Sometimes all you need is a single function. That’s the idea behind serverless computing, where individual functions spin up on demand, perform a minimal piece of work (serve as an API endpoint, return static content, and so on), and shut down. It’s cheap, it uses minimal resources, and it has little management overhead.
Most of what we currently identify as serverless computing kicked off with AWS Lambda, later joined by similar services on Microsoft Azure, Google Cloud Platform, and IBM Bluemix. But there’s a healthy complement of open source serverless architectures available—not only facilitators for the serverless frameworks on a particular cloud, but full-blown methods to deploy serverless frameworks on the cloud or hardware of your choosing.