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CentOS - Unable to monitor Redhat OS

Posted: Wed Feb 11, 2015 2:11 am
by timlee
Hi,

I am using a CentOS release 6.6 (Final) build OS as monitoring Server, and monitoring another linux server of the same build.
I did a manual installation of nagios using the package from http://assets.nagios.com/downloads/nagi ... est.tar.gz (according to the Nagios XI – Manual Installation Instructions guide), running on xinetd. I have no problems monitoring a windows server, however this is not the case with a linux sever.

I have also followed the Nagios XI - NRPE Troubleshooting and Common Solutions guide, but nothing helps.

Using the monitoring wizard, I have also, tried both options:

1) With SSL Encryption enabled - I have the error of CHECK_NRPE: Error - Could Not Complete SSL Handshake
I have also done

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iptables -F
on both VM and

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cd /tmp/nrpe-2.14
./configure --enable-ssl
make all
make install
2) With SSL Encryption disabled - I have the error of CHECK_NRPE: Error receiving data from daemon.

Someone please shed some light. :cry:

Re: CentOS - Unable to monitor Redhat OS

Posted: Wed Feb 11, 2015 2:42 am
by timlee
Also,

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[root@NagiosCentOS6 ~]# /usr/local/nagios/libexec/check_nrpe -H 192.168.168.123
CHECK_NRPE: Error - Could not complete SSL handshake.
192.168.168.123 is the client address. And from /var/log/messages

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Feb 11 02:59:52 localhost nrpe[26004]: Client request was invalid, bailing out..                                                                                        .
Feb 11 02:59:52 localhost xinetd[12974]: EXIT: nrpe status=0 pid=26004 duration=                                                                                        0(sec)
Feb 11 02:59:56 localhost xinetd[12974]: START: nrpe pid=26006 from=::ffff:192.1                                                                                        68.168.127
Feb 11 02:59:56 localhost xinetd[26006]: FAIL: nrpe address from=::ffff:192.168.                                                                                        168.127
Feb 11 02:59:56 localhost xinetd[12974]: EXIT: nrpe status=0 pid=26006 duration=                                                                                        0(sec)

Re: CentOS - Unable to monitor Redhat OS

Posted: Wed Feb 11, 2015 10:58 am
by scottwilkerson
You will need to edit /etc/xinetd.d/nrpe and add 192.168.168.127 to the only_from line
then

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service xinetd restart

Re: CentOS - Unable to monitor Redhat OS

Posted: Wed Feb 11, 2015 9:28 pm
by timlee
scottwilkerson wrote:You will need to edit /etc/xinetd.d/nrpe and add 192.168.168.127 to the only_from line
then

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service xinetd restart
Hi, after doing that, the status became unknown and the error CHECK_NRPE: Received 0 bytes from daemon. Check the remote server logs for error messages.

From /var/log/messages:

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Feb 11 21:25:29 localhost xinetd[9112]: EXIT: nrpe status=0 pid=10178 duration=0(sec)
Feb 11 21:25:48 localhost xinetd[9112]: START: nrpe pid=10231 from=::ffff:192.168.168.127
Feb 11 21:25:48 localhost nrpe[10231]: Error: Request contained command arguments!
Feb 11 21:25:48 localhost nrpe[10231]: Client request was invalid, bailing out...
Feb 11 21:25:48 localhost xinetd[9112]: EXIT: nrpe status=0 pid=10231 duration=0(sec)

Re: CentOS - Unable to monitor Redhat OS

Posted: Wed Feb 11, 2015 9:32 pm
by Box293
Edit /usr/local/nagios/etc/nrpe.cfg
Change:

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dont_blame_nrpe=0
To:

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dont_blame_nrpe=1

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service xinetd restart

Re: CentOS - Unable to monitor Redhat OS

Posted: Wed Feb 11, 2015 10:07 pm
by timlee
Box293 wrote:Edit /usr/local/nagios/etc/nrpe.cfg
Change:

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dont_blame_nrpe=0
To:

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dont_blame_nrpe=1

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service xinetd restart
Hi, I have done this as well on both the server and client. This log mentioned localhost nrpe[10231]: Error: Request contained command arguments!
What is the command I should edit as I am using the wizard.

Re: CentOS - Unable to monitor Redhat OS

Posted: Wed Feb 11, 2015 10:21 pm
by Box293
OK so that change is only required on the client.

Ignoring wizards and existing XI configurations for the moment, let's concentrate on running tests from the command line:

From your Nagios XI host run this command:

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/usr/local/nagios/libexec/check_nrpe -H 192.168.168.123
What does it output?

Re: CentOS - Unable to monitor Redhat OS

Posted: Wed Feb 11, 2015 10:31 pm
by timlee
Box293 wrote:OK so that change is only required on the client.

Ignoring wizards and existing XI configurations for the moment, let's concentrate on running tests from the command line:

From your Nagios XI host run this command:

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/usr/local/nagios/libexec/check_nrpe -H 192.168.168.123
What does it output?
Here is the output:

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[root@NagiosCentOS6 ~]# /usr/local/nagios/libexec/check_nrpe -H 192.168.168.123
NRPE v2.15

Re: CentOS - Unable to monitor Redhat OS

Posted: Wed Feb 11, 2015 10:40 pm
by Box293
Excellent, it's correctly listening.

So now lets look at what is configured in XI.

Configure - > Core Configuration Mananger
Monitoring -> Services
Find one of the services that is not currently working
Click the Disk icon for it
Paste the contents of the output from the disk icon here in a code block.

Also, from the remote host, please post:
/usr/local/nagios/etc/nrpe.cfg
Any files in:
/usr/local/nagios/etc/nrpe/

Re: CentOS - Unable to monitor Redhat OS

Posted: Wed Feb 11, 2015 10:55 pm
by timlee
Box293 wrote:Excellent, it's correctly listening.

So now lets look at what is configured in XI.

Configure - > Core Configuration Mananger
Monitoring -> Services
Find one of the services that is not currently working
Click the Disk icon for it
Paste the contents of the output from the disk icon here in a code block.

Also, from the remote host, please post:
/usr/local/nagios/etc/nrpe.cfg
Any files in:
/usr/local/nagios/etc/nrpe/
From config manager (Disk Usage):

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define service {
	host_name			192.168.168.123
	service_description		/ Disk Usage
	use				xiwizard_nrpe_service
	check_command			check_nrpe!check_disk!-a '-w 20% -c 10% -p /'
	max_check_attempts		5
	check_interval			5
	retry_interval			1
	check_period			xi_timeperiod_24x7
	notification_interval		60
	notification_period		xi_timeperiod_24x7
	contacts			nagiosadmin
	_xiwizard			linux-server
	register			1
	}	
From nrpe.cfg:

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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.
#
# 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=127.0.0.1 192.168.168.127



# 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=1



# 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=/usr/local/nagios/etc/nrpe



# 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 $ARG3$
/usr/local/nagios/etc/nrpe/common.cfg:

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### GENERIC SERVICES ###
command[check_init_service]=sudo /usr/local/nagios/libexec/check_init_service $ARG1$
command[check_services]=/usr/local/nagios/libexec/check_services -p $ARG1$

### MISC SYSTEM METRICS ###
#command[check_users]=/usr/local/nagios/libexec/check_users -w 5 -c 10
command[check_users]=/usr/local/nagios/libexec/check_users $ARG1$
command[check_load]=/usr/local/nagios/libexec/check_load $ARG1$
command[check_swap]=/usr/local/nagios/libexec/check_swap $ARG1$
command[check_cpu_stats]=/usr/local/nagios/libexec/check_cpu_stats.sh $ARG1$
command[check_mem]=/usr/local/nagios/libexec/custom_check_mem -n $ARG1$

### SYSTEM UPDATES ###
command[check_yum]=/usr/local/nagios/libexec/check_yum
command[check_apt]=/usr/local/nagios/libexec/check_apt

### DISK ###
command[check_disk]=/usr/local/nagios/libexec/check_disk $ARG1$
command[check_ide_smart]=/usr/local/nagios/libexec/check_ide_smart $ARG1$

### PROCESSES ###
command[check_all_procs]=/usr/local/nagios/libexec/custom_check_procs
command[check_procs]=/usr/local/nagios/libexec/check_procs $ARG1$

### OPEN FILES ###
command[check_open_files]=/usr/local/nagios/libexec/check_open_files.pl $ARG1$

### NETWORK CONNECTIONS ###
command[check_netstat]=/usr/local/nagios/libexec/check_netstat.pl -p $ARG1$ $ARG2$[root@localhost nrpe]# ^C
[root@localhost nrpe]# cat common.cfg

### GENERIC SERVICES ###
command[check_init_service]=sudo /usr/local/nagios/libexec/check_init_service $ARG1$
command[check_services]=/usr/local/nagios/libexec/check_services -p $ARG1$

### MISC SYSTEM METRICS ###
#command[check_users]=/usr/local/nagios/libexec/check_users -w 5 -c 10
command[check_users]=/usr/local/nagios/libexec/check_users $ARG1$
command[check_load]=/usr/local/nagios/libexec/check_load $ARG1$
command[check_swap]=/usr/local/nagios/libexec/check_swap $ARG1$
command[check_cpu_stats]=/usr/local/nagios/libexec/check_cpu_stats.sh $ARG1$
command[check_mem]=/usr/local/nagios/libexec/custom_check_mem -n $ARG1$

### SYSTEM UPDATES ###
command[check_yum]=/usr/local/nagios/libexec/check_yum
command[check_apt]=/usr/local/nagios/libexec/check_apt

### DISK ###
command[check_disk]=/usr/local/nagios/libexec/check_disk $ARG1$
command[check_ide_smart]=/usr/local/nagios/libexec/check_ide_smart $ARG1$

### PROCESSES ###
command[check_all_procs]=/usr/local/nagios/libexec/custom_check_procs
command[check_procs]=/usr/local/nagios/libexec/check_procs $ARG1$

### OPEN FILES ###
command[check_open_files]=/usr/local/nagios/libexec/check_open_files.pl $ARG1$

### NETWORK CONNECTIONS ###
/usr/local/nagios/etc/nrpe/asterisk.cfg

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### ASTERISK ###

command[check_asterisk]=/usr/local/nagios/libexec/check_asterisk.pl $ARG1$
command[check_sip]=/usr/local/nagios/libexec/check_sip $ARG1$
command[check_asterisk_sip_peers]=sudo /usr/local/nagios/libexec/check_asterisk_sip_peers.sh $ARG1$

# Nagisk (Asterisk) checks
command[check_asterisk_version]=/usr/local/nagios/libexec/nagisk.pl -c version
command[check_asterisk_peers]=/usr/local/nagios/libexec/nagisk.pl -c peers
command[check_asterisk_channels]=/usr/local/nagios/libexec/nagisk.pl -c channels
command[check_asterisk_zaptel]=/usr/local/nagios/libexec/nagisk.pl -c zaptel
command[check_asterisk_span]=/usr/local/nagios/libexec/nagisk.pl -c span -s 1