⁠Chapter 1. Cloud Concepts

1.1. An Introduction into Cloud Services using Fedora

1.1.1. What is Cloud Computing
1.1.2. Types of Cloud Services

⁠1.1. An Introduction into Cloud Services using Fedora

⁠1.1.1. What is Cloud Computing

Pardon the pun, but "the cloud" is a nebulous term. When well-meaning people talk about cloud computing, they are often talking about one of many difference scenarios. In this section, we'll explore using Fedora and various aspects of cloud computing.

⁠1.1.2. Types of Cloud Services

There are various types of cloud services. The service models are defined by how much of the computing stack is provided as a service, and how much is provided to the user as a capabilty.

⁠1.1.2.1. Infrastructure as a Service

Infrastructure as a Service (IaaS) is a service model that provides machine level resources to the user. The "infrastructure" consists of configurable storage, network connectivity, processing power, and a basic operating system image. The user then can configure the operating system to suit their needs, without the overhead required for management of the hardware and virtualization technology the operating system runs on.

Fedora works at the infrastructure layer, using Kernel Virtual Machine, or KVM technology, libvirt management tools, and more to provide hosting and failover suport for virtual machines.

⁠1.1.2.2. Platform as a Service

With the Platform as a Service (PaaS) service model, even more of the resources are provided as a service. The "platform" includes computing resources, a configured operating system, and services and software required by the user's application. The user is then only responsible for their application. For example, a mediawiki deployment would include PHP, a database server, a web server, and mediawiki itself, all preconfigured. The user then only has to take care of administrative work, like defining policies and user roles or populating the wiki with content.

Fedora works at the platform layer, using OpenStack technology to provide a dynamic, scalable platform.

⁠1.1.2.3. Software as a Service

In the Software as a Service (Saas) model, the service provider handles even configuration and management of the application. The user primarily acts as a consumer of the software, often on a subscription basis.

Fedora offers a wide range of software, web applications and development tools that can be leveraged to enable a SaaS endeavor.

⁠1.1.2.4. Understanding Iaas, Paas, and Saas: Email in the Cloud

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Example 1.1. Understanding Iaas, Paas, and Saas: Email in the Cloud

Email communication is vital to modern communication, and a good example of functionality that might be partially or wholly provided as a service. Examine how an organization might handle email in the cloud:

IaaS: The organization deploys mailservers on virtual machines. The maintenance and management of the mailservers and underlying operating system is still their responsibility, but they don't have the overhead of purchasing hardware, dealing with hardware or network failure, or managing storage.

PaaS: The organization manages mailservers that are provided as a service. They are still responsible for management tasks, like configuration of the mailserver and user management, but they don't have to worry about the operating system or mailserver platform.

SaaS: The organization receives all mail services as a service. They are responsible only for providing usage policies or similar information; all support and maintenance are handled by the service provider.