What’s Cloud Computing?
Up to now, no generally applicable definition for the term cloud computing has gained acceptance. In books or speeches, definitions are often used that are similar in most situations, but which still change over and over. A definition that’s mostly used among specialists is the definition of this US-American standardization center NIST (National Institute of Standards and Technology). This definition can be used by the ENISA (European Network and Information Security Agency):
“Cloud computing is a model for empowering easy, on-demand network access to a shared pool of configurable computer tools (e.g. networks, servers, storage systems, software and solutions) that may be provisioned quickly and released with minimal management effort or service supplier interaction.”
According to the NIST definition, a cloud support is characterised by the following five attributes:
- On-Demand Self-Service: The tools (e.g. computing power, storage) are provisioned automatically with no interaction with the service provider.
- Broad Network Access: The services are accessible with standard mechanics via the community and aren’t bound to a particular client.
- Resource Pooling: The resources of the supplier are offered in a pool that many users can draw on (multi-tenant version). The users don’t know where the sources are, but might agree the storage place, such as area, state or computer centre by contract.
- Rapid Elasticity: The services can be provided quickly and elastically, in some instances also automatically. From the consumer’s point of view, the resources thus appear to be infinite.
- Measured Services: The utilisation of resources could be quantified and tracked and the cloud users might be provisioned adequately.
This definition reflects the vision of basics of cloud computing, but one ought to abstain from viewing the individual aspects dogmatically. In the event of private clouds, by way of instance, ubiquitous availability may not be sought for whatsoever.
According to the Cloud Security Alliance (CSA), cloud computing has also the following attributes along with the elasticity and the self-service mentioned previously:
- A service-oriented architecture (SOA) is one of the fundamental prerequisites for basics of cloud computing. The cloud services are often offered using a so-called REST-API.
- In a cloud environment, many users share the jointly used resources, meaning the cloud environment has to be multi-client capable.
- Only the tools actually used are compensated for (pay-per-use version), but there might also be flat-rate versions.
Definition of Terms
To ensure that a uniform foundation is available for all future work associated with cloud computing, the BSI has given the following definition for the term “cloud computing”:
Cloud computing is known as supplying, using, and charging IT services dynamically adapted to the requirements, via a network. Here, these solutions are only offered and utilized by means of defined technical logs and interfaces. The assortment of the services provided inside the cloud computing platform covers the whole range of information technology and, among other things, includes infrastructure (e.g. computing power, storage area), platforms and applications.
What Distinguishes a Public Cloud from a Private Cloud?
NIST contrasts between four deployment versions:
- In a private cloud, the cloud infrastructure is only operated for a single organisation. It may be organised and managed by the organisation or a third party and could be found at the gym of the organisation or a third party organisation.
- The term public cloud is used if cloud providers might be used by the general public or a large group, like an entire business, and the services are made accessible by one supplier.
- Within a community cloud, the infrastructure is shared by numerous organisations with similar interests. Such a cloud could be managed by one of those organisations or a third party.
- If several cloudinfrastructures, each of which is independent, are used collectively via standardised interfaces, this is known as a hybrid cloud.
The definitions above, however, don’t cover all versions of cloud supplies, which leads to additional definitions such as “virtual personal cloud” etc..
Which Different Service Models are Offered in Basics Of Cloud Computing?
Generally, a distinction can be made between three different categories of service models:
- Infrastructure for a Service (IaaS)
In the event of IaaS, IT tools like computing power, data storage networks or devices are offered as a service. A cloud client buys these virtualised and highly standardised services and assembles their own services for external or internal use. By way of instance, a cloud user can rent computing power, memory and data storage devices and run an operating system with software of their choice on it.
- Platform as a Service (PaaS)
A PaaS supplier makes an whole infrastructure accessible and, on the stage, offers the client standardised interfaces that are used by providers of the client. By way of instance, the platform can offer multi-client capacity, scalability, access management, database accesses etc. as a service. The client has no access to the underlying layers (operating system, hardware), but can run its own software on the stage, for the growth of which the cloud service provider (CSP) generally provides their own tools.
- Software as a Service (SaaS)
This class contains all offers of software meeting the standards of cloud computing. There are no limitations to the array of offers. Examples include contact information management, financial accounting, word processing or collaboration software.
The expression “as a service” can also be used for numerous additional offers, like for Security as a Service, BP as a Service (Business Process), Storage as a Service, so that often “XaaS” is discussed, i.e. “something for a service”. The majority of these offers can be assigned at least approximately to one of the groups above.
The support models also differ in the client’s influence on the safety of the provided services. In the event of IaaS, the client has full control of the IT system from the operating system upward, since everything is worked within their sphere of responsibility. In the event of PaaS, the client only has control of the software that run on the stage and, in the event of SaaS, the client practically hands over the whole control to the CSP.
What Distinguishes Cloud Computing from Conventional IT Outsourcing?
For outsourcing, work, production or business processes of an organisation are outsourced entirely or partly to outside service providers. This is an established part of business plans today. Generally, traditional IT outsourcing is designed so that the whole infrastructure leased is used exclusively by one client (single-tenant structure) even if outsourcing suppliers normally have several customers. Moreover, outsourcing contracts are ordinarily reasoned over longer contract periods.
Using cloud services is comparable to traditional outsourcing in several respects, but there are also several differences which have to be taken into consideration:
- For economical reasons, many users share a collectively used infrastructure at a cloud.
- Cloud solutions are lively and so scalable in both directions within much shorter periods. Therefore, cloud-based offers can be adapted more quickly to the client’s real needs.
- The cloud providers utilized are usually controlled by way of a web interface from the cloud user themselves. Therefore, the user can automatically tailor the services utilized for their unique needs
- With the technology used for cloud computing, it’s possible to disperse the IT functionality dynamically over several locations which could be dispersed geographically (both at home and overseas).
- The client can easily administrate the services used and their tools through web interfaces or other appropriate interfaces, requiring little interaction with the provider.