Different types of IT professionals understand the cloud in different ways. For a system administrator, the cloud can provide virtual machines that function as servers in place of or alongside physical servers in the organization’s datacenter. For software developers, the cloud can provide a variety of preconfigured platforms and development environments for application deployment and testing. For a database administrator, the cloud can provide complex storage architectures and preconfigured database management solutions. Cloud services can then organize the data and use artificial intelligence to develop new uses for that data. For user support technicians, the cloud can provide productivity applications and other software, such as Microsoft 365, that are more easily deployed than standalone applications, automatically updated regularly, and accessible on any device platform.
In each of these specializations, cloud services can eliminate the tedious set-up processes that administrators often have to perform before they can get down to work. For example, adding a new physical server to a datacenter can require many separate tasks, including assessing the hardware needs, selecting a vendor, waiting for delivery, assembling the hardware, and installing and configuring the operating system and applications. These tasks can result in days or weeks wasted before the server is even ready for use. With a cloud provider, adding a new virtual server takes only a matter of minutes. A remote management interface, such as the Windows Azure portal shown in Figure 1-1, enables the subscriber to select the desired virtual hardware resources for the server, and within a few minutes, the new server is running and ready for use.
FIGURE 1-1 The Create A Virtual Machine interface in the Microsoft Azure Portal
Describe Microsoft SaaS, IaaS, and PaaS concepts and use cases
The offerings of cloud service providers are typically broken down into service models, which specify what elements of the cloud infrastructure are included with each product. There are three primary cloud service models: Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). Some other products and services use the “as a Service” suffix, such as Desktop as a Service and Data as a Service.
A cloud infrastructure can be broken down into layers forming a stack, as shown in Figure 1-2. The functions of the layers are as follows:
- People The users working with the application
- Data The information that the application creates or utilizes
- Application The top-level software program running on a virtual machine
- Runtime An intermediate software layer, such as .NET or Java, that provides the environment in which applications run
- Middleware A software component that provides intermediate services between an operating system and applications
- Operating system The software that provides the basic functions of a virtual machine
- Virtual network The logical connections between virtual machines running on servers
- Hypervisor The software component on the physical servers that enables virtual machines to share the server’s physical resources
- Servers The physical computers that host the virtual machines that provide cloud services
- Storage The hard drives and other physical components that make up the subsystem providing data storage for the physical servers
- Physical network The cables, routers, and other equipment that physically connect the servers to each other and the Internet
In an organization that uses its own on-premises servers for everything, there is no cloud involved, and the organization is obviously responsible for managing all the layers of the stack. However, when an organization uses cloud-based services, the cloud service provider manages some layers of the stack, and the organization manages the rest. This is called a shared responsibility model. Which layers the organization or provider manages depends on the service model used to furnish the cloud product. The three basic cloud service models are described in the following sections.
FIGURE 1-2 The layers of the cloud infrastructure