
May 31 17:48:01 rhel64-02 nrpe[32592]: Running command: /etc/nagios/nrpe.d/check_mem -uC -w 70 -c 90
May 31 17:48:01 rhel64-02 nrpe[32592]: Command completed with return code 3 and output:
May 31 17:48:01 rhel64-02 nrpe[32592]: Return Code: 3, Output: NRPE: Unable to read output
May 31 17:48:01 rhel64-02 nrpe[32592]: Connection from ▒Q{▒#177 closed.

[root@ccnagios01 libexec]# ./check_nrpe -H 192.168.38.144 -c nagios_cpu
log from client:
May 31 17:48:08 rhel64-02 nrpe[32596]: Connection from 192.168.38.142 port 6850
May 31 17:48:08 rhel64-02 nrpe[32596]: Host address is in allowed_hosts
May 31 17:48:08 rhel64-02 nrpe[32596]: Handling the connection...
May 31 17:48:08 rhel64-02 nrpe[32596]: Host is asking for command 'nagios_cpu' to be run...
May 31 17:48:08 rhel64-02 nrpe[32596]: Running command: /etc/nagios/nrpe.d/nagios_cpu.sh
May 31 17:48:10 rhel64-02 nrpe[32596]: Command completed with return code 0 and output: OK #012 user: 0%, system: 0%, iowait: 0%, idle: 100% #012 | cpu_user=0%;70;90; cpu_sys=0%;70;90; cpu_iowait=0%;70;90; cpu_idle=100%;
May 31 17:48:10 rhel64-02 nrpe[32596]: Return Code: 0, Output: OK #012 user: 0%, system: 0%, iowait: 0%, idle: 100% #012 | cpu_user=0%;70;90; cpu_sys=0%;70;90; cpu_iowait=0%;70;90; cpu_idle=100%;
May 31 17:48:10 rhel64-02 nrpe[32596]: Connection from ▒Q{▒#177 closed.


Thanks,
Kelvin

It could be that the nrpe account on the remote server is set to /sbin/nologin and that could cause the plugin to not function.
Ca you edit the /etc/passwd file and change this line from to Also, can you edit the nrpe.cfg file and change your command from to Make sure you restart the daemon that controls the startup of the nrpe agent so it will reload the changes.

Dear tgriep,

I modify the passwd file and nrpe.cfg. We also restarted the service.
[root@rhel64-02 ~]# cat /etc/passwd | grep nrpe
nrpe497:498:NRPE user for the NRPE service:/var/run/nrpe:/bin/bash

[root@rhel64-02 ~]# cat /etc/nagios/nrpe.cfg | grep memory
command[nagios_memory]=/etc/nagios/nrpe.d/check_mem -u -C -w 70 -c 90

However, the output is still same
[root@ccnagios01 libexec]# ./check_nrpe -H 192.168.38.144 -c nagios_memory
NRPE: Unable to read output

Jun 1 09:35:51 rhel64-02 nrpe[5536]: Connection from 192.168.38.142 port 15342
Jun 1 09:35:51 rhel64-02 nrpe[5536]: Host address is in allowed_hosts
Jun 1 09:35:51 rhel64-02 nrpe[5536]: Handling the connection...
Jun 1 09:35:51 rhel64-02 nrpe[5536]: Host is asking for command 'nagios_memory' to be run...
Jun 1 09:35:51 rhel64-02 nrpe[5536]: Running command: /etc/nagios/nrpe.d/check_mem -u -C -w 70 -c 90
Jun 1 09:35:51 rhel64-02 nrpe[5536]: Command completed with return code 3 and output:
Jun 1 09:35:51 rhel64-02 nrpe[5536]: Return Code: 3, Output: NRPE: Unable to read output
Jun 1 09:35:51 rhel64-02 nrpe[5536]: Connection from closed.

Thanks,
Kelvin

Can you login to the remote host, run the following commands and post the output?

chmod 777 /etc/nagios/nrpe.d/check_mem
su nrpe
/etc/nagios/nrpe.d/check_mem -u -C -w 70 -c 90
echo $?
getenforce

Dear tgriep,

Below are information for you:
[root@rhel64-02 ~]# cat /etc/passwd | grep nrpe
nrpe497:498:NRPE user for the NRPE service:/var/run/nrpe:/bin/bash
[root@rhel64-02 ~]# cat /etc/nagios/nrpe.cfg | grep memory
#command[nagios_memory]=/etc/nagios/nrpe.d/nagios_memory.sh -w 70 -c 90
command[nagios_memory]=/etc/nagios/nrpe.d/check_mem -u -C -w 70 -c 90
command[nagios_guest_memory]=/etc/nagios/nrpe.d/nagios_guest_memory.sh
[root@rhel64-02 ~]# chmod 777 /etc/nagios/nrpe.d/check_mem
[root@rhel64-02 ~]# su nrpe
bash-4.1$ /etc/nagios/nrpe.d/check_mem -u -C -w 70 -c 90
OK - 5.6% (5551468 kB) used.|TOTAL=99005228KB;;;; USED=5551468KB;69303659;89104705;; FREE=93453760KB;;;; CACHES=92491656KB;;;;
bash-4.1$ echo $?
0
bash-4.1$ getenforce
Enforcing

Thanks,
Kelvin

cyberportnoc wrote:bash-4.1$ getenforce
Enforcing

This may be the cause of your problems.

This command will set SELinux to Permissive: Run the command, reboot the server and test.

Dear Box,

Any risk for set SELINUX to permissive

Please advise.

Thanks,
Kelvin

Nope, Permissive will just have it set to log everything, but not follow any actions.

Dear Box,

Any other way instead of disable selinux?

Please advise.
Since it is production server, it turn on selinux for long time.
So, any other way instead of disable selinux

Please advise.

No sorry, I do not know.