Understanding Serverless Computing

Normally, to release a cloud solution, application developer must place their code on a cloud-based server (physical or virtual) that resides in a PaaS solution. As you know, the PaaS solution consists of a server, operating system, and option software such as a database and specific programming-language support.

While a PaaS solution works well for most applications, there are times when the processing the developer must perform is simple in nature, such as a RESTful web service, as discussed in Chapter 11, “Service-Oriented Architecture,” which does not require a full PaaS solution.

For such cases, many PaaS providers offer a function-based solution that lets developers load their application into a smaller protected processing space. Amazon, for example, refers to such standalone pieces of code as a Lambda. Because such processing does not require a separate server, it is known as serverless processing. FIGURE 18-8 illustrates the concept of a Lambda.