towards dynamic resource contractualisation for software components nicolas le sommer valoria...

Towards Dynamic Resource Contractualisation

for Software Components

Nicolas Le Sommer VALORIA Laboratory / University of South Brittany

Nicolas.Le-Sommer@univ-ubs.fr

Plan

Context and problematic

A framework for the contractualisation of resources

The RAJE environment

The JAMUS platform

Conclusion

Perspectives

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Context

Software components are emerging as the new fundamental architectural elements in the software industry.

Development of application programs should be reduced to the selection and the assembling of pre-existing off-the-shelf components.

Development of programs should be made without knowing the implementation details of components (''black box'' approach).

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Context

Functional and non-functional properties of components must be perfectly defined

The current models of software components do not provide functionalities to describe all non-functional properties of components

Example : EJB (Enterprise Java Beans) and CCM (Corba Component Model) only take properties of persistence, transaction an security into account

Non-functional properties of components pertaining to resources are not defined in models of components

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Heterogeneity of resource requirements

● Requires small amount of resources

● Any guarantee regarding resource availability

● Requires small amount of resources

● Any guarantee regarding resource availability

● Requires important amount of resources

● Requires guarantees regarding the resource availability

● Requires important amount of resources

● Requires guarantees regarding the resource availability

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Motivations

To design software components able to

describe their resource requirements dynamically

perceive their execution context in order to adapt their behaviour to this context

To design deployment environments able to

know the resources they have

To determinate whether components can –or cannot– be deployed

take resource requirements of components into account

To provide resource availability guarantees to components in order that components can provide quality of service to users

control resources used by components dynamically

To check whether components use resources as expectedNLS/VALORIA/UBS Component Deployment 2004 -- Edinburgh 6

Contractual and Reflexive Approach

Contractual Approach

Aims at defining and at managing behavioural dependencies between components and their deployment environment

Dependencies pertain to resource access conditions

Reflexive Approach

Aims at allowing components

To analyse their execution conditions using contracts

To define (to modify) their runtime conditions by negotiating (renegotiating) their contracts with their deployment environment

To adapt their behaviour according to the contract terms

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Framework

Architecture of the framework

Contract management

Admission control Component monitoringLayer 2

Resource reification

Monitoring of resources Management of resources

Layer 1

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RAJE

RAJE : Resource-Aware Java Environment

Developed by specializing the first layer of the framework

Based on the Kaffe virtual machine

Provides facilities

to reify resources as objects

to monitor resources and to perform resource access control

to track all resources created by components at runtime

to select precisely the resources that must be monitored or managed

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Monitoring and access control in RAJE

Resource monitoring in RAJE relies on

A polling-based scheme

A notification-based scheme Socket

SocketObserver#1observe()

SocketObservationReport

Composant

write(data)

SocketObserver#2addListener(this)

checkWrite(quotas)

Resource access control in RAJE relies on

A locking-based scheme

An interposition-based schemeSocket

SocketObserver#1lock()/unlock()

Composant write(data)

SocketObserver#2addListener(this)

checkWrite(quotas)

exception

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JAMUS

JAMUS : Java Accommodation of Mobile Untrusted Software

Implemented as a specialization of the second layer of the framework

Platform dedicated to the hosting of untrusted codes

Relies on the RAJE environment

Every component that applies for being hosted must negotiate with the platform a contract defining its resource access conditions

Each component accepted to run is systematically monitored at runtime

To check whether components respect their contract (their resource access conditions)

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Contracts pertaining to resources

clause#1 clause#2

clause#5 clause#4

clause#3

Contract

new FilePattern ("/tmp") new FilePermission(FilePermission.ALL)new FileQuota(30* Mo, 12*Mo)new BestEffort()

new FilePattern ("/tmp") new FilePermission(FilePermission.ALL)new FileQuota(30* Mo, 12*Mo)new BestEffort()

<filesystem> <directory name="/tmp" permissions="ALL" read_quota="12" read_unit="MBytes" write_quota="30" write_unit="MBytes"

availability_constraints = "BestEffort" /></filesystem>

<filesystem> <directory name="/tmp" permissions="ALL" read_quota="12" read_unit="MBytes" write_quota="30" write_unit="MBytes"

availability_constraints = "BestEffort" /></filesystem>

Resource pattern

PermissionsQuotasAllocation mode

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Contract renegotiation

clause#1 clause#2

clause#5 clause#4

Contract

clause#3

Modification#1

clause#7

Ajout#1

clause#6

Amendment

clause#7

Modification

clause#6

Addition

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Negotiation of contracts

Component

submit(contrat1)

JamusCM

canAdmit(clauses1)

Resource Broker

submit(contrat2)canAdmit(clauses2)

okok

nono

subscribe(contrat2) canAdmit(clauses2)

ok

reserve(clauses2)

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Supervision of contracts

ResourceRegister

ResourceTracker

ComponentMonitor

socketComponent

addListener(this)

newResource(socket)

addResource(this)

SocketMonitor

new SocketMonitor (...)

FileMonitor

new FileMonitor (...)

new Socket (...)

read (...)

checkRead (...)

addListener(this)

newResource(socket)

getMonitors()

ResourceAccessException

container

[Monitors]

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Conclusion

A framework that defines the structure of resource contractualisation systems

2 prototypes implemented with our framework

RAJE

Provides facilities to monitor resources and to perform resource access control

JAMUS

Supports dynamic contractualisation of resources

Performs dynamic monitoring of components

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Heterogeneity of deployment platforms

Software heterogeneity

Unix (Linux, xxxBSD, ...)

Windows (95,98, NT, 2000, XP, Pocket PC, ...)

PalmOS, Symbian, QNX, ....

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Hardware heterogeneity

CPU ≈ 100 MhzMemory ≈ 10 Mo

CPU ≈ 400 MhzMemory ≈ 128 Mo

CPU ≈ 3 GhzMemory≈ 512 MoDisk ≈ 80 Go

CPU ≈ 3 GhzMemory ≈ 1 GoDisk ≈ 250 Go

Architecture of JAMUS

RAJE

Con

tain

er

Resource Broker Component Monitoring

Contract Manager

Container Manager

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JAMUS GUI

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JAMUS GUI

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JAMUS GUI

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