1. VIRTUALIZATION & CLOUD COMPUTING
Lecture # 20-21
CSE 423
Defining Cloud computing
Cloud Types

2. Cloud Computing
Cloud computing refers to applications and services that run on a distributed network using virtualized resources and accessed by common Internet protocols and networking standards.
It is distinguished by the notion that resources are virtual and limitless and that details of the physical systems on which software runs are abstracted from the user.

3. Abstraction:
Cloud computing abstracts the details of system implementation from users and developers.
Applications run on physical systems that aren't specified,
data is stored in locations that are unknown,
administration of systems is outsourced to others, and access by users is ubiquitous.

4. Virtualization:
Cloud computing virtualizes systems by pooling and sharing resources.
Systems and storage can be provisioned as needed from a centralized infrastructure,
costs are assessed on a metered basis,
multi-tenancy is enabled,
and resources are scalable with agility.

5. Cloud Types Deployment Model: Service Model Some widely used model
Refers to location and management of the cloud’s infrastructure
Service Model
Consists of particular types of services that can be accessed on cloud computing platform
Some widely used model
NIST Model
The Cloud Cube Model

6. National Institute of Standard and Technology (NIST Definition of Cloud Computing)

7. The Cloud Cube Model
Physical location of the data: Internal (I) / External (E) determines your organization's boundaries.
Ownership: Proprietary (P) / Open (O) is a measure of not only the technology ownership, but of interoperability, ease of data transfer, and degree of vendor application lock-in.
Security boundary: Perimeterised (Per) / De-perimiterised (D-p) is a measure of whether the operation is inside or outside the security boundary or network firewall.
Sourcing: Insourced or Outsourced means whether the service is provided by the customer or the service provider.

9. Deployment Models

10. Public Cloud Private Cloud Hybrid Cloud Community Cloud
Hosted , operated and managed by a third party system owned by organization selling cloud services
Private Cloud
The private cloud infrastructure is operated for the exclusive use of an
organization. The cloud may be managed by that organization or a third
party. Private clouds may be either on- or off-premises.
Hybrid Cloud
A hybrid cloud combines multiple clouds (private, community of public) where those clouds retain their unique identities, but are bound together as a unit.
Community Cloud
A community cloud is one where the cloud has been organized to serve a common function or purpose.
It may be for one organization or for several organizations, but they share common concerns such as their mission, policies, security, regulatory compliance needs, and so on

11. Service Models

12. Infrastructure as a Service(IaaS)
Deliver Infrastructure on Demand in the form of virtual Hardware, Storage and Networking. Virtual Hardware is utilised to provide compute on demand in the form of virtual machine instances
Eg.Amazon EC2, S3, Eucalyptus, GoGrid, Rightspace Cloud
Platform as a Service (PaaS)
Deliver scalable and elastic runtime environments on demand that host the execution of applications.
Backed by core middleware platform for creating abstract environment to deploy and execute application
Software as a service (SaaS)
Provide application and services on demand eg office automation, Photo Editing software, facebook., Twitter accessible through browser on demand

13. Cloud Companies/Service Providers

14. Benefits of Cloud Computing
Lower Computational Costs
Improved Performance
Reduced Software Costs
Instant Software updates
Unlimited storage capacity
Increased Data Reliability
Universal Document Access
Latest version availability
Easier Group Collaboration/ Sharing
Device Independence
Lower computer costs:
You do not need a high-powered and high-priced computer to run cloud computing's web-based applications. Since applications run in the cloud, not on the desktop PC, your desktop PC does not need the processing power or hard disk space demanded by traditional desktop software.
Improved performance:
Computers in a cloud computing system boot and run faster because they have fewer programs and processes loaded into memory…
Reduced software costs:
Instead of purchasing expensive software applications, you can get most of what you need for free.
e.g. most cloud computing applications today, such as the Google Docs suite. better than paying for similar commercial software
which alone may be justification for switching to cloud applications.
Instant software updates:
Another advantage to cloud computing is that you are no longer faced with choosing between obsolete software and high upgrade costs.
When the application is web-based, updates happen automatically available the next time you log into the cloud.
When you access a web-based application, you get the latest version without needing to pay for or download an upgrade.
Unlimited storage capacity:
Cloud computing offers virtually limitless storage.
Your computer's current 1 Tbyte hard drive is small compared to the hundreds of Pbytes available in the cloud.
Increased data reliability:
In a world where few individual desktop PC users back up their data on a regular basis, cloud computing is a data-safe computing platform! if your personal computer crashes, all your data is still out there in the cloud, still accessible
Universal document access:
That is not a problem with cloud computing, because you do not take your documents with you.
Instead, they stay in the cloud, and you can access them whenever you have a computer and an Internet connection
Documents are instantly available from wherever you are
Latest version availability:
When you edit a document at home, that edited version is what you see when you access the document at work.
The cloud always hosts the latest version of your document as long as you are connected, you are not in danger of having an outdated version
Easier group collaboration:
Sharing documents leads directly to better collaboration. Many users do this as it is an important advantages of cloud computing. Multiple users can collaborate easily on documents and projects. Example : sharing excel sheet to fill up by every employee using google docs
Device independence.
You are no longer tethered to a single computer or network. Changes to computers, applications and documents follow you through the cloud. Move to a portable device, and your applications and documents are still available.

15. Disadvantages of Cloud Computing
Requires constant Internet Connection
Does not work well with low speed connection
Stored data might not be Secured
Stored data can be lost
Features might be limited
Requires a constant Internet connection:
Cloud computing is impossible if you cannot connect to the Internet
Does not work well with low-speed connections:
Similarly, a low-speed Internet connection, such as that found with dial-up services, makes cloud computing painful at best and often impossible.
Stored data might not be secure:
With cloud computing, all your data is stored on the cloud. The questions is How secure is the cloud?
Can unauthorised users gain access to your confidential data?
Stored data can be lost:
Theoretically, data stored in the cloud is safe, replicated across multiple machines.
But on the off chance that your data goes missing, you have no physical or local backup.
Features might be limited:
This situation is bound to change, but today many web-based applications simply are not as full-featured as their desktop-based applications. For example, you can do a lot more with Microsoft PowerPoint than with Google Presentation's web-based offering