There are generally three cloud service models: SaaS (Software as a Service), PaaS (Platform as a Service) and IaaS (Infrastructure as a Service).

definition

1. Infrastructure as a Service

It refers to the provision of IT infrastructure as a service through the network. In this service model, users do not need to build a data center themselves, but use infrastructure services, including servers, storage and networks, by renting. For example, we can purchase Alibaba Cloud servers directly on the network to use them, instead of building our own computer room, network, storage and other equipment.

2. Platform as a Service

Providers provide platform tools to developers to enable them to develop, run and manage business applications without building and maintaining infrastructure, which is usually required by software development processes 。 Alibaba Cloud and Tencent Cloud also provide PaaS services.

3. SaaS: Software as a Service

Also known as cloud application service, it represents the most commonly used option of enterprises in the cloud market. SaaS uses the Internet to provide users with applications. Most SaaS applications run directly through the browser without client installation 。

contrast

Their services are compared as follows:

Some examples are shown below:

Image understanding

Albert Barron, an IBM software architect, used pizza as a metaphor to explain this problem. David Ng further extended it to make it more accurate and understandable.

If you want to engage in a pizza catering project, there are four options.

1. Scheme 1: do all by yourself

Produce your own pizza from beginning to end (prepare kitchen, oven, gas, shop, materials...)

2. Scheme II: IaaS

Use the kitchen, oven, gas and other infrastructure provided by the provider, and then you can make and bake your pizza.

3. Scheme III: PaaS

In addition to infrastructure and providers, they also provide more materials (pizza crust, cooking wine, chicken...). What you need to do is to design the taste of pizza (chicken pizza, seafood pizza...). Others provide platform services to realize your design.

4. Scheme IV: SaaS

The supplier makes pizza directly, and the finished product is in hand. All you have to do is sell it. Of course, you can repack it and print your logo.

The above four schemes can be summarized into the following figure.

Reference link:

• SaaS, PaaS and IaaS explained in one graphic, by David Ng

• When to use SaaS, PaaS, and IaaS, by Eamonn Colman

• //www.ruanyifeng.com/blog/2017/07/iaas-paas-saas.html