Our mission is to enable secure, multi-tenant, minimal-overhead execution of container and function workloads.

Read more about the Firecracker Charter here.

What is Firecracker?

Firecracker is an open source virtualization technology that is purpose-built for creating and managing secure, multi-tenant container and function-based services that provide serverless operational models. Firecracker runs workloads in lightweight virtual machines, called microVMs, which combine the security and isolation properties provided by hardware virtualization technology with the speed and flexibility of containers.

The main component of Firecracker is a virtual machine monitor (VMM) that uses the Linux Kernel Virtual Machine (KVM) to create and run microVMs. Firecracker has a minimalist design. It excludes unnecessary devices and guest-facing functionality to reduce the memory footprint and attack surface area of each microVM. This improves security, decreases the startup time, and increases hardware utilization. Firecracker currently supports Intel CPUs, with planned AMD and Arm support. Firecracker will also be integrated with popular container runtimes.

Firecracker was developed at Amazon Web Services to accelerate the speed and efficiency of services like AWS Lambda and AWS Fargate. Firecracker is open sourced under Apache version 2.0.

To read more about Firecracker, check out firecracker-microvm.io.

Getting Started

You can build Firecracker on any system that has Docker running (we use a development container). The simple steps to get & build Firecracker are:

git clone https://github.com/firecracker-microvm/firecracker
cd firecracker
tools/devtool build

The Firecracker binary will be placed at build/debug/firecracker. For more information on building, testing, and running Firecracker, go to the quickstart guide.

The overall security of Firecracker microVMs, including the ability to meet the criteria for safe multi-tenant computing, depends on a well configured Linux host operating system. A configuration that we believe meets this bar is included in the production host setup document.

Contributing

Firecracker is already running production workloads within AWS, but it's still Day 1 on the journey guided by our mission. There's a lot more to build and we welcome all contributions.

To contribute to Firecracker, check out the development setup section in the getting started guide and then the Firecracker contribution guidelines.

Releases

New Firecracker versions are released via the GitHub repository releases page, typically every one or two months. A history of changes is recorded in our changelog.

Design

Firecracker's overall architecture is described in the design document.

Features & Capabilities

Firecracker consists of a single micro Virtual Machine Manager process that exposes an API endpoint to the host once started. The API is specified in OpenAPI format.

The API endpoint can be used to:

• Configure the microvm by:
  • Setting the number of vCPUs (the default is 1).
  • Setting the memory size (the default is 128 MiB).
  • Choosing a CPU template (currently, C3 and T2 are available).
• Add one or more network interfaces to the microVM.
• Add one or more read-write or read-only disks to the microVM, each represented by a file-backed block device.
• Trigger a block device re-scan while the guest is running. This enables the guest OS to pick up size changes to the block device's backing file.
• Change the backing file for a block device, before or after the guest boots.
• Configure rate limiters for virtio devices which can limit the bandwidth, operations per second, or both.
• Configure the logging and metric system.
• [BETA] Configure the data tree of the guest-facing metadata service. The service is only available to the guest if this resource is configured.
• [EXPERIMENTAL] Add one or more vsock sockets to the microVM.
• Start the microVM using a given kernel image, root file system, and boot arguments.
• Stop the microVM.

Built-in Capabilities:

• Demand fault paging and CPU oversubscription enabled by default.
• Jailer process for starting Firecracker in production scenarios; applies a cgroup/namespace/seccomp rule isolation barrier and then drops privileges.

Performance

Firecracker's performance characteristics are listed as part of the specification documentation. All specifications are a part of our commitment to supporting container and function workloads in serverless operational models, and are therefore enforced via continuous integration testing.

Policy for Security Disclosures

The security of Firecracker is our top priority. If you suspect you have uncovered a vulnerability, get in touch with us; we will immediately prioritize your disclosure. More details on our process for dealing with this type of event can be found in our security policy document.

FAQ & Contact

Frequently asked questions are collected in our FAQ doc.

The Firecracker community can be contacted in the following ways:

• Chat with us on our Slack workspace. Note: most of the maintainers are on a European time zone.
• Open a GitHub issue in this repository.
• Email the maintainers at [email protected].
• Community email list: coming soon.

When communicating within the Firecracker community, please mind our code of conduct.