Karim Djemame

• Towards a Definition of Cloud Computing
• Grids and Clouds
• Example of a Cloud Architecture
• Cloud computing - Research Questions
– The Service Oriented Infrastructure Equation
– Interoperability
– Dependability
• Conclusion
2

Towards a Definition of Cloud Computing

• "I think there is a world market for about five computers" —
Remark attributed to Thomas J. Watson (Chairman of the
Board of International Business Machines) – 1943
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• Future internet of services
– World without computers at home and at work
– World with virtual computers/networks
– Various devices used to connect to the future internet of services (e.g. only TV or iPhone and network)
• Change
– No more maintenance of IT infrastructure and
Applications/Data for users,
– But,
• Data is no longer on « your » computer
• Applications are no longer on « your » computer
26/03/2009 Exploring Cloud Computing 5

• Towards a definition of cloud computing
– A Break in the Clouds: Towards a Cloud Definition. Luis M.
Vaquero et al. (January 2009) provides 22 different definitions
• Cloud computing is an information technology infrastructure in which computing resources are virtualized and accessed as a service .
• "Cloud" will be a grand buzzword unifier in IT:
– utility computing, Grid computing, software-as-a-service, and many other scalable remote computing models will get linked to cloud computing.
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Cloud computing – a Definition (2)
• Clouds are a large pool of easily usable and accessible virtualised resources
• These resources can be dynamically reconfigured to adjust to a variable load (scale), allowing also for an optimum resource utilisation
• This pool of resources is typically exploited by a payper-use model in which guarantees are offered by the infrastructure provider by means of customised
Service Level Agreements.
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• Service-Oriented economy is at our door
• Services over the Internet are winning in the market
– Consumers use YouTube, eBay, Amazon, …
– SMEs use hosted Microsoft Exchange, Salesforce.com
– Enterprises routinely rely on remote IT outsourcing
• Services reduce complexity and cost
• Cloud computing providers
– Amazon, Google, Microsoft …
• Service-Oriented Economy requires a Service-
Oriented Infrastructure
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Service
Admin.
Service
Manager
Service
Service
End-user
User Layer
Value Chain
Service
Consumer
Service
Layer Service
Provider
Virtual Execution Environment Management System
Grid Site
Virtualization
Layer
Infrastructure
Provider
Physical
Layer
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Grids vs Clouds

Feature
Resource sharing
Centralisation degree
Usability
QoS guarantees
…
Grid
Collaboration (VOs)
Cloud
Assigned resources not shared
Virtualisation Data and computing resources
Hardware and software platforms
Credential delegations Isolation Security
Architecture SOA
Software dependencies Application domain dependent
Platform awareness
Scalability
Client SW must be Gridenabled
Nodes and sites
User chosen
Application domain independent
Customised environment
Nodes, sites, and hardware
Decentralised control
Hard to manage
Limited support
Centralised
User friendly
Limited support
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• General purpose Grids are typically constructed bottom-up aggregating existing heterogeneous resources
– Interfaces designed to provide combined functionality
• Clouds constructed top-down with a limited, specific set of use cases and modes
– Interfaces are designed to support these and only these
• Clouds can be built on top of Grids
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Portal
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Example of a Cloud Architecture

• Infrastructure as a Service
– Through virtualization, infrastructure providers are able to split, assign and dynamically manage service Providers, that will deploy on these systems the software stacks that run their services
• Platform as a Service
– Instead of supplying a virtualized infrastructure, they can provide the software platform where systems run on
• Software as a Service
– This is an alternative to locally run applications
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Example: Amazon Web Services (AWS)
• EC2 (Elastic Computing Cloud) is the computing service of
Amazon
– Based on hardware virtualisation (Xen)
– Users request virtual machine instances, pointing to an image (public or private)
– Users have full control over each instance (e.g. access as root, if required)
– Request can be issued via SOAP and REST
– X509 certificates
• S3 (Simple Storage Service) is a service for storing and accessing data on the Amazon cloud
– From a user’s point-of-view, S3 is independent from the other Amazon services
– Data is built in a hierarchical fashion, grouped in containers and objects
– Data is accessible via SOAP, REST and BitTorrent
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• Different virtual machines can run different operating systems and multiple applications on the same physical computer.
• The main technology enabling virtualisation is the
Hypervisor
– Virtual Machine Manager (VMM) that partitions a physical host server transparently via emulation or hardwareassisted virtualisation
– This provides a complete simulated hardware environment
– Which Virtual Machine Manager? VMware, XEN…?
• Types of virtualisation?
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• OpenNebula : open source virtual infrastructure engine that enables the dynamic deployment and re-placement of virtual machines on a pool of physical resources
– http://www.opennebula.org/
– From the FP7 RESERVOIR project http://www.reservoir-fp7.eu
• Eucalyptus : Elastic Utility Computing Architecture
– links Programs to Useful Systems
– an open-source software infrastructure for implementing "cloud computing" on clusters
– interface to Eucalyptus is compatible with Amazon's EC2 interface
– http://eucalyptus.cs.ucsb.edu/
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Research Questions

• Integration of virtualization technologies with
Grid computing driven by new techniques for
Business Service Management (BSM)
Virtualization-Aware Grid e.g., VM usage/size as the unit for metering and billing
+
Grid-Aware Virtualization e.g., live migration across administrative domains
+
BSM e.g., policy-based management
= SOI of service-level agreement
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No middleware!!
Resource-side
Grid middleware?
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• Assuming that several cloud computing providers come to be…
• Which interface matter?
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• God loves standards: that’s why he made so many of them
•
• Since “simple is beautiful” …
– if the proposed interfaces by cloud services like AWS are to become popular with Grid users, they might change the standardisation landscape
• HTTP, REST, Xen and BitTorrent are already largely standardised
• What is left at that level
– REST access to storage
– Virtual Image formats
– Instantiation API (perhaps based on REST)
A reference open source implementation is missing
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• Need for dependable services
– Any time access for large but varying number of users
– Service availability crucial

Risk assessment and management as basic service
• Multiple stakeholder perspective
– Users
• Assess and select best services
• Evaluate legal issues and sustainability
• Trust for data security and confidentiality
– Providers
• Analyse, improve and maintain infrastructure
• Compete to attract new users
• Take all measures to ensure permanent service availability
– Telcos
• Compose and offer high quality services
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• Existing Grids have an opportunity to lead the next generation e-Infrastructure by integrating new advancements such as cloud computing
• Hardware virtualisation could lower the operations cost of large infrastructures
• Roadmap should be defined to include cloud technology in current Grid Infrastructures in an incremental and harmonious fashion
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• "I think there is a world market for about five computers" —
Remark attributed to Thomas J. Watson (Chairman of the
Board of International Business Machines) – 1943
• “… In a sense, says Yahoo Research Chief Prabhakar Raghavan, there are only five computers on earth . He lists Google, Yahoo,
Microsoft, IBM, and Amazon . Few others, he says, can turn electricity into computing power with comparable efficiency …”
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• "I think there is a world market for about five computers" —
Remark attributed to Thomas J. Watson (Chairman of the
Board of International Business Machines) – 1943
• “… In a sense, says Yahoo Research Chief Prabhakar
Raghavan, there are only five computers on earth . He lists
Google, Yahoo, Microsoft, IBM, and Amazon . Few others, he says, can turn electricity into computing power with comparable efficiency …”
From Google and the wisdom of clouds , by Steven Baker - BusinessWeek.com
• “… The World Wide Web is becoming one vast, programmable machine. As NYU's Clay Shirky likes to say, Watson was off by four …” – Nicholas Carr
From Wired Magazine Q&A with Nicholas Carr
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