Raspbian NRPE - Received 0 bytes from daemon

[WillemDH]

Trying to monitor a Raspberry, but stuck on

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/usr/local/nagios/libexec/check_nrpe -H f1reberry.outsideit.net -t 30 -p 5666 -c check_users -a '-w 2 -c 5'
CHECK_NRPE: Received 0 bytes from daemon.  Check the remote server logs for error messages.

dont_blame_nrpe is set to 1 in the nrpe.cfg config file:

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cat /etc/nagios/nrpe.cfg | grep blame
dont_blame_nrpe=1

NRPE is listening:

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/usr/local/nagios/libexec/check_nrpe -H f1reberry.outsideit.net -p 5666
NRPE v2.15

Without args I get a proper help message:

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/usr/local/nagios/libexec/check_nrpe -H f1reberry.outsideit.net -t 30 -p 5666 -c check_users
check_users: Warning threshold must be a positive integer
Usage:
check_users -w <users> -c <users>

So why could this not be working when using args and dont_blame_nrpe set to 1? I saw some threads about compiling nrpe at installation by configuring the binary with –enable-command-args. But there must be a way to enable this post installation?

I installed nrpe with

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apt-get install nagios-nrpe-server,nagios-plugins

This is my complete nrpe.cfg:

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log_facility=daemon
pid_file=/var/run/nagios/nrpe.pid
server_port=5666
#server_address=127.0.0.1
nrpe_user=nagios
nrpe_group=nagios
allowed_hosts=127.0.0.1,212.71.234.84
dont_blame_nrpe=1
allow_bash_command_substitution=0
# command_prefix=/usr/bin/sudo
debug=0
command_timeout=60
connection_timeout=300
#allow_weak_random_seed=1
#include=<somefile.cfg>
#include_dir=<somedirectory>
#include_dir=<someotherdirectory>

#command[check_users]=/usr/lib/nagios/plugins/check_users -w 5 -c 10
#command[check_load]=/usr/lib/nagios/plugins/check_load -w 15,10,5 -c 30,25,20
#command[check_hda1]=/usr/lib/nagios/plugins/check_disk -w 20% -c 10% -p /dev/hda1
#command[check_zombie_procs]=/usr/lib/nagios/plugins/check_procs -w 5 -c 10 -s Z
#command[check_total_procs]=/usr/lib/nagios/plugins/check_procs -w 150 -c 200
command[check_users]=/usr/lib/nagios/plugins/check_users -w $ARG1$ -c $ARG2$
command[check_load]=/usr/lib/nagios/plugins/check_load -w $ARG1$ -c $ARG2$
command[check_disk]=/usr/lib/nagios/plugins/check_disk -w $ARG1$ -c $ARG2$ -p $ARG3$
command[check_procs]=/usr/lib/nagios/plugins/check_procs -w $ARG1$ -c $ARG2$ -s $ARG3$

include=/etc/nagios/nrpe_local.cfg
include_dir=/etc/nagios/nrpe.d/

NRPE has been restarted:

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/etc/init.d/nagios-nrpe-server restart
[ ok ] Restarting nagios-nrpe-server (via systemctl): nagios-nrpe-server.service.

Any help is welcome.

[hsmith]

I haven't used the NRPE package from apt on my Pi, but I do know if you don't compile with enable command args, it's generally not going to allow arguments. AFAIK the answer has always been recompile. Even if you enable dont_blame_nrpe=1, it's still going to need that flag set at the time of being compiled.

[WillemDH]

I'm guessing you followed this procedure?

https://www.raspberrypi.org/forums/view ... 6&t=105002

I basically followed this one:

https://viewsby.wordpress.com/2013/02/1 ... ntudebian/

So why on earth would the nrpe package from apt not install with –enable-command-args? Would there be some way to specify that while installing? It seems very weird to me that there would be no way to do. I'm automating the whole install procedure with an unattended net installer by the way. https://github.com/willemdh/raspbian-ua-netinst

Here is my post-install.txt and naf_raspbian_config.sh which runs at first login.

https://github.com/willemdh/naf_linux_raspbian_config

If I can just install the apt packages, it's easier by just specifying the required packages in installer-onfig.txt:

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packages=apt-utils,vim,aptitude,apt-file,git,mlocate,bc,sysstat,dos2unix,iptables,xrdp,sudo,gcc,libssl-dev,build-essential,nagios-nrpe-server,nagios-plugins

Else I have to:

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-WriteLog Verbose Info "- Downloading NRPE"
 -wget https://github.com/NagiosEnterprises/nrpe/archive/nrpe-2-15.tar.gz -O /tmp/nrpe-2-15.tar.gz > /dev/null 2>&1
 -WriteLog Verbose Info "- Unpacking NRPE"
 -tar -zxvf /tmp/nrpe-2-15.tar.gz -C /usr/local/nagios > /dev/null 2>&1
 -mv /usr/local/nagios/nrpe-nrpe-2-15/ /usr/local/nagios/nrpe-2-15/
 -WriteLog Verbose Info "- Creating symbolic link so NRPE can find the ARM SSL library"
 -sudo ln -s /usr/lib/arm-linux-gnueabihf/libssl.so /usr/lib/libssl.so
 -WriteLog Verbose Info "- Build NRPE - Configure"
 -/usr/local/nagios/nrpe-2-15/configure --with-ssl=/usr/bin/openssl --with-ssl-lib=/usr/lib/arm-linux-gnueabihf
 -WriteLog Verbose Info "- Build NRPE - Adding nagios user"
 -useradd nagios
 -WriteLog Verbose Info "- Build NRPE - make all"
 -make all
 -WriteLog Verbose Info "- Build NRPE - make install"
 -make install
 -WriteLog Verbose Info "- Build NRPE - make install-plugin"
 -make install-plugin
 -WriteLog Verbose Info "- Build NRPE - make install-daemon"
 -make install-daemon

So in what step would I have to set –enable-command-args?

Grtz

[hsmith]

I'm guessing you followed this procedure?

I don't actually have NRPE running on my Pi. I'll go ahead and give it a go and let you know though.

So why on earth would the nrpe package from apt not install with –enable-command-args? Would there be some way to specify that while installing? It seems very weird to me that there would be no way to do. I'm automating the whole install procedure with an unattended net installer by the way. https://github.com/willemdh/raspbian-ua-netinst

That command is considered insecure by many, as you can pass some nasty stuff to NRPE if you're not careful with your settings. Hardcoding what commands can be passed is safer than trying to limit what can't. Whitelist vs blacklist.

Let me test the NRPE available on Raspbian and get back to you. I may not have time today to test this, and I'm going out of town for the rest of the week, so it may be Sunday when you hear back. I won't forget about you though

[WillemDH]

Holden, did you have the chance to test the package? Grtz

[hsmith]

Hey Willem, I got it installed, but when I went to work on it today(sorry, it's been a hectic week again), I realize I don't have port forwarding for 5666 on my home network, nor do I have access to my router interface to fix that from outside my home network. I'll fix it up tonight.

[WillemDH]

Np, take your time. Attached my pot forwarding router config.

[hsmith]

Got my port forwarding set up. I've been unsuccessful in all attempts to enable command arguments so far using the package nagios-nrpe-server package from apt. I'll look around apt and see if there is another package, plus see if I can find out who is the maintainer of that package(I may be unsuccessful in both of these attempts, doesn't hurt to try though.) I have a feeling if you want to use apt to install nrpe, you might be stuck without command arguments. It might be worthwhile to use some automation to push out a new nrpe.cfg file with the commands you want instead of compiling on each machine.

[WillemDH]

Holden,

It would seem perfectly logically to have some way to allow arguments after installation imho? I can't see a reason why this would not be technically possible..

Grtz

[hsmith]

I agree with you. I'll talk to @jfrickson. The thing is though, if we're not the maintainers of that package on apt, we can't do a thing about it. The version on there is already 2 versions behind. I've reached out to our developers to try to find out who the maintainer of the package is, I'm still waiting for a response.