What is FaaS? Function as a Service Explained

Note: Pricing and product information are correct as of August 7, 2024, and subject to change

Serverless computing allows developers to build and run applications without having to manage cloud infrastructure. There are still servers in serverless, but they are abstracted away from app development. Using a serverless model, a cloud provider handles the routine work of provisioning, maintaining, and scaling the server infrastructure, and developers can focus on code for deployment.

Function as a Service (FaaS) and serverless are often referred to synonymously, but they actually have two specific definitions. While serverless refers to any category where the server is fully abstracted from the end-user, FaaS is a subset of serverless computing that’s focused on event-driven triggers where code runs in response to events or requests. If there is no event-driven request, the server shuts down, making its resources available for other requests. Once deployed, FaaS responds to demand and automatically scales up and down as needed. Typically, when a serverless function is sitting idle, it doesn’t cost anything, saving money in many situations. Read on to learn about FaaS, its benefits, the relationship between IaaS, PaaS, and FaaS, and the factors to consider when choosing the right FaaS for your business.

What is FaaS?

FaaS is a cloud computing service model where developers can run and manage application functions without the need to provision or maintain any underlying infrastructure, such as servers or virtual machines. In a FaaS environment, the cloud provider handles all server-side logic and infrastructure management, allowing developers to focus solely on writing and deploying their code.

How FaaS works

Early applications were typically written using a monolithic architecture. This meant that the application was structured as a single execution that had to be triggered all at once. Over time, developers have increasingly shifted to using microservices. Microservices are a collection of modules that are independently deployable. Because they can be worked on individually, they are easier to test and maintain.

A function is essentially a microservice that can only perform one action in response to an event. With FaaS, the provider will spin up a server when a function is triggered. It will execute the function, then shut down the server. Serverless offerings are only active when the function is being used, allowing the same computing resources to be allocated elsewhere when the server is shut down.

Developers using FaaS have access to a platform that allows them to execute the code for their applications. Simplicity is the strong suit of FaaS. In order to use FaaS to the best of its ability, developers must ensure that each function only performs one action. The scope of the function should be limited and efficient. Using too many libraries or asking one function to call another function will quickly slow down the application and increase costs.

Benefits of FaaS

FaaS offers significant advantages for developers and organizations that are building in the cloud. It abstracts away the underlying infrastructure, allowing developers to focus on writing and deploying their application code. This streamlined approach reduces operational overhead, enables faster time to market, and allows teams to scale their applications effortlessly based on demand.

Scalability

One of FaaS’s key benefits is its inherent scalability. With FaaS, you don’t have to worry about provisioning and managing servers to handle your application’s workload fluctuations. The cloud provider automatically scales your serverless functions up or down based on incoming traffic and demand, ensuring your application can handle increased usage without your manual intervention. FaaS is an excellent choice for applications with unpredictable or spiky traffic patterns.

For example, if an e-commerce website experiences a sudden surge in traffic during a major sale event, the FaaS platform will automatically scale the checkout and order processing functions to handle the increased load without a dedicated resource having to provision additional servers or worry about capacity planning.

Cost optimization

FaaS platforms charge you only for the actual compute time used by your functions rather than for the entire time a server is running. This “pay-as-you-go” model can lead to significant cost savings, especially for applications with intermittent usage or short-lived tasks. You don’t have to worry about paying for idle server capacity; you can scale up and down as needed without incurring additional infrastructure costs.

Consider a cloud photo-sharing application where serverless functions process user-uploaded images. In this workflow, the billing is processed only for the actual time it takes to execute that function, rather than having to pay for a constantly running server. This can result in significant cost savings and can help increase your cloud ROI.

Reduced operational overhead

With FaaS, the cloud provider handles all the infrastructure management tasks, such as provisioning servers, applying security patches, and scaling resources. This frees you from the burden of managing and maintaining the underlying infrastructure, allowing you to focus your time and resources on writing and deploying your application code. This can optimize cloud costs, reduce operational complexity, and improve developer productivity.

When using a FaaS platform, you can simply upload your code and define the event triggers, and the platform will run and scale your function as needed. This can simplify the deployment process and allow developers to focus on cloud capacity planning strategies and building features rather than managing servers.

The relationship between IaaS, PaaS, and FaaS

Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and FaaS are all cloud computing offerings. The difference between them is the level of abstraction they provide between the user and the infrastructure.

IaaS offers the lowest level of abstraction. With IaaS, users have complete control over their infrastructure and the software and tools associated with their tech, but they don’t have to control or manage the physical infrastructure, like bare metal servers or data centers. IaaS gives developers the opportunity to choose the layers of abstraction they want. They can choose to manage everything, or they can layer in features such as load balancers or even managed services, including Managed Kubernetes or Managed Databases, to make maintaining their application easier.

PaaS adds another layer of abstraction for the end-user. With PaaS, users no longer have to manage the operating system, runtime, or other infrastructural components of their application but will still have granular control over underlying application and infrastructure configurations. PaaS provides a fully managed infrastructure solution for developers looking to launch applications quickly. When developers choose to use PaaS, they can focus on their development work and let the provider manage backend services and system administration.

Of the three, FaaS offers the most abstraction for the user and the most specific functionality. With FaaS, developers have access to a platform that executes application logic on demand, and all of the application resources and other infrastructural components are managed by the service provider.

FaaS vs. PaaS

While FaaS and PaaS offerings initially seem quite similar, there are key differences to consider when deciding which is right for you.

• Configuration. Because of its straightforward use case and completely managed solutions, FaaS offers extremely low provisioning time. Even though PaaS offers more abstraction than other cloud computing models, it still requires some configuration. This can be a benefit or a downside, depending on the level of control you desire.

• Operations. FaaS technologies spin entire applications up and down for individual requests. While PaaS can scale up and down as needed automatically, resources are generally always running. This feature of FaaS can affect latency, pricing, and the ability to handle complex requests.

• Scalability. PaaS does scale up and down as needed, but it requires some configuration from the developer. FaaS doesn’t require any capacity planning. It scales readily and easily as required.

• Pricing. PaaS has different pricing models depending on your provider but is often more costly than FaaS if you run a low workload. FaaS allows developers to pay per function invocation, saving time if event triggers are few. PaaS may be the better option for consistent or high workloads in terms of pricing.

Factors to consider when choosing FaaS

FaaS can be used in a variety of ways, from web apps, data processing, and online chatbots to backend functions and more. Before committing to a FaaS provider, consider the following:

• Workloads. Choose FaaS for simple and repetitive functions without consistent workloads or high volumes of requests. Because FaaS is typically priced per function execution, costs for high usage could potentially be higher than using a PaaS offering. If your workload is relatively small, FaaS is a great choice for simplifying provisioning and saving money.

• Control. FaaS is one of the most abstracted cloud offerings. Consider the amount of insight and control you prefer over your configurations and infrastructure. If you want a bit more control than FaaS offers while maintaining similar ease of use, try a PaaS solution. Teams that want complete control over their production environment and the design and behavior of their infrastructure should consider using an IaaS solution.

• Vendor lock-in. It can be challenging to migrate applications built through providers. Using open-source cloud solutions makes it easier to migrate computing operations from one provider to another.

• Integration capabilities. Evaluate the FaaS provider’s integration capabilities with your existing tools, systems, and workflows. Seamless integration can improve developer productivity and simplify your overall cloud operations.

• Pricing model. Understand the FaaS provider’s pricing structure, including any free tiers, usage-based pricing, pay-as-you-go, and potential cost fluctuations during periods of high demand. Ensure the pricing model aligns with your expected usage patterns and budgetary requirements.

• Ecosystem and community support. Consider the strength of the FaaS provider’s ecosystem, including available language runtimes, third-party integrations, and overall community support. A strong ecosystem can simplify development, ease deployments, and allow your team to access a wealth of resources and expertise.

Discover the simplicity of serverless with DigitalOcean Functions

DigitalOcean Functions integrates with the cloud ecosystem, allowing you to rapidly spin up and scale your serverless workloads without the hassle of provisioning and managing servers.

You can spend more time building cloud applications and less time managing them. With DigitalOcean Functions, you can:

• Develop and launch modern apps quickly without provisioning or managing servers, and build or extend your apps easily without learning new frameworks or languages.

• Invoke functions (snippets of code) in response to web events, and you will only be charged when your resources are active. This transparent and simple “pay-as-you-go” pricing model saves you money.

• Scale up or down instantly and automatically based on demand without needing pre-provisioned resources.

• Comprehensive logging and monitoring capabilities make it easy to debug your serverless functions.

Take your development to new heights with DigitalOcean Functions!