Cloud environments are often defined by either their deployment model or their service category.
Cloud Deployment Models
The list below details the various cloud deployment models.
- Public — The cloud resources are housed on the premises of the cloud provider, but they are available for use by the public.
- Private — The cloud resources may be housed on the premises of an organization or a third party and are available exclusively to the organization, which may have multiple consumers (e.g. business units or departments).
- Community — The cloud resources are housed on premises or with a third party available exclusively to a community of users. Unlike the Private model, these users may span several different organizations, but they are tied together due to a shared concern or mission.
- Hybrid — The model is a combination of two or more of the other deployment models. A popular use of the Hybrid model is when an organization hosts a Private cloud, but combines it with a Public cloud for other needs. This allows an organization to retain full control of some of its environment.
Cloud Service Categories
There are three categories of cloud services.
Infrastructure as a Service (IaaS)
With this model, a company contracts to use hardware components from a cloud provider. Computing resources, such as networking and storage, are provided over the Internet and come from a pool of resources that are available on demand. A company can control operating systems and applications yet must provide its own security for the resources used, unlike the other two models. This model allows a company to utilize just the right amount of computing resources, again without having to purchase additional equipment. When a growth period is followed by a decline, or a company is forced to scale back operations for other reasons, it can pay for what it will use and not be stuck with idle hardware that can be difficult to repurpose or sell. An example of IaaS is Amazon Elastic Compute Cloud (Amazon EC2).
Platform as a Service (PaaS)
Applications can be developed, managed, and deployed by a company using a platform model. It is especially useful for application development. The platform is offered by the cloud provider, who is responsible for security. Platform as a service can include network, operating systems, storage, and server resources. A cloud provider also handles the configuration of the platform. An example of PaaS is Microsoft Azure.
Software as a Service (SaaS)
Using a web browser, users can access software applications over the Internet using the SaaS model. The cloud provider owns and manages the particular programs that are available with this service. The advantage is that companies do not have to install applications on their own systems, and they pay only for what they use. Costs associated with software deployment, provisioning, licensing, and installation are shifted to the cloud provider. Maintenance and patching are also the responsibility of the cloud provider. This model is heavily reliant on third parties and is especially exposed to any outages or service disruptions that may occur.
The graphic below highlights some examples of cloud services based on their categories.
Concerns With Cloud Computing
Availability is a major concern for any company deciding to use a cloud-computing environment. Whereas an interruption or slow down in Internet access is a concern for any organization, for those reliant on a cloud provider, the Internet connection represents a single point of failure for their operations.
Since security is a shared responsibility with a cloud provider, any strategy or response to an incident carries the additional overhead of coordinating between an organization and its provider.
Being reliant on a third party inherently carries the risk of vendor lock-in, becoming so reliant on the unique services of the provider that you cannot easily transition to somewhere. Further, providers can raise prices or change services with little notice.
Lastly, while always evolving, industry and government regulations might restrict organizations from using cloud providers due to the way resources are shared in cloud computing.
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To test your understanding of the content presented in this assignment, please choose the correct answer.
1. True or False?
Cloud computing helps organizations reduce infrastructure costs.Choose only one answer below.
Correct. This is a true statement. Cloud computing allows organizations to outsource their servers and related infrastructure.
2. Which of the following is a cloud-service category?Choose only one answer below.
a. Software as a Service
b. Platform as a Service
c. Infrastructure as a Service
d. All of the above
Correct. Software as a Service, Platform as a Service, and Infrastructure as a Service are the three categories of cloud services.
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