firecracker-node

Type-safe TypeScript SDK for Firecracker microVMs.

Warning

This is an early-stage project and is still under active development. The API may change significantly in future releases. DO NOT use in production environments.

Documentation

Take a look at the docs here

Quickstart

1. Using FirecrackerMicroVMLauncher (Recommended)

The easiest way to launch a microVM. First, configure everything and then launch with a single call.

import { FirecrackerMicroVMLauncher } from "firecracker-node";

async function main() {
  // Create a launcher instance
  // Configure the initial parameters for Firecracker
  const launcher = new FirecrackerMicroVMLauncher({
    apiSock: "/tmp/firecracker.socket",
  });

  // Configure and launch the microVM
  const vm = await launcher
    .setBootSource({
      kernel_image_path: "./vmlinux.bin",
      boot_args: "console=ttyS0 reboot=k panic=1 pci=off",
    })
    .addDrive({
      drive_id: "rootfs",
      path_on_host: "./rootfs.ext4",
      is_root_device: true,
      is_read_only: false,
    })
    .setMachineConfiguration({
      vcpu_count: 2,
      mem_size_mib: 512,
    })
    // Finally, launch the VM
    // This returns a FirecrackerMicroVM instance
    .launch();

  // VM is now running, interact with it
  const info = await vm.getInstanceInfo();
  console.log("VM is running:", info.state);

  // When done, stop the VM
  await vm.stopFirecrackerProcess();
}

main().catch((err) => {
  console.error("Failed to start VM:", err);
});

---

2. Using FirecrackerMicroVM

You can also use FirecrackerMicroVM directly.

There are two ways to use it

1. You spawn the Firecracker process manually and use the API client methods. (Why though?)
2. You can use the built-in method to spawn the Firecracker process.

import { FirecrackerMicroVM, InstanceActions } from "firecracker-node";

async function main() {
  const vm = new FirecrackerMicroVM({
    apiSock: "/tmp/firecracker.socket",
  });

  // Step 1: Spawn the Firecracker process (this starts the API server)
  // If this is not called, subsequent API calls will fail
  // Alternatively, you can start Firecracker manually (systemd or external spawn) and skip this step
  await vm.spawnFirecrackerProcess(true); // true = remove existing socket

  // Step 2: Configure the VM (pre-boot)
  await vm.setBootSource({
    kernel_image_path: "./vmlinux.bin",
    boot_args: "console=ttyS0 reboot=k panic=1 pci=off",
  });

  await vm.createOrUpdateDrive({
    drive_id: "rootfs",
    path_on_host: "./rootfs.ext4",
    is_root_device: true,
    is_read_only: false,
  });

  await vm.setMachineConfiguration({
    vcpu_count: 2,
    mem_size_mib: 512,
  });

  // Step 3: Boot the VM
  await vm.startAction(InstanceActions.InstanceStart);

  // VM is now running
  const info = await vm.getInstanceInfo();
  console.log("VM state:", info.state);

  // When done, stop the process
  await vm.stopFirecrackerProcess();
}

main().catch((err) => {
  console.error("Failed to start VM:", err);
});

---

3. Using FirecrackerAPIClient

Use FirecrackerAPIClient when you're managing the Firecracker process yourself (e.g., via systemd, or manual spawn) and only need to interact with the API.

import { FirecrackerAPIClient, InstanceActions } from "firecracker-node";

async function main() {
  // Connect to an already-running Firecracker socket
  const api = new FirecrackerAPIClient("/tmp/firecracker.socket");

  // Configure boot source
  await api.setBootSource({
    kernel_image_path: "./vmlinux.bin",
    boot_args: "console=ttyS0 reboot=k panic=1 pci=off",
  });

  // Attach rootfs drive
  await api.createOrUpdateDrive({
    drive_id: "rootfs",
    path_on_host: "./rootfs.ext4",
    is_root_device: true,
    is_read_only: false,
  });

  // Start the instance
  await api.startAction(InstanceActions.InstanceStart);

  // Query instance info
  const info = await api.getInstanceInfo();
  console.log("Instance:", info.id, "State:", info.state);
}

main().catch((err) => {
  console.error("Failed to start VM:", err);
});

Contributing

The project is in early stages and needs community suggestions/feedback. Feel free to open issues or submit pull requests!