NAGIOS MONITORING SERVER (Installation & Configurations)

NAGIOS INSTALLATION  & CONFIGURATION

ü  Login as root .

ü  Download  nagios core package & nagios plugins to the Desktop from http://www.nagios.org/download.

ü  Move the nagios core package from desktop to a directory /usr/local/nagios.  If it is not there then create it ………                                                                                                   #mkdir /usr/local/nagios

ü  #mv nagios…tar.gz /usr/local/nagios

ü  # cd /usr/local/nagios

ü  # tar xzvf nagios….tar.gz

ü  # ls

ADDING USERS & GROUPS

ü  # adduser nagios

ü  # groupadd nagcmd

Adding nagios and Apache users to nagcmd:

ü  # usermod –G nagcmd nagios

ü  # usermod –G nagcmd Apache

[ Apache user will be automatically created if httpd package is installed. ]

ü  Changing user and group owner for /usr/local/nagios-

    # chown nagios.nagios /usr/local/nagios

ü  Then ...

   

    #  cd  /usr/local/nagios

    #  ls

   

 As we have already extracted nagios core package that was in tar.gz form , we will see one folder for nagios.

 

   # cd nagios-3.0.3

   # ./configure –prefix=/usr/local/nagios

                         --with-cgiurl=/nagios/cgi-bin  --with-htmurl=/nagios/

--with-nagios-user=nagios  --with-nagios-group=nagios

--with-command-group=nagcmd

Compiling binaries-

# make all             
[compiles nagios and CGIs. (compiles—error checking for the source code)]

Installing binraies                                           

# make install                                     
[Installing binaries and HTML files i.e the documentation and the main webpage

# make install-init                                Installing init script to /etc/rc.d/init.d/nagios

# make install-commandmode

# make install-config                            
[To get configuration files like main,resource and CGI configuration files installed.]

HOW TO CHECK NAGIOS IS INSTALLED OR NOT ?

# cd /usr/local/nagios

# ls

We should get five directories as

 etc  ------ Contains  Main, resource,CGI configuration files

 bin  ------ Contains Nagios core program

 share ----  Contains HTML files for web interface and online documentation.

 Sbin -----  Contains CGIs

 Var ------  Contains logfiles, status files etc.

 Libexec –

NAGIOS PLUG-INS:

Nagios plug-ins are installed in libexec directory.

Here we moved the nagos plug-in package from Desktop to /usr/local/nagios/libexec.  But it is not compulsory  to extract the package in side the libexec directory.  Where ever we extract, it will be installed in libexec.

# mv nagios-plugins…tar.gz  /usr/local/nagios/libexec

# cd /usr/local/nagios/libexec

# tar xxvf nagios-plugin-…tar.gz

# ls

# cd nagios-plugins-1.4.13

# ./configure –prefix=/usr/local/nagios  --with-nagios-user=nagios

        –with-nagios-group=nagios

It may show some RedHat soaping or some problem related to RedHat.

Then try---

# ./configure –enable-redhat-pthread-workaround    [preferable]

Or

# ./configure –disable-redhat-pthread

Then   

# make all

# make install

Nagios plug-ins are installed.

3) Post install Configuration of Nagios

Edit apache’s httpd.conf file. (the location of the httpd.conf file may differ)

vim /etc/httpd/conf/httpd.conf

Add the following line at the end of the file.

Include /etc/httpd/conf/nagios.conf

Create the file ‘/etc/httpd/conf/nagios.conf’.

vi /etc/httpd/conf/nagios.conf

Add the following contents to this file.
————————————————-
ScriptAlias /nagios/cgi-bin/ /usr/local/nagios/sbin/
<Directory /usr/local/nagios/sbin/>
AllowOverride AuthConfig
Options ExecCGI
Allow from all
Order allow,deny
</Directory>

Alias /nagios/ /usr/local/nagios/share/
<Directory /usr/local/nagios/share/>
Options None
AllowOverride AuthConfig
Order allow,deny
Allow from all
</Directory>
————————————————–

Make sure the updations done with http is fine and restart apache.

#service httpd restart

Create ‘.htaccess’ file in ‘/usr/local/nagios/share/’ and ‘/usr/local/nagios/sbin/’.

#touch /usr/local/nagios/share/.htaccess

#touch /usr/local/nagios/sbin/.htaccess   - securing access to CGI files.

Add the following contents to both these files.

AuthName "Nagios Access"

AuthType Basic

AuthUserFile /usr/local/nagios/etc/htpasswd.users

require valid-user

Create the username, password for logging into the Nagios interface.

htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin

ls -l /usr/local/nagios/etc/htpasswd.users

Make it available for the user who runs httpd.

chmod o+r /usr/local/nagios/etc/htpasswd.users

Restart the httpd service.

service httpd restart

5)Advanced Nagios Configurations.

Rename the sample files to the real names.

cd /usr/local/nagios/etc/

for i in *sample ; do mv $i `echo "$i" |sed s/-sample//` ; done

Edit the main conf file, nagios.cfg. and change only these lines.

check_external_commands=1

Make these Cgi specific changes in cgi.cfg.
Physical_html_path=/usr/local/nagios/share

use_authentication=1

authorized_for_system_information=nagiosadmin

authorized_for_configuration_information=nagiosadmin

authorized_for_system_commands=nagiosadmin

authorized_for_all_services=nagiosadmin

authorized_for_all_hosts=nagiosadmin

authorized_for_all_service_commands=nagiosadmin

authorized_for_all_host_commands=nagiosadmin

# service httpd restart      [Try http://localhost/nagios  now]

If  the authentication for the cgi files in side /usr/local/nagios/sbin directory are not enabled, then we won’t be able to r

submit passive checks for a particular service for a particular host in nagios manually.