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Introduction to Cloud Computing – July 4th, 2011
What is cloud computing to you? (Answers from Class)
Corporate buzz word
Distributed system
A computer on a network
Renting computing resources
Elastic capability
Virtualization application
Scalable
Many people draw comparisons between cloud computing and grid computing[1]
The major differences [2]:
Higher inter-node bandwidth in cloud computing
Critical for distribution/synchronization of large quantities of data
Virtualization
Virtualization of hardware in CC
Virtualization of data in CC
User-facing representation of data is independent of data storage implementation
E.g. Amazon stores stuff over multiple nodes, you do not care how it stores it, just that it is available
Similarities between cloud computing and grid computing
Increased reliability of infrastructure, hardware, and data
Increased flexibility
Reduces cost
Utility computing[3] comprises charging for the use of packaged resources
Does grid computing + utility computing = cloud computing?
Yes and no (check slides – page 6 ) — the answer depends on the definition of cloud computing, which is still under debate [5]
There is a (relatively) universally accepted definition of cloud computing by NIST (see the slide) [6] [11]
What is a snapshot of a machine?
Historical point of time, makes a copy of installed services, programs
Why do we take a snapshot of a system?
Allows administrator to easily mass produce a resource of a specific configuration
Provides a backup of a “healthy” state/template to build other configurations from
Additional notes on the NIST-def’n of cloud computing:
On-demand self-service[7]
Must automate the delegation of resources – this is critical to self-service since humans have a higher probability of committing an error
Digital rights management is better than automation.
We have technology that force legality for digital rights.
Other areas (e.g law) has human that govern the rules (e.g judges)
Ubiquitous network access (Application for multiple devices)
Why support heterogeneous platforms:
Greater market penetration (get more people can access it)
Separation of concerns — must isolate interface (for various devices) from the business logic
Must be mindful of performance capabilities of different types of clients
E.g. phones has less bandwidth than laptops
Resource pooling [8]
Resources are shared by the users
Mutli-tenancy
How do we partition data to isolate each organization’s data from the others?
Table partitioning
Has implications for performance
Has implications for scalability:
Easy to add (set null to everyone)
Not easy to remove/reconfigure data
Security is accomplished by the service provider
Service provider has access to data
Rapid elasticity
Reduce resources to:
Save power (can turn off unused resources)
Free up resources for other users
However there are difficulties in achieving this elasticity:
Incur overhead when increasing/reducing available resources
Should remove state from computational resources (e.g. offset state to a data store so resources can be turned off without loss of data)
Appearance of “unlimited” resource – but can crash from time to time.
Resources are shared, you can scale up while someone scales down
Measured service
Typically do not measure money
Access
No universally well-defined protocol, but all are based on the foundation of HTTP
Virtualization (see notes)
Software-as-a-Service (SaaS):
Service determined by the provider
User does not decide which version to use
E.g You cannot switch to previous version of Google Mail/Docs
SaaS applications are “net native” applications[10]
Disadvantages:
Since provider is in charge of service and data, very tight coupling between the user and the Cloud Service Provider (CSP)
Security is heavily controlled by the CSP (can be both good and bad). User might need to add own security on top of the one provided.
Bandwidth can be bad
Advantages
Security: If there is a fix to a bug fixes are passed to everyone instantly.
Platform-as-a-Service (PaaS)
User creates an application on top of provided platform/environment governed by set of provider-specified rules
Main example of a rule is language specification
Service Provider performs resource management
Infrastructure-as-a-Service (Iaas)
Provider gives users access to computing resources for processing/storage/whatever
There is an illusion that the resources are entirely under your control
The Service Provider still has control and access to the resources
Everything-as-a-Service (XaaS)
Provide capability to write multi-tiered application (i.e. applications on applications)

......

ich version to use
E.g You cannot switch to previous version of Google Mail/Docs
SaaS applications are “net native” applications[10]
Disadvantages:
Since provider is in charge of service and data, very tight coupling between the user and the Cloud Service Provider (CSP)
Security is heavily controlled by the CSP (can be both good and bad). User might need to add own security on top of the one provided.
Bandwidth can be bad
Advantages
Security: If there is a fix to a bug fixes are passed to everyone instantly.
Platform-as-a-Service (PaaS)
User creates an application on top of provided platform/environment governed by set of provider-specified rules
Main example of a rule is language specification
Service Provider performs resource management
Infrastructure-as-a-Service (Iaas)
Provider gives users access to computing resources for processing/storage/whatever
There is an illusion that the resources are entirely under your control
The Service Provider still has control and access to the resources
Everything-as-a-Service (XaaS)
Provide capability to write multi-tiered application (i.e. applications on applications)

Questions
Give an example of a SPI Service that is not flexible. Why is it not flexible?
Facebook. There is only one view of the Facebook homepage. When facebook decides to change the view or add/remove features you are unable to revert back to the old one. All your interactions are going through their current design and view.
Why would you like to exclude human interaction from On-demand self-service?
Any human process introduces change of errors. By excluding the human interaction the fault rate decreases. Also human interactions are slower than automated processes hence improvement both on speed and quality.

References:
[1] http://en.wikipedia.org/wiki/Grid_computing[2] Advanced Topics in Computer Systems: Cloud Computing and Management – 2011(Raouf Boutaba)
[3] http://en.wikipedia.org/wiki/Utility_computing[4] Cloud computing and grid computing 360-degree compared I. Foster et al. 2008
[5] “Twenty Experts Define Cloud Computing”, SYS-CON Media Inc 2008.
[6] http://csrc.nist.gov/groups/SNS/cloud-computing/cloud-def-v15.doc[7] Draft NIST Working Definition of Cloud Computing – 2009, Peter Mell and Tim Grance[8] http://msdn.microsoft.com/en-us/library/aa479086.aspx[9] Visualizing the Boundaries of Control in the Cloud. Dec 2009.
Visualizing the Boundaries of Control in the Cloud
[10] http://www.crn.com/news/applications-os/18831096/how-net-native-software-as-services-differs-from-packaged-apps.htm
[11] http://csrc.nist.gov/publications/drafts/800-145/Draft-SP-800-145_cloud-definition.pdfIntroduction to Cloud Computing – July 4th, 2011
What is cloud computing to you? (Answers from Class)
Corporate buzz word
Distributed system
A computer on a network
Renting computing resources
Elastic capability
Virtualization application
Scalable
Many people draw comparisons between cloud computing and grid computing[1]
The major differences [2]:
Higher inter-node bandwidth in cloud computing
Critical for distribution/synchronization of large quantities of data
Virtualization
Virtualization of hardware in CC
Virtualization of data in CC
User-facing representation of data is independent of data storage implementation
E.g. Amazon stores stuff over multiple nodes, you do not care how it stores it, just that it is available
Similarities between cloud computing and grid computing
Increased reliability of infrastructure, hardware, and data
Increased flexibility
Reduces cost...