Architecture & DesignServerless Functions versus Microservices

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Serverless Functions vs Microservices

Microservices and Serverless architectures are two of the buzzword-heavy technologies that have become extremely popular in recent times. Although there are similarities between a microservice and a Serverless application, there are also many differences between the two. Today, we will look at how these two compare and contrast against each other and learn some of the benefits of each type.

What is Microservices Architecture?

Microservices are an architectural paradigm for building flexible, extensible, and independently deployable services. Microservices architecture is a conglomeration of loosely connected services built, tested, and deployed independently. It is a term used to refer to a collection of independently deployable services that operate in their environments and interact with one another via well-defined interfaces.

Benefits of Microservices Architecture

Another way to look at a microservice or the microservices architecture is to say that they are a way to structure an application as a group or collection of services that have the following features:

  • Easy to maintain and test
  • Fewer errors and easy debugging
  • Loosely coupled and independently deployable
  • Organized with a business’ capabilities in mind
  • Owned by small teams traditionally
  • Allow for rapid (and reliable) delivery of big and complicated applications and software.

Read: An Introduction to Microservices.

Why Should Developers use Microservices Architecture?

Microservices architecture provides many benefits for developers. In the microservices architecture, each service typically runs in its own container. This enables us to develop, deploy, manage and scale these services independent of one another. Unlike a monolithic application, you need not scale the entire application. Instead, you can scale only specific or selective services as needed. It is also easy to add new features or update existing features in an application that takes advantage of the microservices architecture.

Applications that take advantage of microservices architecture are resilient. For example, failure of one of these services will not bring the whole application down since each microservice is developed separately. Another advantage of microservices architecture is that it enables you to take advantage of container technologies like Docker, Kubernetes, and so forth.

What is Serverless Computing?

Serverless computing is an execution paradigm for cloud computing in which developers may develop and deploy code without comprehending how the underlying infrastructure works. Serverless computing is also known by the name Function-as-a-Service (FaaS), since developers assemble the source code inside the building blocks or functions. Serverless computing – or Serverless architecture – is supported by AWS Lamda, Apache OpenWhisk, Azure Functions, IBM Bluemix, OpenWhisk, and Google Cloud Foundation.

Are There Servers in Serverless Computing?

I should point out here that the term “Serverless” is a misnomer. Serverless computing does not, in any way, mean that there is no server. There still is a server, but you don’t need to buy or manage it. In a typical Serverless computing model, the server management capabilities and capacity planning decisions are handled by the infrastructure and are abstracted from the developer – hence the name “Serverless” computing. In a Serverless computing model, the developers need not be worried about purchasing, provisioning, or managing the backend servers.

Serverless architecture depends mainly on two concepts, namely: Function-as-a-Service and Backend-as-a-Service. While BaaS enables you to build applications where the client application talks to the database directly, FaaS provides the facility to develop and deploy a piece of code that can be executed on a specific event.

Serverless Computing: Benefits and Downsides

Serverless computing is an extension of microservices. It is becoming popular primarily because of its support for event-based architecture, reduced time to setup, deploy, and operate, and reduced operational costs. In a Serverless architecture, you need not bother with how the underlying infrastructure works, how the infrastructure can be scaled, and so on.

Serverless functions also enable your application to be elastic; these functions can automatically scale up when needed to accommodate concurrent users and then scale down when the traffic decreases. Another benefit of using Serverless computing is that you need not worry about managing the servers or provisioning the infrastructure – this gets taken care of by the cloud service provider you are using.

While there are benefits aplenty for Serverless computing, there are a few drawbacks too. Serverless computing is not a good choice where speed is paramount, such as an eCommerce application. Due to the event-driven nature of Serverless computing, it is also not a good choice for long-running apps. That said, it would be difficult to build complex apps using Serverless architecture, as you would have to manage a lot of dependencies and coordination between the Serverless functions.

Read: Introduction to Azure Serverless.

Comparing Microservices and Serverless Computing

Serverless computing is similar to microservices in which a large monolith is broken into small pieces that can be independently developed, deployed, and managed. While both microservices and Serverless architectures lower operational costs and reduce time to market, there are subtle differences between the two.

Serverless applications differ from traditional architectures in that these applications run in a stateless environment. These types of applications are computing containers, to be more precise, and are event-driven and ephemeral in nature. Serverless computing is a technology that replaces the long-running virtual machines with computation power that executes only on demand and then disappears as soon as the execution of the compute function is over. As a result, you just need to pay for the short span of time the server took to execute the function.

Contrary to a Serverless function, a microservice may perform more than one function. In other words, depending on how it has been architected, a microservice may be equal to one or more Serverless functions.

You can deploy a microservice as part of a Serverless architecture or host it in containers. On the other hand, Serverless microservices are deployed in the server vendor’s infrastructure and are executed only when they are needed. Once execution is over, the server that runs the code is decommissioned.

How to Choose Between Microservices and Serverless Architecture

Although a Serverless application shares many of the same benefits as a microservice, there are differences aplenty. According to the rule of thumb, select Serverless computing when you need automated scalability as well as reduced runtime costs. Serverless computing is a good choice for applications that execute only for short periods of time and have high traffic.

Because some applications thrive on Serverless and microservices, choosing between the two approaches is not always necessary. It is possible to combine the benefits and limitations of microservices and Serverless technologies by using them together. Depending on your preferences, microservices may be deployed as part of a Serverless architecture or hosted in containers. However, you can deploy Serverless applications only inside the infrastructure provided by the vendor you’ve chosen.

The Future of Microservices and Serverless Computing

The quest for greater agility and scalability has opened the doors to the advent of technologies like microservices architecture, Serverless computing, and so forth. While both microservices and Serverless computing have their pros and cons, the million-dollar question now is, what’s the future? Is it microservices architecture or Serverless architecture?

Adoption of either microservices or Serverless architectures is not only a technical change but also requires a change in mindset. Despite the fact that Serverless is not in the mainstream, it will soon be there. Gartner predicts that Serverless computing will boom along with machine learning and IoT in the next few years. With Serverless computing gaining traction day by day, it seems to me that Serverless microservices (i.e., a microservice deployed within a Serverless architecture) seem to be the future.

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