I would begin this part two by giving you a recap of what cloud computing is. Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. As mentioned, it is all about the convenient offering of services. It is plainly true that the service requirements of an individual, corporation or a community of people differ in a lot of perspectives. You as an individual may only be on the need for a mail service, a software company, on the other hand, may be looking for an online ever-present platform in which it will be developing and deploying its applications; and so can the service requirements of a community ( maybe a group of organizations or people) vary. The aforementioned issues lead to the categorization of cloud computing into deployment models and service models.
Cloud deployment models deal majorly with who accesses the cloud, i.e. does the public has access to the same cloud service as my organization or it is just my organization alone. Generally, I mean, is the cloud service private or public or hybrid (both public and private) or does it have a community access? The first step in choosing the right cloud solution is to understand the similarities and differences of the four primary deployment models.
A private cloud is a particular model of cloud computing that involves a distinct and secure cloud-based environment in which only the specified client can operate. As with other cloud models, private clouds will provide computing power as a service within a virtualized environment using an underlying pool of physical computing resource. However, under the private cloud model, the cloud (the pool of resource) is only accessible by a single organization providing that organization with greater control and privacy.
Imagine the old way of doing things in an office, where workgroups use hardware and software provisioned specifically for them. I mean, if your company uses Microsoft’s Excel for data science and analysis, then it happens that your finance department uses excel 2013 and for some reason or another, your HR department uses excel 2016. Maybe because a department prefers one version of a product to another. This may lead to a big problem especially for technical designers using products such as AutoCAD where a template prepared in AutoCAD 2013 can be ported to and edited easily in a 2016 version whereas a 2016 version cannot be ported to a previous version. In a private cloud, workgroups or individuals don’t use hardware and software preferred or provisioned specifically to them. Instead, they draw on a pool of shared resources available on demand e.g. they use an online (within the company’s network i.e. intranet) version of maybe Fusion 360 (for technical designing and drawing). This means everyone in the company uses the same version of the software hence intra-company portability is not an issue.
This model is the least disruptive of the four options available. It allows the customers to set-up and manage their own working environments. Private clouds help avoid the culture shock of moving hardware, software, applications and data offsite. This approach also helps calm uneasiness about trusting third parties to handle security, privacy, availability and regulatory compliance. They typically exist behind the company’s firewall. As for the management, an enterprise’s internal IT department, or in some cases an outside service provider, maintains close control of the computing resources, fairly similar to how a traditional data center operates.
They are the other side of the coin of inside-the-firewall private clouds. Consider the’ cloud version’ of Gmail or Outlook. Both I and you has the same level access to the same Gmail servers and we all enjoy all the benefits that come with it e.g. on-demand service and the free Google Drive. A service provider (Google in our case) manages a public cloud, and clients (me and you) typically share resources in a multi-tenancy arrangement, which means they use compartmentalized portions of the same servers and storage systems. But why do people love it so much? In fact, it is gaining more popularity than its most secure private counterpart. The main draw of the public cloud is reduced costs: Multiple tenants share the costs of the underlying infrastructure. In addition, little or no infrastructure investment is required of users, who nevertheless enjoy unprecedented levels of IT service and resource scalability. The result is greater efficiency and increased agility at a relatively low cost.
They are relatively secure though. A company might want to consider this after carefully weighing the balance. Consider the following. A company may subscribe to a specific email service provider (‘private’) to handle its email services. The same company has an option of dealing with the publicly available ESPs like Gmail or Outlook. But using the former is relatively expensive. Yet using the latter is also risky especially in this cyber-age where one can do some serious footprinting (just on the emails alone) and boom, you are a hack victim. The IT guy knows what to do.
You don’t have to be intelligent to tell what a community is. It is simply a group of entities with a common need. If a software development company like Lidmark limited and a group of other similar companies needed a platform for development and deploying similar backboned-apps, then a community cloud may suffice. It is a public cloud variation that alleviates multi-tenancy concerns, in which a relatively small number of organizations with similar needs share a common infrastructure and the associated costs. The savings may be less than when large numbers of public cloud users foot the bill, but the smaller size and shared interests of a community cloud can mitigate privacy, security and compliance fears. Similar to a private cloud, the community option can reside either within an organization’s data center or at an external common site.
There’s also the hybrid cloud model, which mixes and matches the best elements of private, public and community clouds. In simple terms, this cloud infrastructure is a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together by standardized or proprietary technology that enables data and application portability (e.g., cloud bursting). For example, an enterprise may run a private cloud for day-to-day operations but contract for additional resources made available from a public cloud to weather a demand spike.
The best cloud deployment model will depend on several factors, including cost, control, performance, scalability, security and service requirements. May the best for you, win.
This deals with what kinds or types of services are provided by the cloud service providers (CSPs). There are majorly three types of services models e.g. Software as a Service, Platform as a Service, and infrastructure as a Service.
Software as a service (SaaS)
The traditional model of software distribution, in which software is purchased for and installed on personal computers, is sometimes referred to as Software-as-a-Product. Software-as-a-Service, on the other hand, is a software distribution model in which applications are hosted by a vendor or service provider and made available to customers over a network, typically the Internet. Having purchased or acquired freely, a Microsoft office package and installed on your PC is an example of Software as a product. Using google docs online to process your documents and manage spreadsheets is, on the other hand, a cloud’s Software as a Service.
SaaS is becoming an increasingly prevalent delivery model as underlying technologies that support web services and service-oriented architecture (SOA) mature and new developmental approaches become popular. The user doesn’t manage or control the network, servers, OS, storage or applications.
SaaS is also often associated with a pay-as-you-go subscription licensing model (except for those offered for free). Meanwhile, broadband service has become increasingly available to support user access from more areas around the world. Examples are Google’s Gmail and Apps, instant messaging from AOL, Microsoft’s Skype, Yahoo, and Google.It is good from a capital expense viewpoint, but potentially troublesome in terms of flexibility. Applications come as-is, with little or no opportunity for customization. Small- or midsize organizations’ limited budgets and IT staff obviously can benefit from this model. Large enterprises can also benefit from this approach by offloading routine services to a third-party provider and devoting internal resources to strategic and mission-critical activities.
Platform as a Service (PaaS)
PaaS offerings go beyond delivering a pre-packaged application via the cloud. They instead providing the entire computing platform and solutions stack. These platforms are for building and running custom web-based applications and they make all of the facilities required to support the complete life cycle of building and delivering web applications and services entirely available from the Internet, all with no software downloads or installation for developers, IT managers, or end users. This allows enterprises to run custom applications or use the solution’s programming environment to create new solutions. As with SaaS, customers avoid upfront provisioning costs and ongoing expenses for infrastructure maintenance and management. PaaS gives users control of the specific capabilities of their applications as long as the in-house development staff is comfortable with the PaaS provider’s choices for programming languages, interfaces, development tools and database support. Examples include Microsoft’s Azure and Salesforce’s Force. This type of solution may, however, expose you to a vendor-lock-in scenario which makes a customer dependent on a vendor for products and services, unable to use another vendor without substantial switching costs. Lock-in costs which create barriers to market entry may result in antitrust action against a monopoly.
Infrastructure as a service (IaaS)
Infrastructure as a service delivers processing power, security tools, storage capacity and network bandwidth as on-demand services. It is more of the provision of grids or clusters or virtualized servers, processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software, which can include operating systems. The highest profile example is Amazon’s Elastic Compute Cloud (EC2) and Simple Storage Service. As an organization grows, it, therefore, can avoid new investments in these components. IaaS users don’t directly control or have access to the technologies running in the offsite infrastructure; the cloud provider manages these. A core component of most IaaS offerings is the service catalog, an online tool for finding and provisioning available services.
The above three are the major service models offered. Other also do exist including Communication as a Service (CaaS) and the latest DAAS duo comprising of Data as a Service (DaaS) for big data (important for organizations like NASA) and Desktop as a Service (DaaS) for virtual desktop infrastructures. In the next article on cloud computing, we will help you make a decision on whether to move into or away from the cloud -the cloud economics. Stay tuned. For any question, just post as a comment and it will be answered.