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NRPE: Unable to read output in Solaris 10

Posted: Tue Sep 01, 2015 10:12 am
by Maorzv
HI Everyone,

I am new in Nagios, and my company asked me to test Nagiosxi.

So far it is not that hard, but I have a problem when I want to monitor Solaris 10 server with following services:
Users
Load
Disk Usage
Sendmail
Rest of the services are working well.

The services that don't work with NRPE, work when I try them alone (without NRPE), for example:

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 <11:02:28 root@local/usr/local/nagios/libexec>$ ./check_users -w 5 -c 10
USERS OK - 2 users currently logged in |users=2;5;10;0
<11:04:46 root@local /usr/local/nagios/libexec>$ ./check_nrpe -H server -n  -t 30 -c check_users -a '-w 5 -c 10'
NRPE: Unable to read output
 
I don't think it is a premission problem because I tried to run it as nagios user.

my nrpe.cfg file is:

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#############################################################################
# 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/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. Network addresses with a bit mask
# (i.e. 192.168.1.0/24) are also supported. Hostname wildcards are not currently 
# supported.
#
# 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



# BASH COMMAND SUBTITUTION
# This option determines whether or not the NRPE daemon will allow clients
# to specify arguments that contain bash command substitutions of the form
# $(...).  This option only works if the daemon was configured with both 
# the --enable-command-args and --enable-bash-command-substitution configure 
# script options.
#
# *** ENABLING THIS OPTION IS A HIGH SECURITY RISK! *** 
# Read the SECURITY file for information on some of the security implications
# of enabling this variable.
#
# Values: 0=do not allow bash command substitutions, 
#         1=allow bash command substitutions

allow_bash_command_substitution=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/local/nagios/libexec/check_users -w 5 -c 10
command[check_load]=/usr/local/nagios/libexec/check_load -w 15,10,5 -c 30,25,20
command[check_hda1]=/usr/local/nagios/libexec/check_disk -w 20% -c 10% -p /dev/hda1
command[check_zombie_procs]=/usr/local/nagios/libexec/check_procs -w 5 -c 10 -s Z
command[check_total_procs]=/usr/local/nagios/libexec/check_procs -w 150 -c 200 


# 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/local/nagios/libexec/check_users -w $ARG1$ -c $ARG2$
#command[check_load]=/usr/local/nagios/libexec/check_load -w $ARG1$ -c $ARG2$
#command[check_disk]=/usr/local/nagios/libexec/check_disk -w $ARG1$ -c $ARG2$ -p $ARG3$
#command[check_procs]=/usr/local/nagios/libexec/check_procs -w $ARG1$ -c $ARG2$ -s $ARG3$

Thanks for any help,
Maor

Re: NRPE: Unable to read output in Solaris 10

Posted: Tue Sep 01, 2015 10:45 am
by jolson
I am assuming you're using NRPE without SSL based on the '-n' in your command?

In your NRPE.cfg file:

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command[check_users]=/usr/local/nagios/libexec/check_users -w 5 -c 10
What this means is that NRPE will process the 'check_users' command definition and unpack it as 'check_users -w 5 -c 10' on the Solaris side. Try this from Nagios:

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./check_nrpe -H hostname -n -t 30 -c check_users
It's worth noting that you are not allowing the passage of arguments via NRPE. If you want to pass arguments, you need to modify the 'dont_blame_nrpe' directive:
# Values: 0=do not allow arguments, 1=allow command arguments

dont_blame_nrpe=0

Re: NRPE: Unable to read output in Solaris 10

Posted: Tue Sep 01, 2015 12:53 pm
by Maorzv
you right, I use NRPE without SSL (-n).

I changed dont_blame_nrpe to 1 (dont_blame_nrpe=1) so now I can use arguments.

I tried :

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<13:46:26 root@local /usr/local/nagios/libexec>$  ./check_nrpe -H server -t 30 -c check_load -n -a '-w 15,10,5 -c 30,20,1'
NRPE: Unable to read output

<13:52:51 root@local /usr/local/nagios/libexec>$ ./check_nrpe -H server -n -t 30 -c check_users
NRPE: Unable to read output

can it be a problem with the solaris 10 ?

Re: NRPE: Unable to read output in Solaris 10

Posted: Tue Sep 01, 2015 1:16 pm
by jdalrymple
Solaris 10 is a known working platform. That's not to say that there isn't a problem with your installation on Solaris 10, but we'll have to troubleshoot to find out.

Can you try running `check_nrpe -H 127.0.0.1 -n` on the Solaris box and see if that works? Also, you may wish to enable debugging in nrpe.cfg (on the Solaris box) then restart nrpe to see if anything useful pops up in the logs.

Re: NRPE: Unable to read output in Solaris 10

Posted: Tue Sep 01, 2015 1:19 pm
by tgriep
In addition to what jdalrymple requested, can you run the following and post the output here?

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 /usr/local/nagios/bin/nrpe -v
Also, if there are any files in the /etc/nrpe folder, can you upload those to this post?

Re: NRPE: Unable to read output in Solaris 10

Posted: Tue Sep 01, 2015 4:11 pm
by Maorzv
Thank you both for trying to help.

when I try:

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./check_nrpe -H 127.0.0.1 -n
I receive:

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NRPE v2.15
when:

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. /nrpe -V
receive:

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NRPE - Nagios Remote Plugin Executor

Copyright (c) 1999-2008 Ethan Galstad ([email protected])

Version: 2.15

Last Modified: 09-06-2013

License: GPL v2 with exemptions (-l for more info)

SSL/TLS Available: Anonymous DH Mode, OpenSSL 0.9.6 or higher required

TCP Wrappers Available
In addition, I just configured new wizard - postgres database, and now also the rest of the NRPE services status is:
NRPE: Unable to read output

but this time, they are under "warning" and not under "unhandled" as the services I mentioned above.

Again, rest of the services were ok before I configured psql.

Re: NRPE: Unable to read output in Solaris 10

Posted: Tue Sep 01, 2015 4:50 pm
by tgriep
On the Solaris system, can you edit the nrpe.cfg file and change the following from

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debug=0
to

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debug=1
Save it out and restart the NRPE daemon.

Then run this in the system and check the /var/log/syslog for any errors. Post the errors.

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./check_nrpe -H hostname -n -t 30 -c check_users
Can you describe the steps you took when you configured the wizard for the postgres database?

Re: NRPE: Unable to read output in Solaris 10

Posted: Tue Sep 01, 2015 5:04 pm
by jolson
In addition to what @tgriep has stated, I want to clarify a few things.

Let's say you run the following check from Nagios to your Solaris 10 box:

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./check_nrpe -H hostname -n -t 30 -c check_users
When your NRPE client (Solaris) receives the 'check_users' command, it will consult nrpe.cfg for a matching definition:
command[check_users]=/usr/local/nagios/libexec/check_users -w 5 -c 10
command[check_load]=/usr/local/nagios/libexec/check_load -w 15,10,5 -c 30,25,20
command[check_hda1]=/usr/local/nagios/libexec/check_disk -w 20% -c 10% -p /dev/hda1
command[check_zombie_procs]=/usr/local/nagios/libexec/check_procs -w 5 -c 10 -s Z
command[check_total_procs]=/usr/local/nagios/libexec/check_procs -w 150 -c 200
In this case, your Solaris box will then run '/usr/local/nagios/libexec/check_users -w 5 -c 10' on its own. Because of this, you do not need to add arguments to your check commands from Nagios. Does that make sense?

If you run:
/usr/local/nagios/libexec>$ ./check_nrpe -H server -n -t 30 -c check_users -a '-w 5 -c 10'

from Nagios XI to Solaris, your Solaris box will then run:

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/usr/local/nagios/libexec/check_users -w 5 -c 10 -a '-w 5 -c 10'
Which will fail. Just wanted to clarify how arguments work from Nagios to Solaris. Hope this helps!