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Basics About Nagios


  1. 1. NAGIOS A System and Network Monitoring Application
  2. 2. Agenda <ul><li>Introduction </li></ul><ul><ul><ul><ul><li>Objectives </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Features </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Requirements </li></ul></ul></ul></ul><ul><li>Architecture and Operation </li></ul><ul><ul><ul><ul><li>Operation Description </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Web Portal </li></ul></ul></ul></ul><ul><li>Plug-ins </li></ul><ul><ul><ul><ul><li>Plug-ins Description </li></ul></ul></ul></ul>
  3. 3. What is Nagios? <ul><li>Nagios is an open source tool especially developed to monitor hosts and services and designed to inform the network incidents before end-users , clients do. </li></ul><ul><li>It watches hosts and services which we specify and alerts when things go bad and when things get recovered. </li></ul><ul><li>Initially developed for servers and application monitoring , it is now widely used to monitor networks availability. </li></ul>
  4. 4. Features Of Nagios <ul><li>Monitoring of network services (SMTP,POP3,HTTP,NNTP,PING etc) </li></ul><ul><li>Monitoring of host resources (Disk Usage etc) </li></ul><ul><li>Parallelized service checks </li></ul><ul><li>Simple plug-in design that allows users to easily develop their own service checks. </li></ul><ul><li>Contact Notifications when service or host problems occur and get resolved (via email , pager or user-defined method) </li></ul>
  5. 5. Features Continued.. <ul><li>Automatic Log Rotation </li></ul><ul><li>Ability to define network host hierarchy using parent hosts. </li></ul><ul><li>Support for implementing redundant monitoring hosts. </li></ul><ul><li>Optional Web Interface for viewing current network status , notification and problem history , log file etc. </li></ul>
  6. 6. Requirements <ul><li>Things need to get Nagios working are: </li></ul><ul><ul><ul><li>Nagios Plug-ins ( downloadable from nagios url) </li></ul></ul></ul><ul><ul><ul><li>Graphics Libraries </li></ul></ul></ul><ul><ul><ul><li>JPEG Libraries </li></ul></ul></ul><ul><ul><ul><li>Database for storing log files </li></ul></ul></ul>
  7. 7. Architecture & Operation
  8. 8. Architecture <ul><li>Nagios is built on a server/client architecture. </li></ul><ul><li>Usually , on a network , a Nagios server is running on a host , and plugins are running on all the remote hosts that need to be monitored. These plugins send information to the server , which displays them in a GUI. </li></ul><ul><li>Nagios is composed of three parts : </li></ul><ul><ul><ul><li>A Scheduler : this is the server part of nagios. </li></ul></ul></ul><ul><ul><ul><li>At regular interval , the scheduler checks the plugins , and according to their results, do some actions. </li></ul></ul></ul><ul><ul><ul><li>A GUI : the interface of Nagios (with the configuration, the alerts ) . It is generated in web pages generated by CGI. </li></ul></ul></ul><ul><ul><ul><li>The Plugins : They are configurable by the user. They check a service and return a result to the nagios server. </li></ul></ul></ul>
  9. 9. Architecture <ul><li>A Soft Alert is raised when a plug in returns a warning or an error. Then on the GUI ,a green button turns to red. </li></ul><ul><li>When this soft alert is raised many times( the number is configurable) , a hard alert is raised , and the nagios server sends notifications : email , sms, etc. </li></ul>
  10. 10. Nagios Architecture (Internal)
  11. 11. Web Interface – Services Overview
  12. 12. Web Services – Services Details Overview
  13. 13. Configuration Files <ul><ul><ul><li>Nagios.cfg </li></ul></ul></ul><ul><ul><ul><ul><ul><li>Main Configuration File </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Monitored elements configuration </li></ul></ul></ul></ul></ul><ul><ul><ul><li>resource.cfg </li></ul></ul></ul><ul><ul><ul><ul><ul><li>User defined elements configuration file </li></ul></ul></ul></ul></ul><ul><ul><ul><li>cgi.cfg </li></ul></ul></ul><ul><ul><ul><ul><ul><li>Display options for CGI </li></ul></ul></ul></ul></ul><ul><ul><ul><li>host, hostgroup and hostextinfo </li></ul></ul></ul><ul><ul><ul><ul><ul><li>Information concerning monitored equipments </li></ul></ul></ul></ul></ul>
  14. 14. Configuration Files <ul><ul><ul><li>service, servicextinfo </li></ul></ul></ul><ul><ul><ul><ul><ul><li>Information concerning monitored services </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>, service escalation </li></ul></ul></ul></ul></ul><ul><ul><ul><li>host and service dependency </li></ul></ul></ul><ul><ul><ul><ul><ul><li>Dependencies between hosts and between services </li></ul></ul></ul></ul></ul><ul><ul><ul><li>host escalation, host group escalation </li></ul></ul></ul><ul><ul><ul><ul><ul><li>Escalation Notification </li></ul></ul></ul></ul></ul>
  15. 15. Configuration Files <ul><ul><ul><li>contact </li></ul></ul></ul><ul><ul><ul><ul><li>Nagios users. To access Nagios interface, it is necessary to be registered in this contact file </li></ul></ul></ul></ul><ul><ul><ul><li>contactgroup </li></ul></ul></ul><ul><ul><ul><ul><li>User Groups. Notifications and display rights are settled in this file </li></ul></ul></ul></ul><ul><ul><ul><li>Timeperiod </li></ul></ul></ul><ul><ul><ul><ul><li>Use to configure period of time for elements monitoring and users notifications. </li></ul></ul></ul></ul><ul><ul><ul><li>command </li></ul></ul></ul><ul><ul><ul><ul><li>Set of commands used to control services, equipments, events management and notifications </li></ul></ul></ul></ul>
  16. 16. Plugins <ul><li>A plugin is a small program that checks a service ( a daemon , some free space on a disk..). It must return a value and a small line of text. (Nagios will only grab the first line of text). </li></ul><ul><li>Output should be in the format METRIC STATUS : information text/performance data . The allowed METRIC STATUS are 0(OK) , 1(WARNING) , 2(CRITICAL) or 3(UNKNOWN). </li></ul><ul><li>The warning and critical thresholds are parameters , set by the user ,passed as arguments to the plugin. </li></ul><ul><li>The plugins can be run : </li></ul><ul><ul><ul><li>Locally on the Nagios server </li></ul></ul></ul><ul><ul><ul><li>Remotely through a remote Nagios server , with ssh , with snmp , with NRPE (Nagios Remote Plugin Executor) , or with NSCA (Nagios Service Check Acceptor). </li></ul></ul></ul>
  17. 17. <ul><ul><ul><ul><ul><li>QUESTIONS AND ANSWERS </li></ul></ul></ul></ul></ul>
  18. 18. Thank You