AWS Firecracker vs Cloud Functions for Firebase: What are the differences?

Introduction
When considering serverless computing options, AWS Firecracker and Cloud Functions for Firebase are two popular choices. Both provide a scalable, cost-effective solution for running code in the cloud. However, there are key differences between the two services that developers must consider before choosing one over the other.

1. Underlying Technology: AWS Firecracker is a lightweight virtual machine monitor (VMM) that uses KVM-based virtualization to create and manage microVMs. On the other hand, Cloud Functions for Firebase is a function as a service (FaaS) offering that runs code in a fully managed environment without the need for managing any infrastructure.

2. Supported Languages: AWS Firecracker supports multiple programming languages, including Rust, C, Go, and more, giving developers flexibility in their choice of coding language. In contrast, Cloud Functions for Firebase primarily supports Node.js, Python, and Java for writing functions. This limitation can impact developers who prefer using other languages for their projects.

3. Integration with Other Services: AWS Firecracker seamlessly integrates with a wide range of AWS services, allowing developers to create complex cloud architectures easily. Cloud Functions for Firebase is tightly integrated with Firebase services, such as Firestore, Realtime Database, and Authentication, enabling developers to build applications quickly using these services.

4. Instance Isolation: AWS Firecracker provides stronger isolation between microVMs, ensuring that workloads are securely separated from each other. Cloud Functions for Firebase runs functions in a shared environment, which may raise concerns about potential security risks associated with multi-tenant infrastructure.

5. Billing Model: AWS Firecracker follows a pay-as-you-go billing model, where users are charged based on the resources consumed by their microVMs. In comparison, Cloud Functions for Firebase charges users based on the number of executions and the compute time required for each function, which can help in cost estimation for specific workloads more accurately.

6. Scalability: While both services are designed to scale automatically based on demand, AWS Firecracker might offer more flexibility in terms of scaling options, thanks to the underlying virtualization technology used. Cloud Functions for Firebase may have limitations on scaling behavior in certain scenarios due to its FaaS nature.

In Summary, AWS Firecracker and Cloud Functions for Firebase differ in underlying technology, language support, integration with other services, instance isolation, billing model, and scalability options, making them suitable for different use cases based on developers' requirements.