Cloud computing the new trend model for enabling workloads, that use resources from a a normally extreme huge resource pool, that is operated by a cloud service provider. These resources include servers, storage, network resources, applications, services or even functions. These can be rapidly deployed, operated and automated with a low effort and the prices are calculated on a minute base. This cloud model is composed of five essential characteristics, three service models, and four deployment models.
Cloud offers are mainly categorized into the following service models:
- Infrastructure as a Service (IaaS): Infrastructure as a Service describes a model in which the cloud provider gives the consumer the possibility to create and configure resources from the computing layer upwards. This includes virtual machines, networks, appliances, and many other infrastructure-related resources:
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- The most popular IaaS resources in Azure contain virtual machines, virtual networks (internal and external), container services and storage.
- Platform as a Service (PaaS): Platform as a Service gives the consumer an environment from the operating system upwards. So, the consumer is not responsible for the underlying IaaS infrastructure. Examples are operating systems, databases, or development frameworks:
- Microsoft Azure contains many PaaS resources such as SQL databases, Azure app services, or cloud services.
- Software as a Service (SaaS): Software as a Service is the model with the lowest levels of control and required management. A SaaS application is reachable from multiple clients and consumers, and the owning consumer doesn't have any control over the backend, except for some application related management tasks.
- Examples of SaaS applications are Office 365, Visual Studio Online, Outlook website, OneDrive, and even the Amazon website itself is a SaaS app with Amazon as its own consumer.
A comparison of service model responsibilities is as follows:
Cloud service models
