NRPE client configuration on HP-UX 11v3

[fao]

Hi,

we are trying to configure the nrpe client on an Itanium installed with HP-UX 11v3.

We are using the package that comes with the installation of iexpress.

This is how it is configured:

- in /etc/services we added the following line
nrpe 5666/tcp #NAGIOS

- this is the netstat
# netstat -an | grep 5666
tcp 0 0 *.5666 *.* LISTEN

- in /etc/inetd.conf we added the following line
nrpe stream tcp nowait nagios /opt/iexpress/nagios/bin/nrpe -n -c /opt/iexpress/nagios/etc/nrpe.cfg -i (we disabled for the moment the SSL support to have a "simpler" debug)

In attachment the nrpe.conf.

- The permissions on the directory tree are the following
/opt ---> dr-xr-xr-x 98 bin bin
/opt/iexpress ---> dr-xr-xr-x 26 bin bin
/opt/iexpress/nagios (and subfolders) ---> dr-xr-xr-x 12 nagios nagios

- Making checks:
as user nagios:
$ /opt/iexpress/nagios/libexec/check_nrpe -H localhost
NRPE v2.12

$ /opt/iexpress/nagios/libexec/check_users -w 5 -c 10
USERS WARNING - 9 users currently logged in |users=9;5;10;0

$ /opt/iexpress/nagios/libexec/check_nrpe -H localhost -n -c check_users
CHECK_NRPE: Received 0 bytes from daemon. Check the remote server logs for error messages.

- syslog entry
Nov 22 15:16:49 udvdbs05 nrpe[24061]: INFO: SSL/TLS initialized. All network traffic will be encrypted.
Nov 22 15:16:49 udvdbs05 nrpe[24061]: Error: Could not complete SSL handshake. 1

$ /opt/iexpress/nagios/libexec/check_nrpe -H localhost -c check_users
NRPE: Unable to read output

- syslog entry
Nov 22 15:18:16 udvdbs05 nrpe[24221]: INFO: SSL/TLS initialized. All network traffic will be encrypted.
Nov 22 15:18:29 udvdbs05 nrpe[24242]: INFO: SSL/TLS initialized. All network traffic will be encrypted.
Nov 22 15:18:29 udvdbs05 nrpe[24242]: Error: Request contained command arguments!
Nov 22 15:18:29 udvdbs05 nrpe[24242]: Client request was invalid, bailing out...

The nagios server is on a Linux VM and, obviously, isn't able to monitor this machine.

Could you kindly support?

Thanks

[mguthrie]

Nov 22 15:18:29 udvdbs05 nrpe[24242]: Error: Request contained command arguments!

In order for NRPE to accept arguments, you'll need to edit the setting:

Code: Select all

dont_blame_nrpe=1

in the nrpe.cfg file. Then restart the daemon.

[fao]

yes,

it was done, but it didn't work

[lmiltchev]

I am not sure about inetd, but if you were using xinetd, in "/etc/xinetd.d/nrpe" there is a line: "only_from = ", where you enter you local host IP but more importantly, your Nagios server IP address. This is one thing to check.
Also, try using ssl. Remove the "-n" argument.

Restart the daemon and run:

Code: Select all

# tail /var/log/messages

See if you have anything NRPE-related.

Try running from your Nagios XI box:

Code: Select all

# cd /usr/local/nagios/libexec
# ./check_nrpe -H <target_machine_IP>

You should get: NRPE v2.12

[mguthrie]

Is "check_users" defined as an eligible command in the nrpe config? It would look something like:

Code: Select all

command[check_users]=/usr/local/nagios/libexec/check_users -w 5 -c 10

[fao]

OK,

maybe the nrpe.conf was not attached correctly so I will put it here

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/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=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=1



# 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]=/opt/iexpress/nagios/libexec/check_users -w 5 -c 10
command[check_load]=/opt/iexpress/nagios/libexec/check_load -w 15,10,5 -c 30,25,20
command[check_hpux_disk]=/opt/iexpress/nagios/libexec/check_disk -w 20 -c 10
command[check_zombie_procs]=/opt/iexpress/nagios/libexec/check_procs -w 5 -c 10 -s Z
command[check_total_procs]=/opt/iexpress/nagios/libexec/check_procs -w 150 -c 200 
command[check_swap]=/opt/iexpress/nagios/libexec/check_swap -w 20 -c 10
command[check_ping]=/opt/iexpress/nagios/libexec/check_ping -H 127.0.0.1 -w 100.0,20% -c 500.0,60%

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

To mguthrie:

basically I am calling the static command "check_users" that is defined into the nrpe.conf.

To Imiltchev:

On HPUX you must work on /etc/services and /etc/inetd.conf, there isn't xinetd, and the directive "only_from" can't be added.
removed the -n and restarted the inetd

- syslog entry
Nov 23 13:12:23 udvdbs05 inetd[1755]: nrpe/tcp: New arguments for server /opt/iexpress/nagios/bin/nrpe
Nov 23 13:12:23 udvdbs05 inetd[1755]: Configuration complete


rerun the checks in the two ways (with check_nrpe and without)
$ /opt/iexpress/nagios/libexec/check_nrpe -H localhost -c check_users
CHECK_NRPE: Error - Could not complete SSL handshake.

- syslog entry
Nov 23 13:18:18 udvdbs05 nrpe[2840]: Unable to open config file '//nrpe.cfg' for reading
Nov 23 13:18:18 udvdbs05 nrpe[2840]: Config file '//nrpe.cfg' contained errors, aborting...


$ /opt/iexpress/nagios/libexec/check_users -w 5 -c 10
USERS OK - 5 users currently logged in |users=5;5;10;0

- syslog entry
no entries

[mguthrie]

This is one question I might have to defer to the nagios users mailing list on source forge, or the nagios IRC channel on freenode. We don't have NRPE installation on HPUX documented, and we don't have a system to test on. My guess would be that this is an SSL issue, but it's hard to say for sure. It seems like it's really close to working, but from here we're somewhat firing in the dark as far as HPUX goes.

[fao]

Now what I am wondering about is: if it is an issue of SSL, why it doesn't work with the SSL disabled?

[mguthrie]

Is there any chance there could be a firewall rule in place that's causing the issue?