1. Managing a Network with Cricket Jeff Allen WebTV Networks, Inc.

2. First things first… It’s Cricket now!

3. The Problem Monitoring a network is hard: zShort-term issues make us act reactively zNeed data that we often don’t have to make good long-term decisions zLots of types of devices, operating at all levels of the protocol stack

4. Common Questions: Short term: zIs the link to Europe up? Long term: zDo we need more bandwidth to Europe?

5. Better Questions: zWhat is the current state of the link? zWhat has it been recently? zIs it what we expect it to be? zWhat long-term trends can we discern? Answering questions like these requires a good data collection and graphing system.

6. The System:Cricket! Cricket is a tool for storing and viewing time-series data. zVery flexible zExtremely Legible Graphs zSpace and Time efficient zPlatform Independent

7. How it works zCricket’s collector runs from cron every 5 minutes and polls devices. zData is stored in the RRD files. zCricket’s grapher CGI script is used interactively to browse the data. Both the collector and the grapher rely on a hierarchical configuration system called a Config Tree.

8. Collection Cricket gathers data from: zSNMP zShell Scripts zFiles zURL’s zPerl Procedures

9. Storing Data Data lives in Round Robin Database (RRD) files. zAutomatically discards old data, maintaining constant size database. zAutomatically rolls-up data into summaries on various time scales. zUses binary format on disk for speed.

10. Graphing the Data zGraphing is actually done by RRD – thus the very close resemblance to MRTG graphs. zThe graphs are useful because they have: yEnforced data density yEnough info to tell the whole story yThe Right Scale

11. The Config Tree Hierarchical structure for config files: zUses inheritance to avoid repeated configuration info. zEasy to add new targets. zEasy to parallelize collector (and administrators). zCould be used by other apps in the future

12. Future directions zThe capacity to draw 4500 graphs hardly qualifies as a proactive monitoring tool. zHumans must check the graphs now. zWouldn’t be nice if Cricket could check the graphs itself? How would a computer know if a graph “looks right”? zCricket could send traps to an Alert Manager -- but that’s next year’s talk!

13. Contact info: Where: http://www.munitions.com/~jra/cricket You can download it for free from here (under the GPL), and find out about the mailing lists related to Cricket. Who: Jeff Allen