CLOUD COMPUTING AND VIRTUALIZATION

1. CLOUD COMPUTING AND VIRTUALIZATION

2. CLOUD COMPUTING • In the simplest terms, cloud computing means storing and accessing data and programs over the Internet instead of your computer's hard drive. • In computer networking ,cloud computing is a phrase used to describe a variety of concepts that involve a large number of computers connected through a communication network such as the Internet.

3. Cloud computing….. • The phrase is often used in reference to network-based services, which appear to be provided by real server hardware, and are in fact served up by virtual hardware, simulated by software running on one or more real machines. Such virtual servers do not physically exist and can therefore be moved around and scaled up or down on the fly without affecting the end user, somewhat like a cloud becoming larger or smaller without being a physical object.

4. Cloud computing….. • In common usage, the term "the cloud" is essentially a metaphor for the Internet. Marketers have further popularized the phrase "in the cloud" to refer to software, platforms and infrastructure that are sold "as a service" i.e. remotely through the Internet. Typically, the seller has actual energy-consuming servers which host products and services from a remote location, so end-users don't have to; they can simply log on to the network without installing anything. The major models of cloud computing service are known as software as a service, platform as a service, and infrastructure as a service. These cloud services may be offered in a public, private or hybrid network. • ex:Google, Amazon, Oracle Cloud, Salesforce, Zoho, Access2MyPC, and Microsoft Azure are some well-known cloud vendors.

5. CHARACTERISTICS • Characteristics • Cloud computing exhibits the following key characteristics: • Agility improves with users' ability to re-provision technological infrastructure resources. • Application programming interface(API) accessibility to software that enables machines to interact with cloud software in the same way that a traditional user interface (e.g., a computer desktop) facilitates interaction between humans and computers.

6. Characteristics cont…. • Device and location independence enable users to access systems using a web browser regardless of their location or what device they use (e.g., PC, mobile phone). As infrastructure is off-site (typically provided by a third-party) and accessed via the Internet, users can connect from anywhere. • Virtualization technology allows sharing of servers and storage devices and increased utilization. Applications can be easily migrated from one physical server to another. • Reliability improves with the use of multiple redundant sites, which makes well-designed cloud computing suitable for business continuity and disaster recovery • Performance is monitored, and consistent and loosely coupled architectures are constructed using web services as the system interface.

7. Characteristics cont…. • Maintenance of cloud computing applications is easier, because they do not need to be installed on each user's computer and can be accessed from different places. • Security can improve due to centralization of data, increased security-focused resources, etc., but concerns can persist about loss of control over certain sensitive data, and the lack of security for stored kernels. Security is often as good as or better than other traditional systems, in part because providers are able to devote resources to solving security issues that many customers cannot afford to tackle.

8. However, the complexity of security is greatly increased when data is distributed over a wider area or over a greater number of devices, as well as in multi-tenant systems shared by unrelated users. In addition, user access to security audit logs may be difficult or impossible. Private cloud installations are in part motivated by users' desire to retain control over the infrastructure and avoid losing control of information security.

9. Advantages of cloud computing • Cloud computing relies on sharing of resources to achieve coherence and economies of scale, similar to a utility over a network. At the foundation of cloud computing is the broader concept of converged infrastructure and shared services. • The cloud also focuses on maximizing the effectiveness of the shared resources. • Cloud resources are usually not only shared by multiple users but are also dynamically reallocated per demand.

10. For example, a cloud computer facility that serves European users during European business hours with a specific application (e.g., email) may reallocate the same resources to serve North American users during North America's business hours with a different application (e.g., a web server). • "moving to cloud" also refers to an organization moving away from a traditional CAPEX model (buy the dedicated hardware and depreciate it over a period of time) to the OPEX model (use a shared cloud infrastructure and pay as one uses it).

11. Proponents claim that cloud computing allows companies to avoid upfront infrastructure costs, and focus on projects that differentiate their businesses instead of infrastructure. • Hosted services • The term "cloud computing" is mostly used to sell hosted services in the sense of application service provisioning that run client server software at a remote location. Such services are given popular acronyms like 'SaaS' (software as a service), 'PaaS' (platform as a service), 'IaaS' (infrastructure as a service), 'HaaS' (hardware as a service) and finally 'EaaS' (everything as a service). End users access cloud-based applications through a web browser, thin client or mobile app while the business software and user's data are stored on servers at a remote location. Examples include Amazon Web Services and Google App engine, which allocate space for a user to deploy and manage software "in the cloud".

12. The origin of the term cloud computing is unclear, although it is often attributed to the Internet Systems Division of Compaq Computer (George Favaloro, Philip Reagan, Jeff Whatcott, Ken Evans, Ricardo Cidale, and others).The expression cloud is commonly used in science to describe a large agglomeration of objects that visually appear from a distance as a cloud and describes any set of things whose details are not inspected further in a given context. • Meteorology: a weather cloud is an agglomeration. • Mathematics: a large number of points in a coordinate system in mathematics is seen as a point cloud; • Astronomy: a cloud of gas and particulate matter in space is known as a nebula (Latin for mist or cloud), • Physics: The indeterminate position of electrons around an atomic kernel appears like a cloud to a distant observer

13. In analogy to above usage the word cloud was used as a metaphor for the Internet and a standardized cloud-like shape was used to denote a network on telephony schematics and later to depict the Internet in computer network diagrams. • The cloud symbol was used to represent the Internet as early as 1994, in which servers were then shown connected to, but external to, the cloud. • References to cloud computing in its modern sense can be found as early as 1996, with the earliest known mention to be found in a Compaq internal document. • The term became popular after Amazon.com introduced the Elastic Compute Cloud in 2006.

14. THE HISTORY OF CLOUD COMPUTING • The 1950s • The underlying concept of cloud computing dates back to the 1950s, when large-scale mainframe computers became available in academia and corporations, accessible via thin clients/terminal computers, often referred to as "static terminals", because they were used for communications but had no internal processing capacities. To make more efficient use of costly mainframes, a practice evolved that allowed multiple users to share both the physical access to the computer from multiple terminals as well as the CPU time

15. As computers became more prevalent, scientists and technologists explored ways to make large-scale computing power available to more users through time-sharing, experimenting with algorithms to provide the optimal use of the infrastructure, platform and applications which prioritized the CPU and efficiency for the end users. • Since 2000

16. John McCarthy opined in the 1960s that "computation may someday be organized as a public utility."Almost all of the modern-day characteristics of cloud computing (elastic provision, provided as a utility, online, illusion of infinite supply), the comparison to the electricity industry and the use of public, private, government, and community forms, were thoroughly explored in Douglas Parkhill's 1966 book, The Challenge of the Computer Utility. Other scholars have shown that cloud computing's roots go all the way back to the 1950s when scientist Herb Grosch (the author of Grosch's law) postulated that the entire world would operate on dumb terminals powered by about 15 large data centers. Due to

17. In the 1990s, telecommunications companies, who previously offered primarily dedicated point-to-point data circuits, began offering virtual private network (VPN) services with comparable quality of service, but at a lower cost. By switching traffic as they saw fit to balance server use, they could use overall network bandwidth more effectively. They began to use the cloud symbol to denote the demarcation point between what the provider was responsible for and what users were responsible for. Cloud computing extends this boundary to cover servers as well as the network infrastructure.

18. VIRTUALIZATION

19. Definition • Definition: Virtualization is the creation of a virtual (rather than actual) version of something, such as an operating system, a server, a storage device or network resources.

20. Description • You can host a guest operating system known as a VM inside your main operating system known as the host sharing the computing resources from your pc such as the CPU and memory and this will allow you to have access to other operating systems in real time • Testing and learning. If you are a software developer, you can test software inside a VM. If the VM would or ever crash your operating system due to your software, then the main operating system is not affected, only the VM would be. And it’s also good for network testing for network engineers.

21. If you have a server with lots of computing resources then you could create lots of webservers which are separate to each other and resell what they call 'virtual server' to customers. This means they get a slice of your computer resources. If their webserver shuts down abnormally, the machine would not be affected as you they will only have access to their virtual machine.eg If you have more than one monitor, then you can each assign a virtual machine to a monitor so each virtual machine has its own monitor.

22. VMs are portable. It’s just a huge file. Take that file with you anywhere and you have your files and operating with u wherever you go. However you can only run it on a pc that has a Virtualization software, software that allows you to run virtual machines for example virtual box and VMware versions

23. Disadvantages • Disadvantages:  • Resources Hungry. It uses up more resources the more VMs that you run simultaneously.  • If your CPU does not allow for hardware virtualization then you can run some operating systems in software virtualization but generally it’s slower. So slow that it would annoy you. That’s to say some operating systems will not run in software virtualization and require that you have a CPU with hardware virtualization. So it would cost you more if you don’t have a CPU with hardware virtualization. 

24. Virtualizationtechnology allows sharing of servers and storage devices and increased utilization. Applications can be easily migrated from one physical server to another. • Multitenancy enables sharing of resources and costs across a large pool of users thus allowing for: • centralization of infrastructure in locations with lower costs (such as real estate, electricity, etc.) • peak-load capacity increases (users need not engineer for highest possible load-levels) • utilisation and efficiency improvements for systems that are often only 10–20% utilised.[Reliabilityimproves with the use of multiple redundant sites, which makes well-designed cloud computing suitable for business continuity and disaster recovery.[45] • Scalability and elasticity via dynamic ("on-demand") provisioning of resources on a fine-grained, self-service basis near real-time(Note, the VM startup time varies by VM type, location, os and cloud providers), without users having to engineer for peak loads.[Performanceis monitored, and consistent and loosely coupled architectures are constructed using web services as the system interface.

25. Security can improve due to centralization of data, increased security-focused resources, etc., but concerns can persist about loss of control over certain sensitive data, and the lack of security for stored kernels.Security is often as good as or better than other traditional systems, in part because providers are able to devote resources to solving security issues that many customers cannot afford to tackle.[However, the complexity of security is greatly increased when data is distributed over a wider area or over a greater number of devices, as well as in multi-tenant systems shared by unrelated users. In addition, user access to security audit logs may be difficult or impossible. Private cloud installations are in part motivated by users' desire to retain control over the infrastructure and avoid losing control of information security.

26. Maintenance of cloud computing applications is easier, because they do not need to be installed on each user's computer and can be accessed from different places. • If you want to own your own server and intend to resell a virtual server then you generally need a fair bit of money to set it all up. This could mean a purchase of 64-bit hardware with multiple cpus and multiple hard drives.

27. Slides prepared by engineer saxon and william See you people in the next lecturer