Nagios Support Forum

In Nagios server GUI. Getting below error for Remote servers. For alerts CPU, FTP,SSH.
No output on stdout) stderr: execvp(/usr/local/nagios/libexec/check_nrpe, ...) failed. errno is 2: No such file or directory

Hello @dheerushops,

The plugin is missing for some reason, perhaps in the wrong path. What is the output of the following commands?

Verify the plugin is in the right location: Check the permissions:

[root@nagiosserver ~]# find / -name check_nrpe
/tmp/nrpe-2.15/nrpe-2.15/src/check_nrpe
/usr/local/nagios/libexec/check_nrpe
[root@nagiosserver ~]# ls -l /usr/local/nagios/libexec/check_nrpe
-rwxr-xr-x 1 root root 76785 Dec 6 08:52 /usr/local/nagios/libexec/check_nrpe
[root@nagiosserver ~]#

Given output is from Nagios monitoring server

Below output is from nagios client host.

[root@nagioshost~]# find / -name check_nrpe
/usr/local/nagios/libexec/check_nrpe
/root/nagios/nrpe-2.15/src/check_nrpe
[root@nagioshost~]#
[root@nagioshost~]# ls -l /usr/local/nagios/libexec/check_nrpe
-rwxrwxr-x 1 nagios nagios 76777 Dec 3 13:21 /usr/local/nagios/libexec/check_nrpe
[root@nagioshost~]#

Hello,

This looks like the problem. The permissions on check_nrpe are set to root on the Nagios server.

/usr/local/nagios/libexec/check_nrpe
[root@nagiosserver ~]# ls -l /usr/local/nagios/libexec/check_nrpe
-rwxr-xr-x 1 root root 76785 Dec 6 08:52 /usr/local/nagios/libexec/check_nrpe

Run the following to corret and try once more.

For Nagios host getting below errors in Nagios monitoring tool.
nagioshost


FTP Monitoring

CRITICAL 12-11-2019 08:45:13 7d 19h 43m 3s 3/3 NRPE: Command 'check_ftp' not defined

SSH Monitoring

CRITICAL 12-11-2019 08:46:28 7d 19h 41m 48s 3/3 NRPE: Command 'check_ssh' not defined

Total Processes

CRITICAL 12-11-2019 08:47:43 7d 19h 40m 33s 3/3 PROCS CRITICAL: 263 processes

It seems like the 'check_ftp' and 'check_ssh' commands are not defined in nrpe.cfg on the client machine... You will have to define them on remote box, and restart the nrpe service. Then, you can run your checks again from the command line on the nagios server to see if the issue has been resolved.

I have added entries in file " /usr/local/nagios/etc/services.cfg"

define service{
use generic-service
host_name nagioshost
service_description SSH Monitoring
check_command check_nrpe!check_ssh
}

define service{
use generic-service
host_name nagioshost
service_description FTP Monitoring
check_command check_nrpe!check_ftp

Well, you defined you services on the nagios server, but you haven't defined you commands on the remote machine (the host that you are monitoring)...

Here's an example of a command definition that can be placed in your nrpe.cfg file on the client machine: After saving the file, and restarting nrpe on the remote box, so that changes can take effect: you can test your check by running the following command on the nagios server: In this example, you are passing 2 arguments - FTP server's IP address and a port number.

Example: Bottom line: when you use check_nrpe you pass your command with the "-c" flag. The command is defined on the remote box (host that you are monitoring). You pass arguments if needed, using the "-a" flag. Does this make sense?