The Case for VM-based Cloudlets in Mobile ComputingMahadev Satyanarayanan Paramvir Bahl Ramon Caceres Nigel Davies

Asanka Nissanka

Published in 2009

Only a dream in the mid-1990s Now a reality

“Information at my finger tips at any time and place”

Awaiting discovery is an entirely new world in which mobile computing seamlessly augments the cognitive abilities of users using compute-

intensive capabilities

Natural Language Processing

Computer Vision and Graphics

Speech Recognition

Machine Learning

Augmented Reality

Planning

Decision Making

This Paper

Discuss about technical obstacles of compute-intensive mobile computing

Propose a new system architecture to overcome those obstacles

Discuss deployment challenges of the proposed system

Suggest possible performance improvements to the proposed system

Resource-Poor Mobile Hardware

Mobile hardware is necessarily resource-poor relative to static client and server hardware

Improving size, weight and battery life are higher priorities than enhancing compute power

Cloud Computing for Mobile

Cloud ServicesCellular NetworkMobile Device

Limits of Cloud Computing

Latency Hurts

WAN delays in the critical path of user interaction Humans are acutely sensitive to delay and jitter

Immersive tasks become sluggishWAN

Latency Unlikely

to Improve

Prime targets Bandwidth Security Energy Efficiency Manageability

Transmission of large data sets Wireless Internet (HSDPA) is 2 Mbps

Bandwidth Induced Delays

CloudletsData Center in a Box

Self Managing

Low Power

Consumption

Internet Connectivity

Access Control

How Cloudlets can Help

Nearby resource-rich cloudlet

Mobile device functions as a thin client

Significant computations occur in the cloudlet

Cloudlet vs CloudCloudlet Cloud

State Only soft state Hard and Soft state

Management Self-managed Professionally administered

Environment “Data Center in a box” at business premises

Machine room with power conditioning and cooling

Ownership Decentralized ownership by local business

Centralized ownership by Amazon, Yahoo etc

Network LAN latency/bandwidth Internet latency/bandwidth

Sharing Few users at a time 100s-1000s of users at a time

Transient Cloudlet CustomizationA key challenge is to simplify cloudlet management

Solution is transient customization of cloudlet infrastructure using hardware VM technology

Pre-use customization and Post-use cleanup

Delivering VM state to infrastructure

VM migration approach

Dynamic VM synthesis (Focus of this paper)

Approach 1 : VM MigrationFirst suspend already-executing VM

VM’s processor, disk and memory state are transferred

VM execution is resumed at the destination

Feasibility has been confirmed by

Internet Suspend/Resume (ISR) System

SoulPad

Approach 2 : Dynamic VM Synthesis

Performance is determined solely by local resources

Bandwidth to cloudlet

Compute power of the cloudlet

WAN failures do not affect synthesis

Overlay is delivered from the mobile

Feasibility of Dynamic VM SynthesisKimberley proof-of-concept prototype

Transient binding between device and cloudlet controlled by Kimberley Control Manager (KCM)

Supports browsing and publishing of services using Avahi mechanism in Linux

Uses VirtualBox as VMM

Kimberlize tool is used to create VM overlays

Differences launch VM with base VM to obtain overlay

Dynamic VM SynthesisBindings to Cloudlet Infrastructure

Establish secure TCP tunnel using SSL between KCM on a device and a cloudlet

Cloudlet KCM fetches the VM overlay from mobile

Decrypts and decompress the overlay and apply to the base VM

Launch the VM

Speed of VM Synthesis

VM Overlay is 100-200MB

Takes less than 1min at 100Mbps

Improving Performance

Overlay transmission

Higher-bandwidth short-range wireless network

Decompressing and applying the overlay on Cloudlet

Exploit parallelism to reduce decompression and overlay application times

Partitioning the VM image so that multi-core cloudlet can synthesize the parts

Use caching and prefetching techniques

VM Synthesis Time Depends on

Deployment ChallengesChoosing between bottom-up and top-down deployment

Structuring pricing plans for top-down deployment

Deciding on processing, storage and networking capacity needed

Defining management policies for maximum user experience and minimum cost

Trust and Security

Trust establishment

Reputation based trust

ConclusionResource poverty is a fundamental constraint that severely limits the class of applications that can be run on mobile devices

Connecting to distant cloud over WAN introduces delays and jitter

Connecting to nearby Cloudlet is fast

Proximity of the cloudlet make crisp interactive response for immersive applications that augment human cognition

Rapid customization of cloudlet infrastructure, is achievable through dynamic VM synthesis

Future Work

Explore about performance improvements

Thank YouAny Questions ?