If you are part of the cloud development community, you certainly know about “serverless computing”, almost a misnomer. Because it implies there are no servers which is untrue. However the servers are hidden from the developers. This model eliminates operational complexity and increases developer productivity.
We came from monolithic computing to client-server to services to microservices to serverless model. In other words, our systems have slowly “dissolved” from monolithic to function-by-function. Software is developed and deployed as individual functions – a first-class object and cloud runs it for you. These functions are triggered by events which follows certain rules. Functions are written in fixed set of languages, with a fixed set of programming model and cloud-specific syntax and semantics. Cloud-specific services can be invoked to perform complex tasks. So for cloud-native applications, it offers a new option. But the key question is what should you use it for and why.
Amazon’s AWS, as usual, spearheaded this in 2014 with a engine called AWS Lambda. It supports Node, Python, C# and Java. It uses AWS API triggers for many AWS services. IBM offers OpenWhisk as a serverless solution that supports Python, Java, Swift, Node, and Docker. IBM and third parties provide service triggers. The code engine is Apache OpenWhisk. Microsoft provides similar function in its Azure Cloud function. Google cloud function supports Node only and has lots of other limitations.
This model of computing is also called “event-driven” or FaaS (Function as a Service). There is no need to manage provisioning and utilization of resources, nor to worry about availability and fault-tolerance. It relieves the developer (or devops) from managing scale and operations. Therefore, the key marketing slogans are event-driven, continuous scaling, and pay by usage. This is a new form of abstraction that boils down to function as the granular unit.
At the micro-level, serverless seems pretty simple – just develop a procedure and deploy to the cloud. However, there are several implications. It imposes a lot of constraints on developers and brings load of new complexities plus cloud lock-in. You have to pick one of the cloud providers and stay there, not easy to switch. Areas to ponder are cost, complexity, testing, emergent structure, vendor dependence, etc.
Serverless has been getting a lot of attention in last couple of years. We will wait and see the lessons learnt as more developers start deploying it in real-world web applications.