Serverless Vs Microservices Architecture - A Deep Dive

Companies need to be thinking long-term before even starting a software development project. These needs are solved at the level of architecture: business owners want to assure agility, scalability, and performance.

The top contenders for scalable solutions are serverless and microservices. Both architectures prioritize security but approach it in their own ways. Let’s take a look at how businesses can benefit from the adoption of serverless architecture vs microservices, examine their differences, advantages, and use cases.

What Is the Difference Between Serverless and Microservices Models?

The microservice architecture is defined as a decentralized application that was divided into a range of smaller modules, also known as services. Each of them is responsible for the perfect execution of an individual function. Microservices are narrowly specialized — they perform one task, but impeccably.

The key difference between microservices and serverless

Both architectures have their own approaches to solving problems. Microservices offer long-term solutions. Each service is able to run 24/7 on a continuous basis. It’s a great permanent solution for teams with scaling in mind.

Functions of serverless apps, on the other hand, are oriented towards code efficiency. Functions aren’t long-term, like microservices. They only start running when there’s a specific condition or input. Serverless architecture is event-driven, meaning if there’s no trigger, the function won’t work.

It’s an efficient development approach — the application doesn’t consume more CPU than needed, and teams get to cut costs on computing and storage space.

These fundamental differences aside, there are other aspects in which two architectures are different. Let’s zoom in on several main factors of choosing between serverless computing vs microservices.

Functions

Functions are short-term and run only when there’s a condition that requires it. They are smaller and narrower. A function is dedicated to one task while a microservice can handle several related processes simultaneously. A single microservice equals several functions.

Different approach to IT operations

Microservices rely on the development of team resources. An in-house or outsourcing team performs monitoring, deployment, support, and maintenance. The responsibility for the support of the architecture, its computing, and safety is fully handled by the team.

Serverless architecture, on the other hand, relies on the third-party vendor. The company doesn’t have to develop, secure, and maintain its server space. The Cloud vendor handles all internal operations. This approach allows reducing project costs, bypassing hiring, and onboarding expenses as well as storage costs and hardware investments.

Cost

Developing microservices is more expensive in the first stages. You need several teams to handle the project and setting up the relations between the components requires time and thorough planning.

Also, because microservices rely on in-house resources and support, their development and maintenance result in being more expensive. There are advantages to this approach, though. The company doesn’t depend on third-party plans and doesn’t risk a potential vendor lock-in.

The main competitive advantage of serverless architecture is the possibility to reduce costs. When companies use serverless architecture, they benefit from sharing resources. Third-party vendors distribute servers among many clients, which is why they can allow cheaper subscriptions. Also, you are saving on HR expenses — there’s no need to hire server and hardware specialists.

Runtime

Serverless functions have a limited runtime. Every provider has its own limitations on how much a given function can run. On AWS Lambda, for instance, a function can work for 15 minutes. This is because functions, by their design, are short-term processes that shouldn’t take up a lot of RAM.

Microservices are not limited by vendors’ requirements to runtime, storage space, and RAM. This is why they are a better fit for complex long-term operations that involve storing and manipulating huge amounts of data.

Serverless Functions vs Microservices

Both architectures have a certain degree of granularity — the functionality is isolated and needs to be managed separately. It’s convenient when it comes to fixing bugs, testing, and releasing updates, but in a day-to-day development process, having to switch between multiple components all the time can be a struggle.

You need to take into account the limitation of serverless functions vs microservices before making a choice.

Faster and more responsive. You can finetune the tiniest operations in your system, perfecting the functionality to a high degree. However, all these settings will be short-lived.

Specific to a particular provider. You need to learn the conditions of your chosen vendor before making a choice between serverless and microservices. On paper, serverless might fit your project better, but when it comes to an actual working environment, Cloud vendors might not offer what you are looking for.

Cost-efficiency and shortened time to market. Developers can build functions with ready templates and reuse the codebase for new features.

Microservices are suited for a mature development approach. It’s a great architecture for large platforms with rich functionality and many components. Netflix, PayPal, LinkedIn — all these companies chose to decentralize their architecture as soon as the infrastructure was getting too big.

So, if you are planning to scale your solution, focus on personalization features, and cover many niches simultaneously, definitely consider microservices.

Combining serverless and microservices

Today development teams don’t necessarily need to choose between a serverless and microservice architecture. Cloud providers (Google, Amazon, Microsoft) picked up on their growing demand on both approaches and found ways to bridge the gap between them.

Microservices can be developed as a set of event-driven functions and stored on the third-party vendor’s infrastructure.

Here’s how development teams can approach building a combined system without choosing between microservices architecture vs serverless architecture.

• To be serverless, microservices should be event-triggered. Microservices should respond to particular conditions and user actions in order to work as a function.
• Developers can increase the viability of serverless functions by integrating them together. It can be done with Logic Apps (Microsoft) or Step Functions (Amazon). These tools allow assigning triggers to microservices and combine several functions into a service.
• Transfer to the Cloud is crucial. Serverless development heavily relies on Cloud storage and computing. If you are considering implementing certain principles from serverless architecture, switching to a Cloud infrastructure should be your first move.

How Does Serverless Work?

Serverless is an architecture where companies are using third-party vendors’ resources to host their application functions. All features and logic of the application are broken into Functions — small components that perform small tasks over a limited period of time.

Each function can be activated repeatedly as a response to a trigger.

Serverless architecture allows building responsive applications that quickly process user requests and consume little RAM. It’s lightweight, fast, and cost-efficient. This is why serverless architecture is a top choice for realtime apps, assistants, MVPs, etc.

Let’s take a look at the key stages of building a serverless architecture. We’ll examine the main terms and their relationships with each other — so you have a step-by-step idea of how the architecture works.

• Functions: developers write code that will perform a particular task within the application. It’s usually a simple, short-term process. One function cannot perform many actions.
• Event: developers assign events for each function. If the planned conditions are met, the function will be activated. A classical event example is an HTTP request.
• Trigger: an event triggers the function. It happens when a user clicks a button, touches a screen in a defined point, or presses a particular key.
• Execution: the function starts running.
• Output: users receive updates on the client-side of the application in the form of a particular output.

So, in order to build a serverless app, you need to break your app’s functionality down to small components, called functions. The next step is defining trigger events for each of them — what users should do or not do in order for a function to work.

Developers define which outputs are desired and attach them to the component. Many functions can run simultaneously and respond to different interactions. In that case, it’s important to define how they relate to each other.

Advantages of Using Serverless Architecture

Serverless applications are divided into two parts. The first one is the backend, and it’s handled entirely by the Cloud provider. Developers don’t have to worry about internal logic or integrations with hardware.

Another segment is Function as a Service — the client-side functionality. It’s made up of event-triggered functions, and it’s a visible part of the application. Users are able to interact with FaaS and applications respond to their actions by running a particular component.

This structure allows developers to optimize the creation process and improve the performance of the end product — let’s take a deeper look at how that’s accomplished.

Easy deployment: a development team doesn’t have to worry about the backend functionality. The only task is to write the functionality code and release it on the server. The operational processes are handled by a vendor.

Cost-efficiency: human resources, hardware, internal logic — all these aspects of software development are handled by a vendor. The company doesn’t have to pay for internal processes.

Improved salability: if your product suddenly attracts more users than anticipated, you can increase the storage space and computing power at any given moment. When the workload is back to normal, your consumption will also return to its previous limits. This is an advantage of a pay-per-use system, you get access to potentially huge computing resources but pay only for what’s needed at the moment.

Increased flexibility: you can quickly release new features by adding new functions and triggers. You can even use templates and reuse existing codebase to improve the development speed. Most serverless architectures can be integrated with code repositories, too.

Decreased latency: servers of Cloud vendors are located all over the world. Requests from users don’t have to travel huge distances, because the provider will automatically pick the server that’s the closest to a user.

With serverless architecture, you get access to huge computing resources that belong to large technology enterprises. Acquiring large server spaces on your own would be a risky investment, but with a serverless approach, you get access to infrastructure that is already ready to run.

How Do Microservices Work?

In a nutshell, microservices are independent components that run a particular functionality. Each service works standalone and is responsible for a specific process. Practically, this concept is usually executed with containers.

Often, a microservice is developed in a container with code libraries and templates. Each container provides a running environment for the service and contains everything that a component needs to function. Docker is the most popular choice for container development.

To build a microservice application, the team goes through the following stages.

• Decomposition: all the features of the app are broken down into smaller chunks. A team is focused on presenting the entire functionality in a decentralized model.
• Design: after you know which services you’ll be dealing with, it’s time to figure out the relationships between each service. You also need to set up the hierarchy — which microservices will depend on others?
• Development: when the map of microservices is ready and the team understands how components will make up a single system, developers start building services. This is accomplished in smaller teams, where each unit (2-5 developers) is responsible for a single service.
• Deployment: microservices can be deployed in containers, separate VMs, or as FaaS in a serverless infrastructure.

Advantages of Using Microservices Architecture

Microservices provide an answer to many issues created by monoliths. They solve the lack of flexibility, giving developers a way to improve features one at a time. Such an architecture is scalable by design and easy to control.

Main characteristics of microservices

Made up by components. Each system, built with microservice architecture, can be broken down into dozens of smaller services. Each of these components can be developed, tested, and deployed independently. Microservices are isolated — developers can change one service without affecting the entire architecture.

Decentralized. Each component has a separate database. Even if one microservice has a security issue, it will not affect all the stored data. Moreover, developers can use different protection methods for various services, building the strongest protection for the ones that handle the most sensitive information.

Low risks. When one service fails, it can be substituted by another. Developers can change connections between servers and distribute the functionality of a failed component between functioning ones. Most importantly, unlike monoliths, microservices rarely go out of order at the same time.

Scalability. Many businesses decide to switch to microservices when it’s time to scale their product. This is what Netflix did: the team chose to restructure their platform, break it into microservices, and rewrite the backend with Node.js. Was it an ambitious move? Sure, but it saved more than $1 billion in the long run.

Also, microservices are perfectly in line with modern management methodologies like Agile and DevOps, where small trams prefer to take responsibility for the entire task — in this case, for a single service.

Working with Microservices and Serverless Architecture at TechMagic

Both microservices and serverless architecture follow the same structural principles. They oppose the traditional, monolithic development approaches, prioritizing scalability, and flexibility instead. Microservices focus on long-term stability — each service can work as an app on its own and run long-term. Functions are set up as a response to a trigger and are short-lived by its nature.

To choose between a serverless architecture and microservices, companies need to analyze their product’s scope and priorities. If cost-efficiency and shorted time to market is a goal, serverless architecture is a go-to choice.

If you are building a large platform with constant scaling in mind, microservices will provide you a long-term solution. If you’d like the benefits of both, you can combine microservices and serverless using Cloud infrastructure.

Previously published on https://blog.techmagic.co/serverless-vs-microservices-which-architecture-to-choose/.

About the author - Shamim is a Tech Writer and contributes with his writings on DZone, Javelynn, FlyBHP, Hackernoon, Dev.to and Medium.