Nagios and nrpe configuration

Support forum for Nagios Core, Nagios Plugins, NCPA, NRPE, NSCA, NDOUtils and more. Engage with the community of users including those using the open source solutions.
Locked
aramisbackwards
Posts: 13
Joined: Tue Nov 29, 2016 1:48 am

Nagios and nrpe configuration

Post by aramisbackwards »

Using CentOS7

I have a basic setup. One server and one remote, with Nagios and NRPE installed on the server, and NRPE installed on the remote.

Forgetting about the web interface, I'm trying to run everything from the command-line so that things are easier to understand

On the Server (Nagios + NRPE)

Code: Select all

[centos@nagios-server ~]$ /usr/local/nagios/libexec/check_nrpe -H 127.0.0.1 -c check_users
USERS OK - 1 users currently logged in |users=1;5;10;0
[centos@nagios-server ~]$ /usr/local/nagios/libexec/check_nrpe -H 127.0.0.1 
NRPE v3.0.1

[centos@nagios-server ~]$ systemctl status nagios && systemctl status nrpe
nagios.service - LSB: Starts and stops the Nagios monitoring server
   Loaded: loaded (/etc/rc.d/init.d/nagios)
   Active: active (running) since Tue 2016-11-29 06:47:44 UTC; 8min ago
  Process: 1116 ExecStart=/etc/rc.d/init.d/nagios start (code=exited, status=0/SUCCESS)
   CGroup: /system.slice/nagios.service
           ├─1172 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg
           ├─1175 /usr/local/nagios/bin/nagios --worker /usr/local/nagios/var/rw/nagios.qh
           ├─1176 /usr/local/nagios/bin/nagios --worker /usr/local/nagios/var/rw/nagios.qh
           ├─1177 /usr/local/nagios/bin/nagios --worker /usr/local/nagios/var/rw/nagios.qh
           ├─1178 /usr/local/nagios/bin/nagios --worker /usr/local/nagios/var/rw/nagios.qh
           └─1180 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg

nrpe.service - Nagios Remote Program Executor
   Loaded: loaded (/usr/lib/systemd/system/nrpe.service; enabled)
   Active: active (running) since Tue 2016-11-29 06:47:44 UTC; 8min ago
     Docs: http://www.nagios.org/documentation
 Main PID: 1114 (nrpe)
   CGroup: /system.slice/nrpe.service
           └─1114 /usr/local/nagios/bin/nrpe -c /usr/local/nagios/etc/nrpe.cfg -f
On the remote host (NRPE only)

Code: Select all

[centos@sinjihn-test ~]$ /usr/local/nagios/libexec/check_nrpe -H 127.0.0.1 -c check_users
USERS OK - 2 users currently logged in |users=2;5;10;0
[centos@sinjihn-test ~]$ /usr/local/nagios/libexec/check_nrpe -H 127.0.0.1
NRPE vnrpe-3.0
[centos@sinjihn-test ~]$ systemctl status nrp
nrp.service
   Loaded: not-found (Reason: No such file or directory)
   Active: inactive (dead)

[centos@sinjihn-test ~]$ systemctl status nrpe
nrpe.service - Nagios Remote Program Executor
   Loaded: loaded (/usr/lib/systemd/system/nrpe.service; disabled)
   Active: active (running) since Tue 2016-11-29 06:09:54 UTC; 47min ago
     Docs: http://www.nagios.org/documentation
  Process: 2347 ExecStopPost=/bin/rm -f /usr/local/nagios/var/nrpe.pid (code=exited, status=0/SUCCESS)
 Main PID: 2350 (nrpe)
   CGroup: /system.slice/nrpe.service
           └─2350 /usr/local/nagios/bin/nrpe -c /usr/local/nagios/etc/nrpe.cfg -f
On the server

Code: Select all

[centos@nagios-server ~]$ /usr/local/nagios/libexec/check_nrpe -H remote-ip -c check_users
CHECK_NRPE STATE CRITICAL: Socket timeout after 10 seconds.
[centos@nagios-server ~]$ /usr/local/nagios/libexec/check_nrpe -H remote-ip -t 60 -c check_users
CHECK_NRPE STATE CRITICAL: Socket timeout after 60 seconds.
[centos@nagios-server ~]$ sudo cat /usr/local/nagios/etc/servers/definitions.cfg 
define host {
	use 				linux-server
	host_name                       nagios-host-1
        hostgroups                      nagios-hosts
        alias                           OpenStack-Nagios-H1
        address                         remote-ip-address
        max_check_attempts              5
        check_period                    24x7
        check_interval                  1
        notification_interval           30
        notification_period             24x7
	check_command 			check-host-alive
}

define host {
	use 				linux-server
        host_name                       nagios-host-2
        hostgroups                      nagios-hosts
        alias                           OpenStack-Nagios-H2
        address                         remote-ip-address
        max_check_attempts              5
        check_period                    24x7
        check_interval                  1
        notification_interval           30
        notification_period             24x7
        check_command                   check-host-alive
}

define hostgroup {
	hostgroup_name 			nagios-hosts
	alias 				Nagios-Remote-Hosts

}

define service {
	hostgroup_name 			nagios-hosts
	service_description 		CHECK PING
	check_command 			check_ping!100.0,20%!500.0,60%
	check_interval 			1
	check_period 			24x7
	retry_interval 			1
	notification_interval 		30
	notification_period 		24x7
	max_check_attempts 		5
	use 				generic-service
}

define service {
        hostgroup_name                  nagios-hosts
        service_description             CHECK HTTP
        check_command                   check_http
        check_interval                  1
        check_period                    24x7
        retry_interval                  1
        notification_interval           30
        notification_period             24x7
        max_check_attempts              5
	use 				generic-service

}
define service {
        hostgroup_name                  nagios-hosts
        service_description             CHECK NRPE TEST WITH HTTP
        check_command                   check_nrpe!check_http
        check_interval                  1
        check_period                    24x7
        retry_interval                  1
        notification_interval           30
        notification_period             24x7
        max_check_attempts              5
	use 				generic-service

}
What exactly is going on here? If you need any more configuration information I can update it, but I'm at a loss of understanding how the check_nrpe plugin works in relation to nagios. I've been trying to figure this issue out for days, referencing almost every instance of this problem that's appeared on these forums.

For more reference, these nodes are all virtual, with firewalld and httpd installed. I unblocked port 5666/tcp and 80/tcp on all servers, as well as putting selinux into permissive mode.

Code: Select all

nmap -v localhost

Starting Nmap 6.40 ( http://nmap.org ) at 2016-11-29 07:09 UTC
Initiating Ping Scan at 07:09
Scanning localhost (127.0.0.1) [2 ports]
Completed Ping Scan at 07:09, 0.00s elapsed (1 total hosts)
Initiating Connect Scan at 07:09
Scanning localhost (127.0.0.1) [1000 ports]
Discovered open port 25/tcp on 127.0.0.1
Discovered open port 111/tcp on 127.0.0.1
Discovered open port 80/tcp on 127.0.0.1
Discovered open port 22/tcp on 127.0.0.1
Discovered open port 5666/tcp on 127.0.0.1
Completed Connect Scan at 07:09, 0.01s elapsed (1000 total ports)
Nmap scan report for localhost (127.0.0.1)
Host is up (0.00026s latency).
Other addresses for localhost (not scanned): 127.0.0.1
Not shown: 995 closed ports
PORT     STATE SERVICE
22/tcp   open  ssh
25/tcp   open  smtp
80/tcp   open  http
111/tcp  open  rpcbind
5666/tcp open  nrpe
Last edited by aramisbackwards on Tue Nov 29, 2016 7:45 pm, edited 1 time in total.
Top
dwhitfield
Former Nagios Staff
Posts: 4583
Joined: Wed Sep 21, 2016 10:29 am
Location: NoLo, Minneapolis, MN
Contact:
Contact dwhitfield

Re: Nagios and nrpe configuration

Post by dwhitfield »

aramisbackwards wrote:I've been trying to figure this issue out for days, referencing almost every instance of this problem that's appeared on these forums.
It seems like you've been thorough (thanks for the detail!), but have you been using https://assets.nagios.com/downloads/nag ... e/NRPE.pdf? Also, there's this troubleshooting document: https://assets.nagios.com/downloads/nag ... utions.pdf. Those may be easier than trying to parse out the real issues on forum threads.

I think the immediate issue is that you do not have the same NRPE versions: 3.0 versus 3.0.1. I haven't tested this with 3, but with 2.x SOP was to have the versions match. Please let us know if that does not resolve your issue.
Top
rkennedy
Posts: 6579
Joined: Mon Oct 05, 2015 11:45 am

Re: Nagios and nrpe configuration

Post by rkennedy »

It looks like you ran an nmap, but against localhost, could you please run it FROM the Nagios machine, against the client server?

Code: Select all

nmap 220.159.28.94
Judging from the error, there is a firewall somewhere.
Former Nagios Employee
Top
aramisbackwards
Posts: 13
Joined: Tue Nov 29, 2016 1:48 am

Re: Nagios and nrpe configuration

Post by aramisbackwards »

rkennedy wrote:It looks like you ran an nmap, but against localhost, could you please run it FROM the Nagios machine, against the client server?

Code: Select all

nmap 220.159.28.94
Judging from the error, there is a firewall somewhere.
Yup, this was the issue. As it turns out, the firewall in the OS was only one layer - even after opening ports on that there was still a physical firewall blocking 5666 that I had to open somewhere else on some GUI.

After that everything works fine. Sorry for troubling you all.
dwhitfield wrote:
aramisbackwards wrote:I've been trying to figure this issue out for days, referencing almost every instance of this problem that's appeared on these forums.
It seems like you've been thorough (thanks for the detail!), but have you been using https://assets.nagios.com/downloads/nag ... e/NRPE.pdf? Also, there's this troubleshooting document: https://assets.nagios.com/downloads/nag ... utions.pdf. Those may be easier than trying to parse out the real issues on forum threads.

I think the immediate issue is that you do not have the same NRPE versions: 3.0 versus 3.0.1. I haven't tested this with 3, but with 2.x SOP was to have the versions match. Please let us know if that does not resolve your issue.
This wasn't an issue actually, but I remember when using 2.15 vs 3.0 it was actually. I'll definitely save these pdfs for future reference though, thanks.


You can close this topic.
Top
dwhitfield
Former Nagios Staff
Posts: 4583
Joined: Wed Sep 21, 2016 10:29 am
Location: NoLo, Minneapolis, MN
Contact:
Contact dwhitfield

Re: Nagios and nrpe configuration

Post by dwhitfield »

aramisbackwards wrote:This wasn't an issue actually, but I remember when using 2.15 vs 3.0 it was actually.
Thanks for the update on that! Glad everything is working for you. I'll close the thread.
Top
Locked

Return to “Open Source Nagios Projects”