Function as a Service (FaaS) and Container as a Service (CaaS) are two deployment solutions for cloud-native applications. Knowing what distinguishes these two deployment strategies can help when deciding how to build and deploy your web apps. We covered their unique advantages and challenges in our previous blog post Cloud Computing and Serverless Architectures: What are FaaS and CaaS?.
This time we are diving into the details about the differences in the managed responsibilities between developers and the cloud service providers of these solutions. Additionally, we're going to look at their ideal use cases all in order to best understand when to use these solutions.
We created this table to display the difference in managed responsibilities between cloud service providers and the developers who use them. As this table demonstrates, the differences in managed responsibilities arise at the container and runtime levels.
As the name implies, containers are used in CaaS solutions. The reason containers are optional for FaaS solutions is because it is the responsibility of the cloud service provider to determine how to run your functions. Some cloud service providers use containers to deploy their FaaS offerings while others do not.
The same logic follows for runtimes. Runtimes are the software that manages the complete lifecycle of a container. With CaaS, the container and runtime are the developer's responsibilities whereas they are the cloud service provider's responsibility with FaaS.
We prepared a table to compare the FaaS and CaaS options on these various key points:
|Portability||Poor standardization, implementation is mostly vendor-specific||Containers are a standardized unit of software and easy to move between providers|
|Lift and shift||Not possible, existing applications need to be adapted if not rewritten||Yes, existing applications are easy to containerize if not already containerized|
|Granularity||Designed to breakdown your application into really small deployment units aka functions||Component/service level deployment by design but can also deploy specialized functions|
|Runtime||Managed by cloud service provider||Managed by developer|
|Flexibility||Limited control of the runtime||High flexibility|
|Frameworks||Specialized Frameworks (Jets, Zappa)||Standard frameworks (Rails, Django, Next.js, Vue.js, Symfony...)|
|Use cases||Specialized functions, asynchronous processing, event-driven processing||Full web apps, Micro-services, data-processing|
|Challenges||Dependency management, amplified challenge of managing multiple micro-services||Requires an understanding of containerization|
|When||Best for greenfield development or spin-off parts of your core application||Efficient to host all your core services|
Koyeb is a developer-friendly serverless platform to deploy container-based or function-based applications globally that lets you enjoy fast startup times and minimal overhead for each application you deploy.
The Koyeb serverless platform enables native and effortless scalability all while combining the flexibility of PaaS with the performance and security of MicroVMs. Get the security and isolation features required for data-sensitive applications without compromising on speed, security, and performance.
Koyeb users can connect their GitHub accounts to Koyeb to streamline and bolster the development of their applications. See the benefits of going serverless, get started with a free account today!
Here are some useful resources to get you started:
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