Installing Nagios

Installing Nagios3

Installing Nagios on Linux / Ubuntu is straight forward and simple...

Step: 1. apt-key update

Step: 2. apt-get update
Step  3. apt-get install y nagios3
* During the run you will asked to set domain, email and admin user

That's it....

#Start nagios
By script ->  /etc/init.d/nagios3 start
Manual -> nagios3 -d etc/nagios3/nagios.cfg

#reloading nagios
By Script -> /etc/init.d/nagios3 reload
Manual -> kill -HUP

#Stop nagios
By Script -> /etc/init.d/nagios3 stop
Manual -> kill

#To verify your configuration
nagios3 -v etc/nagios3/nagios.cfg

Nagios Configuration Files

Nagios Configuration Files
 Main Configuration File (Ref: http://nagios.sourceforge.net/docs/3_0/configmain.html)

•     Path: /etc/nagios3/nagios.cfg
•     The main configuration file contains a number of directives that affect how the Nagios daemon operates.
•     This config file is read by both the Nagios daemon and the CGIs.

 Resource File(s) (Ref: http://nagios.sourceforge.net/docs/3_0/configmain.html#resource_file)

•     Resource files can be used to store user-defined macros.
•     The main point of having resource files is to use them to store sensitive configuration information (like passwords), without making them available to the CGIs.     

 Object Definition Files (Ref: http://nagios.sourceforge.net/docs/3_0/configobject.html http://nagios.sourceforge.net/docs/3_0/objectdefinitions.html)

•     Object definition files are used to define hosts, services, hostgroups, contacts, contactgroups, commands, etc.
•     This is where you define all the things you want monitor and how you want to monitor them.
•     You can specify one or more object definition files by using the cfg_file and/or cfg_dir directives in your main configuration file.

  
 CGI Configuration File (Ref: http://nagios.sourceforge.net/docs/3_0/configcgi.html)

•     The CGI configuration file contains a number of directives that affect the operation of the CGIs.
•     It also contains a reference the main configuration file,
•         so the CGIs know how you've configured Nagios and where your object definitions are stored.

CMDB - Configuration Management Database - snapshot

What is CMDB

CMDB is a Configuration Management Database. CMDB is repository of CI (Configurable Items) with it properties and relations.

CMDB and NoSQL
CI's properties and its relations are not static and will change time by time. So, NoSQL is the best store for CMDB as it is very dynamic and doesn't required any schema. The schema can be altered at run time.

CMDB and Graph
In nature Graph theory consists of nodes, properties and edges. This perfectly fits for CMDB (Nodes - CI, Properties - Properties of CI and the edges - Relations of nodes). Graph database are powerful for graph-like queries.

Graph database is more flexible, faster, less depedent on rigid schema than the RDBMS database.

Architect & Architecture

Architectecture

Practices used to design the applications. The practices involves

• Analyzing the business requirements
• Communicating the stakeholders
• Designing the high level system model
• Selecting the infrastructure and technology
• Preparing the High Level Design document
• Choosing and Designing Frameworks and Patterns
• Selecting the process model & standards
• Desinging the deployment strategy
• Educating the team
• Coding the system
• Reviewing the application & Deployments

Takeaway

• System Design
• Reusable Components
• Lessons Learned
• New Technology & Standard adoption
• Domain Knowledge
• Best Practices