Virtualization is repeatedly in this website mentioned as the basic technology for cloud computing, but it is not a prerequisite for cloud computing. Distributing hardware resources to virtual machines is one of several possible strategies to achieve multi-tenancy. With software as a service, in particular, large players show that virtualization is not a prerequisite for the provision of cloud services. SaaS, particularly not always about “cloud”, it is more about the licensing structure. Adobe Photoshop, MS Office online is more about the licensing structure.
The use of virtual instances and container technologies is particularly common with Infrastructure as a Service (IaaS). They allow legacy applications to be migrated to the cloud without having to be modified. Cloud computing leverages storage virtualization for creating a layer of abstraction. Storage virtualization enables providers to offer storage as a commodity.
The providers of virtualization software, in particular, beating the drums for a long time for the private cloud. What does it mean? A simple and often used definition for the private cloud is that it transfers the concepts and technologies of the public cloud to the company’s internal data centres. The main reasons for setting up a private cloud are security concerns or strict legal regulations for certain industries that do not allow data to be given away.
When companies set up private clouds, the IT department positions itself towards internal users like a service provider towards its external customers. Specialist departments should then themselves be able to book the resources they need via a self-service portal and use them immediately. Guaranteeing service levels and consumption-based billing are also part of the private cloud.
Erich Clementi (IBM) once said :
Google is not virtualized, and virtualization is not sufficient to qualify as a cloud — it’s a better use of the physical infrastructure, but the real bang comes from modelling out the whole data centre and taking energy, labour, software and hardware and acting on all those levels.