In very basic terms cloud computing indicates - cloud computing is a model for enabling convenient, on-demand network access to shared pool of configurable resources such as networks,servers,storage or any kind of applications which can be provisioned to customers rapidly on need basis.
Cloud computing can be deliverd into different model depending on requirement.
It defines basically three models where industries are looking over.
1) Software as a Service(SaaS)
2) Platform as a Service(PaaS)
3) Infrastructure as a Service (IaaS)
Here,to explain briefly
Here, SaaS provider installs, manages and maintains the software. The provider does not necessarily own the physical infrastructure in which the software is running. Regardless, the consumer does not have access to the infrastructure; they can access only the application.
PaaS is basically about sharing a hosted environment to run their applications.But,Here customer can have control over application being used.
Here, PaaS provider manages the cloud infrastructure for the platform, typically a framework for a particular type of application. The consumer’s application cannot access the infrastructure underneath the platform.
IaaS is basically about sharing or providing infrastructure related resources such as storage,networking components or may be middleware too.Major difference here is customer can have control over Operating system, storage, deployed applications, network resources being used.
Here, IaaS provider maintains the storage, database, message queue or other middleware, or the hosting environment for virtual machines. The consumer uses that service as if it were a disk drive, database, message queue, or machine, but they cannot access the infrastructure that hosts it.
With all this,The most important concern is about security of cloud services. I am gonna discuss in great details on this with certain customer use cases.But,Finally to achieve cloud computing "Service Management" really plays a very important role.In addition to that, SLA's, Lifecycle management,Governance plays the key.
I am really not impressed with cloud computing as it's just term used as how IT trend is going on. you must have heard about IaaS long term ago ?