Cloud computing is a model for enabling universal, convenient, on-demand network access to a shared pool of configurable computing resources (for example: networks, servers, storage, applications, and services). These resources can be rapidly provisioned and released with minimal management effort or service provider interaction. Below figure shows an overview of cloud computing.
Cloud computing provides computation, software, data access, and storage services that do not require user knowledge of the physical location and configuration of the system that delivers the services.
Private and public cloud
A cloud can be private or public. A public cloud sells services to anyone on the Internet. A private cloud is a proprietary network or a data center that supplies hosted services to a limited number of people. When a service provider uses public cloud resources to create their private cloud, the result is called a virtual private cloud. Whether private or public, the goal of cloud computing is to provide easy, scalable access to computing resources and IT services.
Cloud computing components
We describe the cloud computing components, or layers, in our model.
A cloud has four basic components
1. Cloud Services
2. Cloud Infrastructure
3. Cloud Platform
4. SAN + Storage
Cloud Services
This layer is the service that is delivered to the client, it can be an application, a desktop, a server, or disk storage space. The client does not need to know where or how their service is running, they just use it.
Cloud Infrastructure
This layer can be difficult to visualize depending on the final delivered service. If the final service is a chat application, the cloud infrastructure is the servers on which the chat application is running. In the other case, if the final service is a virtualized server, the cloud infrastructure is all the other servers that are required to provide “a server” as a service to the client. Examples of these types of servers include: domain name server (DNS), security services, and management.
Cloud Platform
This layer consists of the selected platform to build the cloud. There are many vendors like IBM Smart Business Storage Cloud, VMware vSphere, Microsoft Hyper V, and Citrix Xen Server, which are well known cloud solutions in the market.
SAN + Storage
This layer is where information flows and lives. Without it, nothing can happen. Depending on the cloud design, the storage can be any of the previously presented solutions. Examples include: Direct-attached storage (DAS), network-attached storage (NAS), Internet Small Computer System Interface (iSCSI), storage area network (SAN), or Fibre Channel over Ethernet (FCoE). For the purpose of this book, we describe Fibre Channel or FCoE for networking and compatible storage devices.