NRPE Check Differeneces

[easy2kent]

Hello,

Our setup is Nagios XI 2012R2.4 from a VMWare VM and are monitoring a Ubuntu Server. Now the server is monitoring services with the check_init_service command from NRPE. It can get the status of services installed by us but when it tries to get the status of a out of the box service like cron or ssh it gives the error: NRPE Unable to read output. Through some googling, I have found that it can be a permission issue sometimes or the command is not correct. Seeing as it works with different services, it seems as though these cannot be the issue. I am fairly new to monitoring Linux with Nagios so bear with me here.

Kent

[lmiltchev]

Can you show the actual command that you are running from the command line, along with the output of it? Example - you can have something similar to this:

Code: Select all

./check_nrpe -H <clinet ip> -c check_init_service -a 'ssh'

Also, show us the command definition (from the remote box). How was NRPE installed (from repo, source)? Did you use our documentation for installing the linux agent?

http://assets.nagios.com/downloads/nagi ... _Agent.pdf

[easy2kent]

Code: Select all

./check_nrpe -H <ip> -c check_init_service -a ssh
NRPE: Unable to read output

Code: Select all

./check_nrpe -H <ip> -c check_init_service -a haproxy
haproxy is running.

Command Definition:

Code: Select all

command[check_init_service]=/usr/lib/nagios/plugins/check_init_service $ARG1$

I used the documentation for installing the linux agent by using the apt-get commands.

The ssh, cron, and rsyslog checks worked before when I first installed the agent. I rebooted the remote machine and that is when they started happening.

Kent

[slansing]

Can you share your nrpe config file from:

Code: Select all

/etc/nagios/nrpe.d

Please block out IP's and passwords.

[easy2kent]

Code: Select all

#############################################################################
# Sample NRPE Config File 
# Written by: Ethan Galstad ([email protected])
# 
# Last Modified: 11-23-2007
#
# NOTES:
# This is a sample configuration file for the NRPE daemon.  It needs to be
# located on the remote host that is running the NRPE daemon, not the host
# from which the check_nrpe client is being executed.
#############################################################################


# LOG FACILITY
# The syslog facility that should be used for logging purposes.

log_facility=daemon



# PID FILE
# The name of the file in which the NRPE daemon should write it's process ID
# number.  The file is only written if the NRPE daemon is started by the root
# user and is running in standalone mode.

pid_file=/var/run/nagios/nrpe.pid



# PORT NUMBER
# Port number we should wait for connections on.
# NOTE: This must be a non-priviledged port (i.e. > 1024).
# NOTE: This option is ignored if NRPE is running under either inetd or xinetd

server_port=5666



# SERVER ADDRESS
# Address that nrpe should bind to in case there are more than one interface
# and you do not want nrpe to bind on all interfaces.
# NOTE: This option is ignored if NRPE is running under either inetd or xinetd

#server_address=127.0.0.1



# NRPE USER
# This determines the effective user that the NRPE daemon should run as.  
# You can either supply a username or a UID.
# 
# NOTE: This option is ignored if NRPE is running under either inetd or xinetd

nrpe_user=nagios



# NRPE GROUP
# This determines the effective group that the NRPE daemon should run as.  
# You can either supply a group name or a GID.
# 
# NOTE: This option is ignored if NRPE is running under either inetd or xinetd

nrpe_group=nagios



# ALLOWED HOST ADDRESSES
# This is an optional comma-delimited list of IP address or hostnames 
# that are allowed to talk to the NRPE daemon.
#
# Note: The daemon only does rudimentary checking of the client's IP
# address.  I would highly recommend adding entries in your /etc/hosts.allow
# file to allow only the specified host to connect to the port
# you are running this daemon on.
#
# NOTE: This option is ignored if NRPE is running under either inetd or xinetd

allowed_hosts=127.0.0.1
 


# COMMAND ARGUMENT PROCESSING
# This option determines whether or not the NRPE daemon will allow clients
# to specify arguments to commands that are executed.  This option only works
# if the daemon was configured with the --enable-command-args configure script
# option.  
#
# *** ENABLING THIS OPTION IS A SECURITY RISK! *** 
# Read the SECURITY file for information on some of the security implications
# of enabling this variable.
#
# Values: 0=do not allow arguments, 1=allow command arguments

dont_blame_nrpe=0



# COMMAND PREFIX
# This option allows you to prefix all commands with a user-defined string.
# A space is automatically added between the specified prefix string and the
# command line from the command definition.
#
# *** THIS EXAMPLE MAY POSE A POTENTIAL SECURITY RISK, SO USE WITH CAUTION! ***
# Usage scenario: 
# Execute restricted commmands using sudo.  For this to work, you need to add
# the nagios user to your /etc/sudoers.  An example entry for alllowing 
# execution of the plugins from might be:
#
# nagios          ALL=(ALL) NOPASSWD: /usr/lib/nagios/plugins/
#
# This lets the nagios user run all commands in that directory (and only them)
# without asking for a password.  If you do this, make sure you don't give
# random users write access to that directory or its contents!

# command_prefix=/usr/bin/sudo 



# DEBUGGING OPTION
# This option determines whether or not debugging messages are logged to the
# syslog facility.
# Values: 0=debugging off, 1=debugging on

debug=0



# COMMAND TIMEOUT
# This specifies the maximum number of seconds that the NRPE daemon will
# allow plugins to finish executing before killing them off.

command_timeout=60



# CONNECTION TIMEOUT
# This specifies the maximum number of seconds that the NRPE daemon will
# wait for a connection to be established before exiting. This is sometimes
# seen where a network problem stops the SSL being established even though
# all network sessions are connected. This causes the nrpe daemons to
# accumulate, eating system resources. Do not set this too low.

connection_timeout=300



# WEEK RANDOM SEED OPTION
# This directive allows you to use SSL even if your system does not have
# a /dev/random or /dev/urandom (on purpose or because the necessary patches
# were not applied). The random number generator will be seeded from a file
# which is either a file pointed to by the environment valiable $RANDFILE
# or $HOME/.rnd. If neither exists, the pseudo random number generator will
# be initialized and a warning will be issued.
# Values: 0=only seed from /dev/[u]random, 1=also seed from weak randomness

#allow_weak_random_seed=1



# INCLUDE CONFIG FILE
# This directive allows you to include definitions from an external config file.

#include=<somefile.cfg>



# INCLUDE CONFIG DIRECTORY
# This directive allows you to include definitions from config files (with a
# .cfg extension) in one or more directories (with recursion).

#include_dir=<somedirectory>
#include_dir=<someotherdirectory>



# COMMAND DEFINITIONS
# Command definitions that this daemon will run.  Definitions
# are in the following format:
#
# command[<command_name>]=<command_line>
#
# When the daemon receives a request to return the results of <command_name>
# it will execute the command specified by the <command_line> argument.
#
# Unlike Nagios, the command line cannot contain macros - it must be
# typed exactly as it should be executed.
#
# Note: Any plugins that are used in the command lines must reside
# on the machine that this daemon is running on!  The examples below
# assume that you have plugins installed in a /usr/local/nagios/libexec
# directory.  Also note that you will have to modify the definitions below
# to match the argument format the plugins expect.  Remember, these are
# examples only!


# The following examples use hardcoded command arguments...

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_memory]=/usr/lib/nagios/plugins/check_mem.sh 80 90


# The following examples allow user-supplied arguments and can
# only be used if the NRPE daemon was compiled with support for 
# command arguments *AND* the dont_blame_nrpe directive in this
# config file is set to '1'.  This poses a potential security risk, so
# make sure you read the SECURITY file before doing this.

#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 $ARG3$

#
# local configuration:
#	if you'd prefer, you can instead place directives here
include=/etc/nagios/nrpe_local.cfg

# 
# you can place your config snipplets into nrpe.d/
# only snipplets ending in .cfg will get included
include_dir=/etc/nagios/nrpe.d/

It is out of the box config, have not made any changes.

Thanks.

[slansing]

You need to edit the nrpe.cfg and add your XI server's IP to the section as I show below, and you should also switch dont_blame_nrpe to 1 as well if you plan on using arguments:

Code: Select all

allowed_hosts=127.0.0.1,nagiosxi.server.ip.address

Then restart xinetd on the remote host to effect the changes:

Code: Select all

service xinetd restart

[easy2kent]

Thanks for the quick reply. When I try to restart xinetd it appears xinetd does not exist. It says xinetd: unrecognized service. I have tried restarting nagios-nrpe-server and that restarts but does not solve the issue. This service could be for something completely different. I just guessed.

Kent

[slansing]

Do you know where the init file for nrpe is located on your system? All you need to do is call that and issue a restart command through it.

It shoulddddd be in:

Code: Select all

/etc/init.d/

[jdev]

I'm running into this exact problem. Figured since this topic went unanswered, I could reply here.

The remote host I am trying to monitor is Ubuntu 12.10 64 Bit. I installed the linux agent using the repo from the installing the ubuntu and debian agent doc.

The command that I am trying to run is as follows

Code: Select all

./check_nrpe -H <remote host IP> -c check_init_service -a cron

I get in return:

Code: Select all

NRPE: Unable to read output

My nrpe.cfg file is stock save for 3 edits.

1) I added the IP address of my nagiosxi server for allowed_hosts
2) I uncommented the check_disk command
3) I added in the check_init_service command as command[check_init_service]=/usr/lib/nagios/plugins/check_init_service $ARG1$

Whats odd is that on a 32 bit Ubuntu 12.10 server, I installed the nagios-agent and the same commands work fine.

If there was a solution found for this, but just not posted, I'd love to try and implement it on my end so I can get cron and SSH checks working for this host.

[abrist]

NRPE: Unable to read output

This error is usually due to path issues. See the following document (section VII):
http://assets.nagios.com/downloads/nagi ... utions.pdf
On the remote system, what is the output of:

Code: Select all

ls -la /usr/lib/nagios/plugins