Cloud Computing
Abstract
Cloud computing promises to increase the velocity with which applications are deployed, increase innovation, and lower costs, all while increasing business agility. Sun takes an inclusive view of cloud computing that allows it to support every facet, including the server, storage, network, and virtualization technology that drive cloud computing environments to the software that runs in virtual appliances that can be used to assemble applications in minimal time. This term paper discusses how cloud computing transforms the way we design, build, and deliver applications, and the architectural considerations that enterprises must make when adopting and using cloud computing technology.
Introduction
Everyone has an opinion on what is cloud computing. It can be the ability to rent a server or a thousand servers and run a geophysical modeling application on the most powerful systems available anywhere. It can be the ability to rent a virtual server, load software on it, turn it on and off at will, or clone it ten times to meet a sudden workload demand. It can be storing and securing immense amounts of data that is accessible only by authorized applications and users. It can be supported by a cloud provider that sets up a platform that includes the OS, Apache, MySQL database, Perl, Python, and PHP with the ability to scale automatically in response to changing workloads. Cloud computing can be the ability to use applications on the Internet that store and protect data while providing a service — anything including email, sales force automation and tax preparation. It can be using a storage cloud to hold application, business, and personal data. And it can be the ability to use a handful of Web services to integrate photos, maps, and GPS information to create a mash up in customer Web browsers.
The Nature of Cloud Computing
Building on established trends
Cloud computing builds on established trends for driving the cost out of the delivery of services while increasing the speed and agility with which services are deployed. It shortens the time from sketching out application architecture to actual deployment. Cloud computing incorporates virtualization, on-demand deployment, Internet delivery of services, and open source software. From one perspective, cloud computing is nothing new because it uses approaches, concepts, and best practices that have already been established. From another perspective, everything is new because cloud computing changes how we invent, develop, deploy, scale, update, maintain, and pay for applications and the infrastructure on which they run. Here in this term paper, we examine the trends and how they have become core to what cloud computing is all about.
Virtual machines as the standard deployment object
Over the last several years, virtual machines have become a standard deployment object. Virtualization further enhances flexibility because it abstracts the hardware to the point where software stacks can be deployed and redeployed without being tied to a specific physical server. Virtualization enables a dynamic datacenter where servers provide a pool of resources that are harnessed as needed, and where the relationship of applications to compute, storage, and network resources changes dynamically in order to meet both workload and business demands. With application deployment decoupled from server deployment, applications can be deployed and scaled rapidly, without having to first procure physical servers. Virtual machines have become the prevalent abstraction — and unit of deployment — because they are the least-common denominator interface between Service providers and developers. Using virtual machines as deployment objects is sufficient for 80 percent of usage, and it helps to satisfy the need to rapidly deploy and scale applications. Virtual appliances, virtual machines that include software that is partially or fully configured to perform a specific task such as a Web or database server, further enhance the ability to create and deploy applications rapidly. The combination of virtual machines and appliances as standard deployment objects is one of the key features of cloud computing. Compute clouds are usually complemented by storage clouds that provide virtualized storage through APIs that facilitate storing virtual machine images, source files for components such as Web servers, application state data, and general business data.
The on-demand, self-service, pay-by-use model
The on-demand, self-service, pay-by-use nature of cloud computing is also an extension of established trends. From an enterprise perspective, the on-demand nature of cloud computing helps to support the performance and capacity aspects of service-level objectives. The self-service nature of cloud computing allows organizations to create elastic environments that expand and contract based on the workload and target performance parameters. And the pay-by-use nature of cloud computing may take the form of equipment leases that guarantee a minimum level of service from a cloud provider.
Virtualization is a key feature of this model. IT organizations have understood for years that virtualization allows them to quickly and easily create copies of existing environments —sometimes involving multiple virtual machines to support test, development, and staging activities. The cost of these environments is minimal because they can coexist on the same servers as production environments because they use few resources. Likewise, new applications can be developed and deployed in new virtual machines on existing servers, opened up for use on the Internet, and scaled if the application is successful in the marketplace. This lightweight deployment model has already led to a “Darwinistic” approach to business development where beta versions of software are made public and the market decides which applications deserve to be scaled and developed further or quietly retired. Cloud computing extends this trend through automation. Instead of negotiating with an IT organization for resources on which to deploy an application, a compute cloud is a self-service proposition where a credit card can purchase compute cycles, and a Web interface or API is used to create virtual machines and establish network relationships between them. Instead of requiring a long-term contract for services with an IT organization or a service provider, clouds work on a pay-by-use, or payby-the-sip model where an application may exist to run a job for a few minutes or hours, or it may exist to provide services to customers on a long-term basis. Compute clouds are built as if applications are temporary, and billing is based on resource consumption: CPU hours used, volumes of data moved, or gigabytes of data stored. The ability to use and pay for only the resources used shifts the risk of how much infrastructure to purchase from the organization developing the application to the cloud provider. It also shifts the responsibility for architectural decisions from application architects to developers. This shift can increase risk, risk that must be managed by enterprises that have processes in place for a reason, and of system, network, and storage architects that needs to factor in to cloud computing designs. Infrastructure is programmable. This shift of architectural responsibility has significant consequences. In the past, architects would determine how the various components of an application would be laid out onto a set of servers, how they would be interconnected, secured, managed, and scaled. Now, a developer can use a cloud provider’s API to create not only an application’s initial composition onto virtual machines, but also how it scales and evolves to accommodate workload changes.
Consider this analogy: historically, developer writing software using the JAVA programming language determines when it’s appropriate to create new threads to allow multiple activities to progress in parallel. Today, a developer can discover and attach to a service with the same ease, allowing them to scale an application to the point where it might engage thousands of virtual machines in order to accommodate a huge spike in demand. The ability to program application architecture dynamically puts enormous power in the hands of developers with a commensurate amount of responsibility. To use cloud computing most effectively, a developer must also be an architect, and that architect needs to be able to create a self-monitoring and self-expanding application. The developer/architect needs to understand when it’s appropriate to create a new thread versus create a new virtual machine, along with the architectural patterns for how they are interconnected. When this power is well understood and harnessed, the results can be spectacular. The importance of this shift from developer to developer/architect cannot be understated. Consider whether your enterprise datacenter could scale an application this rapidly to accommodate such a rapidly growing workload, and whether cloud computing could augment your current capabilities.
Applications are composed and are built to be composable
Another consequence of the self-service, pay-by-use model is that applications are composed by assembling and configuring appliances and open-source software as much as they are programmed. Applications and architectures that can be refactored in order to make the most use of standard components are those that will be the most successful in leveraging the benefits of cloud computing. Likewise, application components should be designed to be composable by building them so they can be consumed easily. This requires having simple, clear functions, and well-documented APIs. Building large, monolithic applications is a thing of the past as the library of existing tools that can be used directly or tailored for a specific use becomes ever larger.
Even large corporations can use cloud computing in ways that solve significant problems in less time and at a lower cost than with traditional enterprise computing.
Example Web application deployment
As an example of how the combination of virtualization and self service facilitate application deployment, consider a two-tier Web application deployment into a cloud.
1. A developer might choose a load balancer, Web server, and database server appliances from a library of preconfigured virtual machine images.
2. The developer would configure each component to make a custom image. The load balancer would be configured, the Web server populated with its static content by uploading it to the storage cloud, and the database server appliances populated with dynamic content for the site.
3. The developer layers custom code into the new architecture, making the components meet specific application requirements.
4. The developer chooses a pattern that takes the images for each layer and deploys them, handling networking, security, and scalability issues.
5. The secure, high-availability Web application is up and running. When the application needs to be updated, the virtual machine images can be updated, versioned, copied across the development-test-production chain, and the entire infrastructure redeployed. Cloud computing assumes that everything is temporary, and it’s just as easy to redeploy an entire application than it is to manually patch a set of individual virtual machines.
Services are delivered over the network
It almost goes without saying that cloud computing extends the existing trend of making services available over the network. Virtually every business organization has recognized the value of Web-based interfaces to their applications, whether they are made available to customers over the Internet, or whether they are internal applications that are made available to authorized employees, partners, suppliers, and consultants. The beauty of Internet-based service delivery, of course, is that applications can be made available anywhere, and at any time. While enterprises are well aware of the ability to secure communications using Secure Socket Layer (SSL) encryption along with strong authentication, bootstrapping trust in a cloud computing environment requires carefully considering the differences between enterprise computing and cloud computing. When properly architected, Internet service delivery can provide the flexibility and security required by enterprises of all sizes.
Cloud computing Architecture
Cloud architecture, the systems architecture of the software systems involved in the delivery of cloud computing, comprises hardware and software designed by a cloud architect who typically works for a cloud integrator. It typically involves multiple cloud components communicating with each other over application programming interfaces, usually web services. Complexity is controlled and the resulting systems are more manageable than their monolithic counterparts.
Cloud architecture extends to the client, where web browsers and/or software applications access cloud applications. Cloud storage architecture is loosely coupled, where metadata operations are centralized enabling the data nodes to scale into the hundreds, each independently delivering data to applications or users
Cloud computing can describe services being provided at any of the traditional layers from hardware to applications. In practice, cloud service providers tend to offer services that can be grouped into three categories: software as a service, platform as a service, and infrastructure as a service. These categories group together the various layers, with some overlap.
Cloud computing infrastructure models
Public clouds
Public clouds are run by third parties, and applications from different customers are likely to be mixed together on the cloud’s servers, storage systems, and networks. Public clouds are most often hosted away from customer premises, and they provide a way to reduce customer risk and cost by providing a flexible, even temporary extension to enterprise infrastructure. If a public cloud is implemented with performance, security, and data locality in mind, the existence of other applications running in the cloud should be transparent to both cloud architects and end users. Indeed, one of the benefits of public clouds is that they can be much larger than a company’s private cloud might be, offering the ability to scale up and down on demand, and shifting infrastructure risks from the enterprise to the cloud provider, if even just temporarily. Portions of a public cloud can be carved out for the exclusive use of a single client, creating a virtual private datacenter. Rather than being limited to deploying virtual machine images in a public cloud, a virtual private datacenter gives customers greater visibility into its infrastructure. Now customers can manipulate not just virtual machine images, but also servers, storage systems, network devices, and network topology. Creating a virtual private datacenter with all components located in the same facility helps to lessen the issue of data locality because bandwidth is abundant and typically free when connecting resources within the same facility.
Private clouds
Private clouds are built for the exclusive use of one client, providing the utmost control over data, security, and quality of service. The company owns the infrastructure and has control over how applications are deployed on it. Private clouds may be deployed in an enterprise datacenter, and they also may be deployed at a collocation facility. Private clouds can be built and managed by a company’s own IT organization or by a cloud provider. In this “hosted private” model, a company such as Sun can install, configure, and operate the infrastructure to support a private cloud within a company’s enterprise datacenter. This model gives companies a high level of control over the use of cloud resources while bringing in the expertise needed to establish and operate the environment.
Hybrid clouds
Hybrid clouds combine both public and private cloud models. They can help to provide on-demand, externally provisioned scale. The ability to augment a private cloud with the resources of a public cloud can be used to maintain service levels in the face of rapid workload fluctuations. This is most often seen with the use of storage clouds to support Web 2.0 applications. A hybrid cloud also can be used to handle planned workload spikes. Sometimes called “surge computing,” a public cloud can be used to perform periodic tasks that can be deployed easily on a public cloud. Hybrid clouds introduce the complexity of determining how to distribute applications across both a public and private cloud. Among the issues that need to be considered is the relationship between data and processing resources. If the data is small, or the application is stateless, a hybrid cloud can be much more successful than if large amounts of data must be transferred into a public cloud for a small amount of processing.
Cloud computing benefits
In order to benefit the most from cloud computing, developers must be able to refactor their applications so that they can best use the architectural and deployment paradigms that cloud computing supports. The benefits of deploying applications using cloud computing include reducing run time and response time, minimizing the risk of deploying physical infrastructure, lowering the cost of entry, and increasing the pace of innovation.
Reduce run time and response time
For applications that use the cloud essentially for running batch jobs, cloud computing makes it straightforward to use 1000 servers to accomplish a task in 1/1000 the time that a single server would require.
For applications that need to offer good response time to their customers, refactoring applications so that any CPU-intensive tasks are farmed out to ‘worker’ virtual machines can help to optimize response time while scaling on demand to meet customer demands.
Minimize infrastructure risk
IT organizations can use the cloud to reduce the risk inherent in purchasing physical servers. When pushing an application out to the cloud, scalability and the risk of purchasing too much or too little infrastructure becomes the cloud provider’s issue. In a growing number of cases, the cloud provider has such a massive amount of infrastructure that it can absorb the growth and workload spikes of individual customers, reducing the financial risk they face. Another way in which cloud computing minimizes infrastructure risk is by enabling surge computing, where an enterprise datacenter (perhaps one that implements a private cloud) augments its ability to handle workload spikes by a design that allows it to send overflow work to a public cloud. Application lifecycle management can be handled well in an environment where resources are no longer scarce, and where resources can be better matched to immediate needs, and at lower cost.
Lower cost of entry
There are a number of attributes of cloud computing that help to reduce the cost to enter new markets:
• Because infrastructure is rented, not purchased, the cost is controlled, and the capital investment can be zero. In addition to the lower costs of purchasing compute cycles and storage “by the sip,” the massive scale of cloud providers helps to minimize cost, helping to further reduce the cost of entry.
• Applications are developed more by assembly than programming. This rapid application development is the norm, helping to reduce the time to market, potentially giving organizations deploying applications in a cloud environment a head start against the competition.
Increased pace of innovation
Cloud computing can help to increase the pace of innovation. The low cost of entry to new markets helps to level the playing field, allowing start-up companies to deploy new products quickly and at low cost. This allows small companies to compete more effectively with traditional organizations whose deployment process in enterprise datacenters can be significantly longer. Increased competition helps to increase the pace of innovation — and with many innovations being realized through the use of open source software, the entire industry serves to benefit from the increased pace of innovation that cloud computing promotes.
Results
- Cloud computing is more than SaaS - Although Software as a Service (SaaS) is an important component of cloud computing, respondents ranked SaaS behind Platform as a Service (PaaS) and Infrastructure as a Service (IaaS) as the most important components of cloud computing.
- Core cloud computing technologies - Enterprises employ a wide range of technologies in their cloud computing platforms. Access Control was the top concern for people, whereby 90 percent of respondents named Access Control as somewhat/very important for building the cloud. Network Security and Virtualization were also named as key technologies.
- Cloud computing influencers - The people within the enterprise that influence cloud computing decisions go well beyond IT. Respondents named IT, application development, and line of business (LOB) stakeholders as the top influencers for cloud computing decisions.
Conclusion
Cloud computing is the next big wave in computing. It has many benefits, such as better hardware management, since all the computers are the same and run the same hardware. It also provides for better and easier management of data security, since all the data is located on a central server, so administrators can control who has and doesn't have access to the files.
There are some down sides as well to cloud computing. Peripherals such as printers or scanners might have issues dealing with the fact that there is no hard drive attached to the physical, local machine. If there are machines a user uses at work that aren't their own for any reason, that require access to particular drivers or programs, it is still a struggle to get this application to know that it should be available to the user.
If you're looking to implement this, you have two options. You can host it all within your network, or you can use a device from a company that provides the server storage.
References
http://www.networkworld.com/news/2009/052109-mit-cloud.html
Stanford University: http://www.youtube.com/watch?v=Le8WhRS3TNg
http://www.microsoft.com/virtualization/cloud-computing/default.mspx
http://en.wikipedia.org/wiki/Cloud_computing
http://www.infoworld.com/d/cloud-computing/what-cloud-computing-really-means-031
http://www.wikinvest.com/concept/Cloud_Computing
http://www.sun.com/solutions/cloudcomputing/index.jsp
