Distributed Logging in Java with Constrained Resource Usage

1
Distributed Logging in Javawith Constrained
Resource Usage

• Sunil Brown Varghese, Daniel Andresen
• Dept. of Computing and Information Sciences
• Kansas State University

2
Overview

• Introduction to Logging
• Distributed Logging
• Distributed Logging with RMI
• Conclusions

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Introduction

• Everyone logs in one way or other
• print(), out, System.out.print() are examples of
  console logging
• Large systems like aircraft monitoring systems,
  transactionbased financial processes may log
  into multiple targets

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Advantages of Logging

• Feedback to developers during development cycles
• Provide system diagnostic alerts from production
  systems
• Provide information for statistical analysis of
  working of a system
• Delivery based on levels of importance could
  improve efficiency in development cycle

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Logging options

• The Log4J Project
• Logging Toolkit for Java from IBM
• Java 2 Standard Edition (v1.4.0 onward)

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Distributed Logging
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Distributed Logging

• Log4j has good support for sending log messages
  to multiple log servers by TCP/IP socket
  connections
• J2SE provides the Java Logging framework by
  default and supports distribution of log messages
  by socket connections (though listeners are left
  to the developer)

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Java Logging Framework
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Observation effects the Observed

• If generated at a high rate, distributed log
  messages may swamp the processor and the network
  connections whereby decreasing system performance
  and the accuracy of the log analysis
• Solution Limit the use of distributed log
  messages to critical and non-repetitive sections
  of code and buffer messages

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Distributed Logging with RMI

• Transmission of Log messages with RMI calls
  allows the log objects to be recorded at remote
  sites as is
• Log messages may be modified easily ( say based
  on network load, exception objects may be removed
  from log)

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Representation
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Extending the Java Logging Framework

• RMI Handler extended from Handler class ensuring
  compatibility with Logger and security in-built
  into Java Logging
• The logging levels may be varied dynamically
  against bandwidth usage by providing level
  information in an XML file

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Class View Client Side
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Class View Server Side
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Sample Levels.xml file

• lt?xml version'1.0'?gt
• ltparam-listgt
• ltcutoffgt1600lt/cutoffgt
• ltcutoffgt1400lt/cutoffgt
• ltcutoffgt1200lt/cutoffgt
• ltcutoffgt1000lt/cutoffgt
• ltcutoffgt800lt/cutoffgt
• ltcutoffgt600lt/cutoffgt
• ltcutoffgt500lt/cutoffgt
• lt/param-listgt

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RMI Log Server

• Instantiates a logger and assigns the RMI Handler
  and other Handlers based on an XML file
• Server binds to the specified machine and port
  (binding data from input XML file)
• This framework allows a chain of RMI Servers to
  be formed connected by RMI Handlers in a tree
  fashion

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Bandwidth Computation

• TCP/IP based weighted average method is used to
  update bandwidth
• Bandwidth is sampled for a Sampling Time and it
  is reset for a fresh start
• If there is no bandwidth updates for an
  Inactivity Tolerance period, the Bandwidth is
  reset

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RMI Log Buffer

• The RMI Handler may buffer the log messages so as
  to reduce the number of RMI calls needed. This
  could dramatically raise the efficiency of
  transmission
• The RMI Buffer ensures message transmission under
  normal RMI Handler operation and abnormal
  termination

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RMI Log Server GUI

• The GUI connects to RMI Log Server and provides
  time graphs of bandwidth statistics
• The cutoffs along with bandwidth variance are
  shown

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RMI Log Server GUI
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RMI Log Server GUI Connection

• As there isnt a unique naming scheme for RMI
  Handlers connected to a logger, the URL and port
  information is used as RMI Handler identifier

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RMI Log Server GUI Connection
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Limitations / Assumptions

• Leveling thresholds at the RMI Handler level are
  to be set intuitively by the user
• Log message sizes were taken as constants for
  testing purposes
• The overhead of making an RMI call is heavier
  than sending data through TCP/IP sockets

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Conclusions

• RMI Logging allows the recreation of log messages
  in remote sites as long as all sub-components
  are serializable
• Allows the exception objects to be stored in
  remote repositories
• RMI Handler can monitor its bandwidth usage and
  discard log messages of low level

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Future work

• RMI Handler may maintain a server list so that if
  one RMI Log Server fails, it retransmits to
  secondary servers
• The GUI interface can be developed further to
  remotely control RMI Log Servers

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Questions ?