Configuring Nagios (Part II)

Nagvis is an Addon for nagios that allow create our own maps with the nagios information services. The classical method to collect services data from Nagios is reading the file status.dat, this file is updated every 10 seconds by default defined on the entry status_update_interval in nagios.cfg. Mk livestatus is a module loaded with Nagios that send all status update over UNIX socket and create SQL sentences. Mk livestatus it’s very popular in the developer of addons, is very easy to read data from this process and the information is actually not updated every 10. Nagvis uses live status for read information about hosts and services.

- Installing mk livestatus:

1.- Install dependencies:

# yum install make gcc-c++ wget

2.- Download mk livestatus:

# cd /tmp && wget http://mathias-kettner.de/download/mk-livestatus-1.1.12p7.tar.gz

3.- Extract package:

# tar -xzvf mk-livestatus-1.1.12p7.tar.gz

4.- Install:

# cd mk-livestatus-1.1.12p7/ && ./configure
# make && make install

5.- Create new directory with correct permissions:

# mkdir /usr/lib/nagios/mk-livestatus && chown nagios:apache /usr/lib/nagios/mk-livestatus

6.- Edit /etc/nagios/nagios.cfg :

broker_module=/usr/local/lib/mk-livestatus/livestatus.o /usr/lib/nagios/mk-livestatus/live

7.- Restart Nagios:

# service nagios restart

8.- Try command line:

# echo 'GET hosts' | unixcat /usr/lib/nagios/mk-livestatus/live

For more information of query syntax:

http://mathias-kettner.de/checkmk_livestatus.html

Configuring Nagvis

1.- Install dependencies:

# yum install php-mbstring php-gd php-pdo graphviz rsync

2.- Download Nagvis:

# cd /tmp && wget http://sourceforge.net/projects/nagvis/files/NagVis%201.6/nagvis-1.6.4.tar.gz/download

3.- Extract package:

# tar -xzvf nagvis-1.6.4.tar.gz

4.- Installing Nagvis:

cd nagvis-1.6.4/ && ./install.sh
+--- Checking paths -----------------------------------------------------------+
| Please enter the path to the nagios base directory [/usr/sbin/nagios]: /etc/nagios
| Please enter the path to NagVis base [/usr/sbin/nagvis]: /usr/share/nagvis
| Do you want to use backend mklivestatus? [y]:y
| Livestatus Socket (/etc/nagios/var/rw/live) MISSING |
| Valid socket formats are: tcp:127.0.0.1:7668 or unix:/path/to/live |
| Please enter your MKLivestatus socket: unix:/usr/lib/nagios/mk-livestatus/live

5.-Edit /usr/sbin/nagvis/etc/nagvis.ini.php:

[defaults]
; default backend (id of the default backend)
backend="live_1"
[backend_live_1]
backendtype="mklivestatus"
socket="unix:/usr/lib/nagios/mk-livestatus/live"

6.- Reload apache:

# service httpd reload

7.- Access http://192.168.1.68/nagvis :
Default user and password admin // admin

Configuring PNP4Nagios

pnp4nagios is an addon for Nagios that can build graphs based in rrdtool like cacti of hosts and services checks that produce Nagios. We can configure pnpp4nagios in some modes, here i’ll explain how to configure with bulk mode, basically this mode reduce the use of cpu because the process is not called for every service/host check. For more information see:
http://docs.pnp4nagios.org/pnp-0.6/config

1.- Installing pnp4nagios:

# yum install pnp4nagios

2.- Edit /etc/nagios/nagios.cfg:

process_performance_data=1
# *** the template definition differs from the one in the original nagios.cfg
service_perfdata_file=/var/log/pnp4nagios/service-perfdata
service_perfdata_file_template=DATATYPE::
SERVICEPERFDATAtTIMET::$TIMET$tHOSTNAME::
$HOSTNAME$tSERVICEDESC::
$SERVICEDESC$tSERVICEPERFDATA::
$SERVICEPERFDATA$tSERVICECHECKCOMMAND::
$SERVICECHECKCOMMAND$tHOSTSTATE::
$HOSTSTATE$tHOSTSTATETYPE::
$HOSTSTATETYPE$tSERVICESTATE::
$SERVICESTATE$tSERVICESTATETYPE::
$SERVICESTATETYPE$
service_perfdata_file_mode=a
service_perfdata_file_processing_interval=15
service_perfdata_file_processing_command=process-service-perfdata-file
# *** the template definition differs from the one in the original nagios.cfg
#
host_perfdata_file=/var/log/pnp4nagios/host-perfdata
host_perfdata_file_template=DATATYPE::HOSTPERFDATAtTIMET::
$TIMET$tHOSTNAME::$HOSTNAME$tHOSTPERFDATA::
$HOSTPERFDATA$tHOSTCHECKCOMMAND::
$HOSTCHECKCOMMAND$tHOSTSTATE::
$HOSTSTATE$tHOSTSTATETYPE::$HOSTSTATETYPE$
host_perfdata_file_mode=a
host_perfdata_file_processing_interval=15
host_perfdata_file_processing_command=process-host-perfdata-file

3.- Edit /etc/nagios/objects/commands.cfg:

define command{
command_name process-service-perfdata-file
command_line /usr/libexec/pnp4nagios/process_perfdata.pl --bulk=/var/log/pnp4nagios/service-perfdata
}
define command{
command_name process-host-perfdata-file
command_line /usr/libexec/pnp4nagios/process_perfdata.pl --bulk=/var/log/pnp4nagios/host-perfdata
}

4.- Restart Nagios

# service nagios restart

5.- Verify configuration:

# cd /tmp ; wget http://verify.pnp4nagios.org/verify_pnp_config && perl verify_pnp_config --mode bulk --config=/etc/nagios/nagios.cfg --pnpcfg=/etc/pnp4nagios

PNP4Nagios popups for Nagios

1.- Copy the status-header javascript of pnp4nagios to nagios:

# cp /usr/share/doc/pnp4nagios-0.6.16/contrib/ssi/status-header.ssi /usr/share/nagios/html/ssi/

2.- Add a new template to use and apply to hosts and services to show graph popup defined in the entry action_url:

# vi /etc/nagios/objects/templates.cfg

define host{
name host-pnp
action_url /pnp4nagios/graph?host=$HOSTNAME$&srv=_HOST_' class='tips' rel='/pnp4nagios/popup?host=$HOSTNAME$&srv=_HOST_
}

define service{
name service-pnp
action_url /pnp4nagios/graph?host=$HOSTNAME$&srv=$SERVICEDESC$' class='tips' rel='/pnp4nagios/popup?host=$HOSTNAME$&srv=$SERVICEDESC$
}

3.- Restart Nagios

# service nagios restart

Adding new services to graph for PNP4Nagios

Now I’ll add a script that will generate the number of SQL queries of a MySQL server and PNP4Nagios will graph the queries statistics.

1.- Installing dependencies:

# yum install perl-Class-DBI-mysql

2.- Download Scripts:
http://exchange.nagios.org/components/com_mtree/attachment.php?link_id=174&cf_id=30
http://exchange.nagios.org/components/com_mtree/attachment.php?link_id=174&cf_id=36

3.- Adding new command and internal variable to nagios:

#vi /etc/nagios/objects/commands.cfg

define command{
command_name check_mysqld
command_line $USER1$/check_mysqld.pl -H $HOSTADDRESS$ -u nagios -p $USER7$ -a uptime,threads_connected,questions,slow_queries,open_tables -w ',,,,' -c ',,,,' -A $USER21$
}

- Edit /etc/nagios/private/resource.cfg and add:

$USER7$=nagios
$USER21$='com_select,com_update,com_insert,com_insert_select,
com_commit,com_delete,com_rollback,aborted_clients,
aborted_connects,binlog_cache_disk_use,binlog_cache_use,
bytes_received,bytes_sent,connections,created_tmp_disk_tables,
created_tmp_files,created_tmp_tables,delayed_errors,
delayed_insert_threads,delayed_writes,handler_update,handler_write,
handler_delete,handler_read_first,handler_read_key,
handler_read_next,handler_read_prev,handler_read_rnd,
handler_read_rnd_next,key_blocks_not_flushed,
key_blocks_unused,key_blocks_used,key_read_requests,key_reads,
key_write_requests,key_writes,max_used_connections,
not_flushed_delayed_rows,open_files,open_streams,open_tables,
opened_tables,prepared_stmt_count,qcache_free_blocks,
qcache_free_memory,qcache_hits,qcache_inserts,
qcache_lowmem_prunes,qcache_not_cached,
qcache_queries_in_cache,qcache_total_blocks,questions,
select_full_join,select_rangle_check,slow_launch_threads,
slow_queries,table_locks_immediate,table_locks_waited,
threads_cached,threads_connected,threads_created,
threads_running'

4.- Edit /etc/nagios/objects/localhost.cfg

define service {
use local-service,service-pnp
hostgroup_name nagios-pool
service_description MYSQLD
check_command check_mysqld!nagios!nagios
}

5.- Copy script file and php template for pnp4nagios:

- create file /etc/pnp4nagios/check_commands/check_mysqld.cfg and add:

# vi /etc/pnp4nagios/check_commands/check_mysqld.cfg

# Adjust the whole RRD Database
DATATYPE = COUNTER 

- copy the script in perl in the default plugin directory for nagios (/usr/lib/nagios/plugins):

/usr/lib/nagios/plugins/check_mysqld.pl

 # chmod 755 /usr/lib/nagios/plugins/check_mysqld.pl
# chgrp nagios /usr/lib/nagios/plugins/check_mysqld.pl

- Copy the php script for generate data for rrdtool graphs:

/usr/share/nagios/html/pnp4nagios/templates.dist/check_mysqld.php

For more information to create custom templates for pnp4nagios, see:

http://docs.pnp4nagios.org/pnp-0.6/tpl_custom