Tuesday, January 23, 2024

Introducing Firecracker, A micro-VM Platform

Firecracker, an open-source virtualization technology, is purpose-built for the creation and management of secure, multi-tenant container and function-based services. This innovative platform facilitates the deployment of workloads through lightweight virtual machines known as microVMs. These microVMs offer enhanced security and workload isolation compared to traditional VMs, while maintaining the speed and resource efficiency associated with containers. Originally developed at Amazon Web Services to enhance the customer experience of services like AWS Lambda and AWS Fargate, Firecracker leverages the Linux Kernel-based Virtual Machine (KVM) as a virtual machine monitor (VMM).

Distinguished by its minimalist design, Firecracker eliminates unnecessary devices and guest functionality, resulting in a reduced memory footprint and attack surface area for each microVM. This design choice not only enhances security but also decreases startup time and increases hardware utilization. Firecracker is compatible with 64-bit Intel, AMD, and Arm CPUs, supporting hardware virtualization.

Firecracker has gained widespread adoption and integration with various platforms, including appfleet, containerd via firecracker-containerd, Fly.io, Kata Containers, Koyeb, Northflank, OpenNebula, Qovery, UniK, Weave FireKube (via Weave Ignite), webapp.io, and microvm.nix. It is versatile, capable of running Linux and OSv guests. For the latest updates and roadmap information, refer to our official documentation.

How Firecracker MicroVM Works?

Firecracker operates in user space, leveraging the Linux Kernel-based Virtual Machine (KVM) to establish microVMs. The swift startup time and minimal memory footprint of each microVM allow for the efficient packing of thousands onto a single machine. This unique capability enables the encapsulation of every function, container, or container group with a virtual machine barrier. Consequently, workloads from different customers can coexist on the same machine without compromising security or efficiency, positioning Firecracker as a compelling alternative to QEMU—a versatile VMM with a broad feature set accommodating various guest operating systems.

The management of Firecracker is facilitated through a RESTful API, offering control over essential actions such as configuring vCPUs or initiating machine startup. Built-in rate limiters within Firecracker provide granular control over network and storage resources for thousands of microVMs on a shared machine. The API allows the creation and configuration of flexible rate limiters, supporting bursts or specific bandwidth/operations limitations. Additionally, Firecracker offers a metadata service that securely shares configuration information between the host and guest operating system, with setup and configuration achievable through the Firecracker API.

To enhance security, each Firecracker microVM undergoes further isolation through a companion program known as "jailer." This program establishes common Linux user-space security barriers, acting as a secondary defense layer in the event of a compromise to the virtualization barrier.

Firecracker MicroVM vs Docker?

Here are some differences between Firecracker and Docker:


Firecracker provides strong isolation between microVMs to enhance security. Docker containers share the host OS kernel, which can introduce some performance overhead.


Docker's main benefit is a friendly UI over low-level Linux primitives. Ignite offers a similarly familiar UI over Firecracker/KVM, which is also cumbersome to use directly.

Multi-tenant workloads

Firecracker is a virtualization technology that was built to enable multi-tenant workloads on a single server.

Security vulnerabilities

Containers, while offering some level of isolation, share the host operating system, which can lead to potential security vulnerabilities if not properly managed.

Advanced security controls

Docker also provides many advanced security controls.

Multiple applications

Docker containers are considered suitable to run multiple applications over a single OS kernel. 

You can read more about Firecracker MicroVM from their website https://firecracker-microvm.github.io/


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