Phantom: Process Migration in Java

1
Phantom Process Migration in Java

• Chris Serra
• Harit Modi
• Dept. of Computer Sciences

2
Motivation

• Process Migration
• Moving a running process to another host
• Applications
• load balancing
• fault tolerance

3
Outline

• Motivation
• Design Goals
• Implementation
• Future Work
• Conclusions

4
Design Goals

• Phantom
• Pre-emptable
• heterogeneous
• and
• transparent
• object migration

5
Design Goals

• Heterogeneous
• Transparent
• code
• process
• Pre-emptable
• Use either prev slide or this one

6
Spectrum of Possibilities

• Data Migration
• Process Migration
• homogeneous
• heterogeneous
• interpreted
• native

7
Why Java?

• Heterogeneous for free
• Nice properties of language and VM
• type safe
• secure
• widely accepted
• JDK source public
• JVM Debugging (or -ger) Interface

8
Runtime State Components

• data
• objects
• code
• bytecode
• execution state
• call stack
• operand stacks

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Migration Components

• Data
• object serialization
• Code
• class namespace non-uniform globally
• Bytecode interpretation uniform

10
Execution State
Per-method operand stack
Call Stack
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Operand Stack

• Type information missing
• type verification at runtime
• Use dataflow analysis to recreate

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Pointers
Objects
Call Stack
13
Operand Stack - 2

• Object References
• Java objects - pointers
• multiple references
• address space machine-dependent
• temporary objects
• encapsulate using Object Serialization

14
Object Serialization
15
Native Methods

• ltFigure about When we can checkpointgt

16
Future Work

• Checkpointing Policies
• External References

17
Conclusions

• Phantom
• pre-emptable
• heterogeneous
• transparent
• minimal modifications to JDK
• 739
• A
• F