Monday, December 19, 2011

Nagios server configuration

Prerequisites
During portions of the installation you'll need to have root access to your machine.
Make sure you've installed the following packages on your Fedora installation before continuing.
  • Apache
  • PHP
  • GCC compiler
  • GD development libraries
You can use yum to install these packages by running the following commands (as root):
yum install httpd php  yum install gcc glibc glibc-common  yum install gd gd-devel
1) Create Account Information
Become the root user.
su -l
Create a new nagios user account and give it a password.
/usr/sbin/useradd -m nagios passwd nagios
Create a new nagcmd group for allowing external commands to be submitted through the web interface. Add both the nagios user and the apache user to the group.
/usr/sbin/groupadd nagcmd /usr/sbin/usermod -a -G nagcmd nagios /usr/sbin/usermod -a -G nagcmd apache

2) Download Nagios and the Plugins
Create a directory for storing the downloads.
mkdir ~/downloads  cd ~/downloads  
Download the source code tarballs of both Nagios and the Nagios plugins (visit http://www.nagios.org/download/ for links to the latest versions). These directions were tested with Nagios 3.1.1 and Nagios Plugins 1.4.11.
wget http://prdownloads.sourceforge.net/sourceforge/nagios/nagios-3.2.3.tar.gz
wget http://prdownloads.sourceforge.net/sourceforge/nagiosplug/nagios-plugins-1.4.11.tar.gz  
3) Compile and Install Nagios
Extract the Nagios source code tarball.
cd ~/downloads  tar xzf nagios-3.2.3.tar.gz  cd nagios-3.2.3  
Run the Nagios configure script, passing the name of the group you created earlier like so:
./configure --with-command-group=nagcmd  
Compile the Nagios source code.
make all  
Install binaries, init script, sample config files and set permissions on the external command directory.
make install 
make install-init 
make install-config 
make install-commandmode  
Don't start Nagios yet - there's still more that needs to be done...
4) Customize Configuration
Sample configuration files have now been installed in the /usr/local/nagios/etc directory. These sample files should work fine for getting started with Nagios. You'll need to make just one change before you proceed...
Edit the /usr/local/nagios/etc/objects/contacts.cfg config file with your favorite editor and change the email address associated with the nagiosadmin contact definition to the address you'd like to use for receiving alerts.
vi /usr/local/nagios/etc/objects/contacts.cfg
5) Configure the Web Interface
Install the Nagios web config file in the Apache conf.d directory.
make install-webconf
Create a nagiosadmin account for logging into the Nagios web interface. Remember the password you assign to this account - you'll need it later.
htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin
Restart Apache to make the new settings take effect.
service httpd restart

6) Compile and Install the Nagios Plugins
Extract the Nagios plugins source code tarball.
cd ~/downloads 
tar xzf nagios-plugins-1.4.11.tar.gz 
cd nagios-plugins-1.4.11  
Compile and install the plugins.
./configure --with-nagios-user=nagios --with-nagios-group=nagios 
make 
make install

7) Start Nagios  
Add Nagios to the list of system services and have it automatically start when the system boots.
chkconfig --add nagios chkconfig nagios on
Verify the sample Nagios configuration files.
/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
If there are no errors, start Nagios.
service nagios start

8) Modify SELinux Settings
Fedora ships with SELinux (Security Enhanced Linux) installed and in Enforcing mode by default. This can result in "Internal Server Error" messages when you attempt to access the Nagios CGIs.
See if SELinux is in Enforcing mode.
getenforce  
Put SELinux into Permissive mode.
setenforce 0  
To make this change permanent, you'll have to modify the settings in /etc/selinux/config and reboot.
Instead of disabling SELinux or setting it to permissive mode, you can use the following command to run the CGIs under SELinux enforcing/targeted mode:
chcon -R -t httpd_sys_content_t /usr/local/nagios/sbin/ 
chcon -R -t httpd_sys_content_t /usr/local/nagios/share/

9) Login to the Web Interface  
You should now be able to access the Nagios web interface at the URL below. You'll be prompted for the username (nagiosadmin) and password you specified earlier.
http://localhost/nagios/





No comments:

Post a Comment