You are previewing Nagios, 2nd Edition.

Nagios, 2nd Edition

Cover of Nagios, 2nd Edition by Wolfgang Barth Published by No Starch Press
  1. Nagios: System and Network Monitoring, 2nd Edition
    1. Foreword to the second edition
      1. What's New in the Second Edition?
      2. Information Sources on the Internet
    2. Introduction
      1. The tests
      2. The suppliers of information
      3. Keeping admins up-to-date
      4. Taking in information from outside
      5. Other tools for network monitoring
      6. About This Book
      7. Further notes on the book
      8. Note of Thanks
    3. I. From Source Code to a Running Installation
      1. 1. Installation
      2. 2. Nagios Configuration
      3. 3. Startup
    4. II. In More Detail...
      1. 4. Nagios Basics
      2. 5. Service Checks and How They Are Performed
      3. 6. Plugins for Network Services
      4. 7. Testing Local Resources
      5. 8. Plugins for Special Tasks
      6. 9. Executing Plugins via SSH
      7. 10. The Nagios Remote Plugin Executor (NRPE)
      8. 11. Collecting Information Relevant for Monitoring with SNMP
      9. 12. The Nagios Notification System
      10. 13. Passive Tests with the External Command File
      11. 14. The Nagios Service Check Acceptor (NSCA)
      12. 15. Distributed Monitoring
    5. III. The Web Interface and Other Ways to Visualize Nagios Data
      1. 16. The Classical Web Interface
      2. 17. Flexible Web Interface with the NDOUtils
      3. 18. NagVis
      4. 19. Graphic Display of Performance Data
    6. IV. Part IV Special Applications
      1. 20. Monitoring Windows Servers
      2. 21. Monitoring Room Temperature and Humidity
      3. 22. Monitoring SAP Systems
      4. 23. Processing Events with the EventDB
    7. V. Part V Development
      1. 24. Writing Your Own Plugins
      2. 25. Determining File and Directory Sizes
      3. 26. Monitoring Oracle with the Instant Client
    8. VI. Part VI Appendixes
      1. A. An Overview of the Nagios Configuration Parameters
      2. B. Rapidly Alternating States: Flapping
      3. C. Event Handlers
      4. D. Macros
      5. E. Single Sign-On for the Nagios Web Interface
      6. F. Tips on Optimizing Performance
      7. G. The Embedded Perl Interpreter
      8. H. What's New in Nagios 3.0?
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Chapter 23. Processing Events with the EventDB

Events are fundamentally different from the other, usual host and service states in Nagios. The check of a service in a critical state returns a CRITICAL until the state of the service changes, irrespective of the number of checks and the repeat interval. An event, on the other hand, occurs only once, for instance in the form of a syslog entry or an SNMP trap.

If the events of an uninterruptible power supply (UPS) are logged via syslog to a log file, the message that the UPS has switched to battery because the voltage supply has failed will appear there only once. If you now test regularly whether a corresponding entry occurred within the last half hour, simple log file checks will not announce a match ...

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