Use this guide to install the latest version of Check_MK and Nagios.

Prerequisites

• EPEL repository
• Disable SELinux. Normally i would let SELinux be enabled, but with a monitoring system it is one of the few exceptions I make. This service does too many things SELinux doesn't like.

• Install rrdtool:

  yum install rrdtool perl-rrdtool

• Install development tools:

  yum groupinstall development tools

• Install apache & php.

  yum install httpd php

• Install other requirements.

  yum install gd gd-devel php-gd openssl-devel net-snmp net-snmp-utils policycoreutils-python dejavu-fonts-common dejavu-sans-mono-fonts dejavu-lgc-sans-mono-fonts

• Create user and group.

  useradd nagios
  groupadd nagcmd
  usermod -a -G nagcmd nagios
  usermod -G nagcmd apache

• Download latest version.
• Extract.

  tar zxvf nagios-4.0.8.tar.gz

• Compile Nagios 4.

  cd nagios-4.0.8
  ./configure --with-command-group=nagcmd --prefix=/opt/nagios --exec-prefix=/opt/nagios
  make all
  make install
  make install-init
  make install-config
  make install-commandmode
  make install-webconf
  cp -R contrib/eventhandlers/ /opt/nagios/libexec/
  chown -R nagios:nagios /opt/nagios/libexec/eventhandlers

• Test and start Nagios, it still uses legacy init:

  /opt/nagios/bin/nagios -v /opt/nagios/etc/nagios.cfg
  service nagios start

• Edit /opt/nagios/etc/resource.cfg

  $USER1$=/opt/nagios-plugins/libexec

• Add a default user for Web Interface Access

  htpasswd -c /opt/nagios/etc/htpasswd.users nagiosadmin

• Download latest Nagios plugins.
• Install Nagios Plugins:

  cd
  tar zxvf nagios-plugins-2.0.3.tar.gz
  cd /tmp/nagios-plugins-2.0.3
  ./configure --with-nagios-user=nagios --with-nagios-group=nagios --prefix=/opt/nagios-plugins --exec-prefix=/opt/nagios-plugins
  make
  make install

• Service setup.

  chkconfig --add nagios
  chkconfig --level 35 nagios on
  systemctl enable httpd

• Open port 80 / 443:

  firewall-cmd --permanent --zone public --add-service=http
  firewall-cmd --permanent --zone public --add-service=https
  firewall-cmd --reload

• Give the Nagios localhost http check something.

  touch /var/www/html/index.html

• Start Apache, restart Nagios, it should be running on your webserver /nagios

  service nagios restart
  systemctl start httpd

• Download the latest PNP4nagios.
• Extract.

  tar zxvf pnp4nagios.tgz

• Compile.

  cd pnp4nagios-0.6.25
  ./configure --prefix=/opt/pnp4nagios --exec-prefix=/opt/pnp4nagios
  make all
  make fullinstall

• Configure apache, edit /etc/httpd/conf.d/pnp4nagios.conf

  AuthUserFile /opt/nagios/etc/htpasswd.users

• Restart apache.

  systemctl restart httpd

• Configure Nagios to use PNP4nagios. Edit /opt/nagios/etc/nagios.cfg.

  #
  # Bulk / NPCD mode
  #
  
  process_performance_data=1
  
  # *** the template definition differs from the one in the original nagios.cfg
  #
  service_perfdata_file=/opt/pnp4nagios/var/service-perfdata
  service_perfdata_file_template=DATATYPE::SERVICEPERFDATA\tTIMET::$TIMET$\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=/opt/pnp4nagios/var/host-perfdata
  host_perfdata_file_template=DATATYPE::HOSTPERFDATA\tTIMET::$TIMET$\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

• Edit /opt/nagios/etc/objects/commands.cfg Disable sample performance data commands, add:

  #
  # Bulk mode
  #
  define command {
         command_name    process-service-perfdata-file
         command_line    /opt/pnp4nagios/libexec/process_perfdata.pl --bulk /opt/pnp4nagios/var/service-perfdata
  }
  define command {
         command_name    process-host-perfdata-file
         command_line    /opt/pnp4nagios/libexec/process_perfdata.pl --bulk /opt/pnp4nagios/var/host-perfdata
  }

• Remove install file.

  rm /opt/pnp4nagios/share/install.php

• Restart nagios.

  service nagios restart

• Open /pnp4nagios on your webserver, it might take a while before data has been processed and images are shown.

• Install xinetd.

  yum install xinetd
  service xinetd start
  chkconfig xinetd on

• Download latest Check_MK version.
• Extract.

  tar zxvf check_mk-1.2.6p1.tar.gz

• Compile.

  cd check_mk-1.2.6p1
  ./setup.sh
  
  You have chosen the following directories:
  
   Executable programs             /opt/check_mk/bin
   Check_MK configuration          /opt/check_mk/etc
   Check_MK software               /opt/check_mk/share
   documentation                   /opt/check_mk/share/doc
   check manuals                   /opt/check_mk/share/doc/check_mk/checks
   working directory of Check_MK   /opt/check_mk/var/lib
   extensions for agents           /usr/lib/check_mk_agent
   configuration dir for agents    /etc/check_mk
   Name of Nagios user             nagios
   User of Apache process          apache
   Common group of Nagios+Apache   nagcmd
   Nagios binary                   /opt/nagios/bin/nagios
   Nagios main configuration file  /opt/nagios/etc/nagios.cfg
   Nagios object directory         /opt/nagios/etc/check_mk.d
   Nagios startskript              /etc/init.d/nagios
   Nagios command pipe             /opt/nagios/var/rw/nagios.cmd
   Check results directory         /opt/nagios/var/spool/checkresults
   Nagios status file              /opt/nagios/var/status.dat
   Path to check_icmp              /opt/nagios-plugins/libexec/check_icmp
   URL Prefix for Web addons       /
   Apache config dir               /etc/httpd/conf.modules.d
   HTTP authentication file        /opt/nagios/etc/htpasswd.users
   HTTP AuthName                   Nagios Access
   PNP4Nagios templates            /opt/pnp4nagios/share/templates
   RRD files                       /opt/pnp4nagios/var/perfdata
   rrdcached socket                /tmp/rrdcached.sock
   compile livestatus module       yes
   Nagios / Icinga version         4.0.8
   check_mk's binary modules       /opt/check_mk/lib
   Unix socket for Livestatus      /opt/nagios/var/rw/live
   Backends for other systems      /opt/check_mk/share/livestatus
   Install Event Console           yes
   working directory of mkeventd   /opt/mkeventd/lib
  
    Proceed with installation (y/n)? y
  (Compiling MK Livestatus....................................................)
  Installation completed successfully.
  Please restart Nagios and Apache in order to update/active check_mk's web pages.
  
  You can access the new Multisite GUI at http://localhost/check_mk/
                         

The current version (1.2.6x) of Check_MK still needs the old mod_python.

• Install development tools:

  yum install python-devel httpd-devel

• Download latest modpython source code.
• Extract:

  tar zxvf mod_python-3.5.0.tgz

• Install:

  cd mod_python-3.5.0
  ./configure
  make
  make install
  
  # Edit /usr/lib64/python2.7/site-packages/mod_python/version.py
  # Change version line to: version = "3.5.0"
  vi /usr/lib64/python2.7/site-packages/mod_python/version.py

• Configure and Apache:

  # in /etc/httpd/conf.modules.d, create 00-python.conf with the following LoadModule line inside it
  LoadModule python_module modules/mod_python.so
  
  systemctl restart httpd

• Enable and Start mkeventd:

  chkconfig --add mkeventd
  chkconfig --level 35 mkeventd on
  service mkeventd start

• Install Check_MK client on host.

  yum install xinetd
  
  cd check_mk-1.2.6p1
  mkdir agents
  cd agents
  tar zxvf ../agents.tar.gz
  
  mkdir /opt/check_mk_agent
  cp check_mk_agent.linux /opt/check_mk_agent/bin/check_mk_agent
  
  cp xinetd.conf /etc/xinetd.d/check_mk_agent
  # Edit path and allowed hosts
  #        server         = /opt/check_mk_agent/bin/check_mk_agent
  #        only_from      = 127.0.0.1
  vi /etc/xinetd.d/check_mk_agent
  
  systemctl enable xinetd
  systemctl start xinetd
  
  
  
  # Test agent
  nc 127.0.0.1 6556
  

• Configure monitoring host in Check_MK itself, add host, IP-address 127.0.0.1.
• Remove localhost from /opt/nagios/etc/nagios.cfg, then restart all of Check_MK:

  /opt/check_mk/bin/cmk -R.

• Modify rights:

  chown -R apache.nagcmd /opt/check_mk/etc
  chown -R nagios.nagcmd /opt/check_mk/var/lib/
  chown -R apache.nagcmd /opt/check_mk/var/lib/wato
  chgrp -R nagcmd /opt/nagios/etc/
  chown -R apache.nagcmd /opt/check_mk/var/lib/wato
  
  chmod g+w /opt/check_mk/etc
  chmod g+w /opt/check_mk/var/lib/
  chmod g+w /opt/nagios/etc/

• Nagios warns about obsoleted feature, remove failure_prediction_enabled from template file /opt/nagios/etc/check_mk.d/check_mk_templates.cfg

• Edit /opt/nagios/etc/nagios.cfg

  use_syslog=0

• Restart nagios.

  service nagios restart

Note: the EPEL version is older and might have some incompatibilities, you can also install the RPM provided with the Check_MK tar.gz

• Install check_mk agent via EPEL:

  yum -y install check-mk-agent
  vi /etc/xinetd.d/check-mk-agent # change only_from
  
  firewall-cmd --permanent --zone trusted --add-service=checkmkagent
  firewall-cmd --reload
  
  systemctl enable xinetd
  systemctl restart xinetd

• Download latest tar.gz
• Extract
• Run ./setup.sh
• Restart nagios and apache
• Fix notifications (see above), after run cmk -O (captital o)