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The past decade has witnessed a dramatic change in the way organizations handle their computing needs. In the 1990s and early 2000s, most enterprises ran their applications on servers that they owned and maintained in their own data centers. But today, cloud computing has come to the forefront.
In fact, the RightScale 2017 Cloud Computing Survey found that 95 percent of the organizations surveyed were using at least one cloud, and 85 percent were using multiple clouds. The average enterprise now runs the majority of its workloads in the cloud: 32 percent of them in the public cloud and 43 percent in a private cloud.
As public, private and hybrid cloud computing has become the norm, businesses have begun to change the ways they think and talk about software and hardware. Now instead of buying an individual application or owning their own IT infrastructure, they often consume computing resources as a cloud service instead. For guidance on which cloud type is right for your business, read our comprehensive guide to cloud computing.
What is Cloud?
Cloud computing is "a style of computing in which scalable and elastic IT-enabled capabilities are delivered as a service using Internet technologies," according to the Gartner research firm. Coud leverages a wide array of key technologies that boost the efficiency of software development, including containers, a method of operating system virtualization that allows consistent app deployment across computing environments.
Furthermore, cloud deployments all offer resource pooling, on-demand self-service, Rapid elasticity, and broad network access. This combination of tools enables the dramatic hyperscaling of cloud computing.
Also important: measured service. Cloud systems automate the process of controlling and optimizing resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth, and active user accounts). Resource usage can be monitored, controlled, and reported, providing transparency for both the provider and consumer of the utilized service. To codify the technical aspects of what a cloud vendor provides, every customer needs a Service Level Agreement.
What is a Cloud Service?
Webopedia defines cloud services as "any service made available to users on demand via the Internet from a cloud computing provider's servers as opposed to being provided from a company's own on-premises servers." Instead of paying a one-time fee to purchase software or hardware outright, organizations purchase cloud services through a subscription. The fees are tied to their usage of the computing resources, and it is easy to scale up or down as they need more or fewer resources.
Most people use cloud services every day — although they may not realize it. If you have Web-based email like Gmail or Outlook.com, that is a cloud service. If you use online office productivity tools like Office 365 or Google Docs, that is a cloud service. If you use a file sharing service like Dropbox or Box, online storage like iCloud or Amazon Drive, online backup like Carbonite or online software like Salesforce, those are all cloud services.
These days, cloud services have become so commonplace that some laptops, such as Chromebooks, are designed to use cloud services almost exclusively, with nearly no software installed on the computer's hard drive other than the operating system.
Some people also use the term “cloud services” to refer to professional services related to the cloud. For example, vendors might offer “cloud services” that help organizations migrate to the cloud, integrate various cloud services, manage cloud workloads or secure their clouds. However, this article will focus on the first definition rather than those sorts of professional services.
How Cloud Services Work
In order to use a cloud service you need two things: 1) a device with an Internet browser and 2) a Web connection. With a cloud service, your data isn't stored on your PC or mobile device, it's stored in the service provider's data center. That means you can pick up where you left off even if you switch devices. Similarly, the applications that you are running aren't saved on your device's hard drive; instead, they are running on the servers in the service provider's data center. Essentially, you are using the computing power of a server that may be hundreds or thousands of miles away, and you are accessing it via the Web.
However, just because you access something via the Web doesn't necessarily make it a cloud service. According to the National Institute of Standards and Technology (NIST), a service has to have five characteristics in order to qualify as a cloud service:
- Broad network access: As already mentioned, anyone can access cloud services from any device with a browser and an Internet connection.
- On-demand self-service: You don't need to call anyone on the phone or have a representative from the vendor help you set up a cloud service; you can simply sign up online and start using it.
- Resource pooling: Resource pooling means that lots of different customers are using the same physical infrastructure. For example, if you use Dropbox, your files are stored on the same hardware that lots of other people's files are on. As an end user, you probably won't be able to tell if a service provider is pooling resources or not.
- Rapid elasticity: If you need to use more or less computing power or storage space or whatever else the vendor is providing, you can do so easily.
- Measured service: The service provider is measuring and tracking how many computing resources you are consuming. In some cases, you will pay higher prices based on your usage, while in others, such as many free cloud services, the price doesn't change.
Source: The Open Group
Benefits of Cloud Services
Organizations choose to use cloud services because they offer a number of benefits that aren’t available with other types of IT environments:
- Agility: For business users, the agility offered by the cloud is one of the biggest arguments in its favor. Organizations can quickly turn services on or off as their needs change with fluctuating market conditions. That enables them to take advantage of business opportunities that they might otherwise miss.
- Scalability: Cloud services can also scale up or down very quickly. If a particular part of a company’s business takes off or slows down, it’s very easy to expand or contract use of the cloud services supporting that part of the business.
- Location Independence: Because cloud services are accessed via the Internet, users aren’t tied to a particular device or a particular location.
- Performance: Cloud services vendors generally offer the most recent versions of software and very up-to-date hardware. In some cases, this means users enjoy faster performance.
- Financial Benefits: While it isn’t always true, using a cloud service often costs less than paying for traditional software or hardware. In addition, organizations avoid some of the costs associated with maintaining, upgrading and securing their applications and infrastructure. Also, with cloud services, organizations are able to avoid some capital expenses and instead have recurring operational expenses.
Main Types of Cloud Services
Cloud services vendors often describe their offerings with a label that ends in the words "as a service." For example, they might offer backup as a service, storage as a service, database as a service or even IT as a service. However, all of these types of cloud services generally fit into one of three major categories: software as a service, platform as a service or infrastructure as a service.
Software as a Service
In the software as a service (SaaS) model, a vendor hosts an application in its own servers, and end users access the software via a browser. Users generally pay a subscription fee for the SaaS — often on a monthly or annual basis.
Because it is delivered via the Web, a SaaS offering can be accessed from anywhere, making it a good option for companies with mobile workers. In addition, the vendor does all the work of maintaining and updating the software as well as the hardware it runs on, and that makes SaaS attractive to companies with small IT teams. SaaS also enables companies to get started quickly and scale easily, which appeals to startups and growing companies.
On the negative side, organizations often don’t have as much opportunity to customize SaaS as with on-premise software. In addition, they often face difficulties integrating their SaaS data with their other applications, and it can be tough to switch vendors after committing to one SaaS supplier. SaaS may also not be a good choice for organizations with stringent compliance requirements or those with security concerns.
Infrastructure as a Service
With infrastructure as a service (IaaS), customers rent access to servers, storage, networking and other hardware that they use to run their applications. The cloud services vendor generally isn’t supplying software, other than perhaps the operating system.
IaaS is a good choice for companies that are developing their own applications, and it is very popular with development teams that need a quick way to set up dev and test environments. It’s also a good option for organizations seeking agility and scalability. Other organizations look to IaaS when they want to keep costs low or when they want to convert some capital expenses into operational expenses.
However, it is helpful to have some cloud expertise when using an IaaS, and it might not be as good an option for organizations that have very small IT teams. Organizations should also be careful to make sure that their IaaS will meet their security and compliance needs.
Platform as a Service
The platform as a service (PaaS) model offers some of the features of SaaS and some of the features of IaaS. While PaaS vendors don’t provide software for end users, they do provide all of the infrastructure and tools that developers might need to create, deploy, manage and secure their own applications. For example, a PaaS designed for Web developers might bundle together an operating system, Web server, content management system, database and other tools along with the compute power and storage necessary for running a website.
Vendors generally market PaaSes to developers, who like them because they make it much faster and easier to get started on a development project. A PaaS offering might not be a good option for smaller organizations without development teams or for organizations with strict compliance and security needs.
The list of leading PaaS vendors is very similar to the list of IaaS vendors, and it includes Amazon Web Services, Microsoft Azure, IBM Bluemix, Google App Engine, Salesforce App Cloud, Red Hat OpenShift, Cloud Foundry and Heroku.