1 / 23

An Active Events Model for Systems Monitoring

An Active Events Model for Systems Monitoring. Philip Gross Columbia University Programming Systems Lab Director: Gail Kaiser. Motivation: Loose Coupling. Want to maximize ease of distributed programming Not only should middleware deliver events…

emiliad
Download Presentation

An Active Events Model for Systems Monitoring

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. An Active Events Model for Systems Monitoring Philip Gross Columbia University Programming Systems Lab Director: Gail Kaiser

  2. Motivation: Loose Coupling • Want to maximize ease of distributed programming • Not only should middleware deliver events… • It should completely shield participants from knowledge of each other • Information goes into the cloud, information comes out of the cloud 2

  3. Problem: No Event Context • Consumers get data that they’re “supposed” to get • Confusion and ambiguity can be major problems 3

  4. Example: Stock Trading Program • Sub (MSFT > 80) // sell and cash in • Event published with MSFT = 60: ignored • Event published with MSFT = 1515: received, all shares sold • Are we rich yet? • Unfortunately no: was appointment with MS sales rep at 3:15pm 4

  5. We Conclude That… • We need to associate semantics with event data • Somehow saying “this is what I mean,” or “here’s how to interpret me” • Events that explicitly indicate semantics, we call Active Events, or ActEvents • They’re not just passive data containers 5

  6. Two Flavors of Information Bus • Light model: information is carried by a notification service • High speed, low latency, simple behavior • Heavy model: information is carried by self-transmitting software agents • Lower speed, higher latency, more sophisticated behavior 6

  7. And Two Flavors of ActEvents • By reference or by value • By reference: SmartEvents • Data includes structured tags • External processor maps tags to semantics • By value: Gaugents • Agent ferries not just data… • But also mobile code that has semantic knowledge 7

  8. SmartEvent Implementation • XML embedded in event • Certain tags “exposed” for routing • XML annotated to provide syntactic and semantic information • FleXML (Flexible XML) enables dynamic runtime schema and semantics discovery and composition 8

  9. Initial SmartEvents • Language recognition problem • Validate against Schema • When unknown element encountered, ask “Semantic Server” for • New schema fragment • Processing modules (Tag Processors) • Tag Processors give higher-level events • Supports dynamic schema composition 9

  10. Newer SmartEvents • XML is described with multiple namespaces • Namespaces provide direct syntactic identification • Which allows lookup of Tag Processors • Semantics still looked up dynamically • Still supports dynamic schema composition • Tag Processors can maintain state over event streams 10

  11. Two Flavors of Information Bus • Light model: information is carried by a notification service • High speed, low latency, simple behavior • Heavy model: information is carried by self-transmitting software agents • Lower speed, higher latency, more sophisticated behavior 11

  12. Gaugent Implementation • Specialization of Worklets mobile agents • Worklet Virtual Machine (WVM) installed at each participating node • Java bytecode based • Routing can be altered on the fly • Carries data and processing code 12

  13. Gaugents Continued • Worklets normally carry one junction for each WVM they plan to visit • Encapsulates computation to be performed at that location • Contains semantic information • May carry jackets • Provide a mini-workflow for a particular junction, e.g. repetition, start/exit constraints, etc. • Contain manipulable routing information 13

  14. In Use: KX SmartEvents 14

  15. In Use: KX Gaugents 15

  16. Future Directions • New event system • Extended FleXML • Web services 16

  17. Future Event System • MEEP? CHIEF? • Native XML • Scalability, survivability, performance • VPENs: Virtual Private Event Networks • Event diodes for Multi-Level Security • Content-based routing, but with significant optimizations for topic-based advertisements • GPL 17

  18. Conclusions • Semantic annotation of events is essential for loosely coupled architectures • Different solutions are appropriate for different types of information exchange • We have built two implementations • More experimentation needed 18

  19. Questions? 19

  20. Extended FleXML • Currently one interpretation per incoming event per Metaparser • Multiple consumers may need multiple interpretations • Thus sets of Tag Processors may be applied to produce multiple high-level “interpretations” 20

  21. Web Services • Juggernaut: Sun, IBM, Microsoft all pushing it hard • Has significant implications for service interoperability projects • In particular: SOAP and WSDL 21

  22. SOAP • Very nice encapsulation • Future probe-gauge standard? <env:Envelope xmlns:env="http://www.w3.org/2001/09/soap-envelope"> <env:Header> <n:alertcontrol xmlns:n="http://example.org/alertcontrol"> <n:priority>1</n:priority> <n:expires>2001-06-22T14:00:00-05:00</n:expires> </n:alertcontrol> </env:Header> <env:Body> <m:alert xmlns:m="http://example.org/alert"> <m:msg>Pick up Mary at school at 2pm</m:msg> </m:alert> </env:Body> </env:Envelope> 22

  23. WSDL • Web Services Description Language • Useful for where Pub/Sub meets RPC • Types/Messages • Operation: organize into inputs and outputs • PortType: collection of Operations • Binding: mapping of PortType to e.g. SOAP • Service: set of bound PortTypes at an actual location 23

More Related