firecracker.yaml

swagger: "2.0"
info:
  title: Firecracker API
  description: RESTful public-facing API.
               The API is accessible through HTTP calls on specific URLs
               carrying JSON modeled data.
               The transport medium is a Unix Domain Socket.
  version: 0.20.0
  termsOfService: ""
  contact:
    email: "compute-capsule@amazon.com"
  license:
    name: "Apache 2.0"
    url: "http://www.apache.org/licenses/LICENSE-2.0.html"

host: "localhost"
basePath: "/"

schemes:
  - http
consumes:
  - application/json
produces:
  - application/json

paths:
  /:
    get:
      summary: Returns general information about an instance.
      operationId: describeInstance
      responses:
        200:
          description: The instance information
          schema:
            $ref: "#/definitions/InstanceInfo"
        default:
          description: Internal Server Error
          schema:
            $ref: "#/definitions/Error"

  /actions:
    put:
      summary: Creates a synchronous action.
      operationId: createSyncAction
      parameters:
      - name: info
        in: body
        required: true
        schema:
          $ref: "#/definitions/InstanceActionInfo"
      responses:
        204:
          description: The update was successful
        400:
          description: The action cannot be executed due to bad input
          schema:
            $ref: "#/definitions/Error"
        default:
          description: Internal Server Error
          schema:
            $ref: "#/definitions/Error"

  /boot-source:
    put:
      summary: Creates or updates the boot source.
      description:
        Creates new boot source if one does not already exist, otherwise updates it.
        Will fail if update is not possible.
        Note that the only currently supported boot source is LocalImage.
      operationId: putGuestBootSource
      parameters:
      - name: body
        in: body
        description: Guest boot source properties
        required: true
        schema:
          $ref: "#/definitions/BootSource"
      responses:
        204:
          description: Boot source created/updated
        400:
          description: Boot source cannot be created due to bad input
          schema:
            $ref: "#/definitions/Error"
        default:
          description: Internal server error
          schema:
            $ref: "#/definitions/Error"

  /drives/{drive_id}:
    put:
      summary: Creates or updates a drive.
      description:
        Creates new drive with ID specified by drive_id path parameter.
        If a drive with the specified ID already exists, updates its state based on new input.
        Will fail if update is not possible.
      operationId: putGuestDriveByID
      parameters:
      - name: drive_id
        in: path
        description: The id of the guest drive
        required: true
        type: string
      - name: body
        in: body
        description: Guest drive properties
        required: true
        schema:
          $ref: "#/definitions/Drive"
      responses:
        204:
          description: Drive created/updated
        400:
          description: Drive cannot be created/updated due to bad input
          schema:
            $ref: "#/definitions/Error"
        default:
          description: Internal server error.
          schema:
            $ref: "#/definitions/Error"
    patch:
      summary: Updates the properties of a drive.
      description:
        Updates the properties of the drive with the ID specified by drive_id path parameter.
        Will fail if update is not possible.
      operationId: patchGuestDriveByID
      parameters:
      - name: drive_id
        in: path
        description: The id of the guest drive
        required: true
        type: string
      - name: body
        in: body
        description: Guest drive properties
        required: true
        schema:
          $ref: "#/definitions/PartialDrive"
      responses:
        204:
          description: Drive updated
        400:
          description: Drive cannot be updated due to bad input
          schema:
            $ref: "#/definitions/Error"
        default:
          description: Internal server error.
          schema:
            $ref: "#/definitions/Error"

  /logger:
      put:
        summary: Initializes the logger by specifying two named pipes (i.e. for the logs and metrics output).
        operationId: putLogger
        parameters:
        - name: body
          in: body
          description: Logging system description
          required: true
          schema:
            $ref: "#/definitions/Logger"
        responses:
          204:
            description: Logger created.
          400:
            description: Logger cannot be initialized due to bad input.
            schema:
              $ref: "#/definitions/Error"
          default:
            description: Internal server error.
            schema:
              $ref: "#/definitions/Error"

  /machine-config:
    get:
      summary: Gets the machine configuration of the VM.
      description:
        Gets the machine configuration of the VM. When called before the PUT operation, it
        will return the default values for the vCPU count (=1), memory size (=128 MiB).
        By default Hyperthreading is disabled and there is no CPU Template.
      operationId: getMachineConfiguration
      responses:
        200:
          description: OK
          schema:
            $ref: "#/definitions/MachineConfiguration"
        default:
          description: Internal server error
          schema:
            $ref: "#/definitions/Error"

    put:
      summary: Updates the Machine Configuration of the VM.
      description:
        Updates the Virtual Machine Configuration with the specified input.
        Firecracker starts with default values for vCPU count (=1) and memory size (=128 MiB).
        With Hyperthreading enabled, the vCPU count is restricted to be 1 or an even number,
        otherwise there are no restrictions regarding the vCPU count.
        If any of the parameters has an incorrect value, the whole update fails.
      operationId: putMachineConfiguration
      parameters:
      - name: body
        in: body
        description: Machine Configuration Parameters
        schema:
          $ref: "#/definitions/MachineConfiguration"
      responses:
        204:
          description: Machine Configuration created/updated
        400:
          description: Machine Configuration cannot be updated due to bad input
          schema:
            $ref: "#/definitions/Error"
        default:
          description: Internal server error
          schema:
            $ref: "#/definitions/Error"

    patch:
      summary: Partially updates the Machine Configuration of the VM.
      description:
        Partially updates the Virtual Machine Configuration with the specified input.
        If any of the parameters has an incorrect value, the whole update fails.
      operationId: patchMachineConfiguration
      parameters:
      - name: body
        in: body
        description: A subset of Machine Configuration Parameters
        schema:
          $ref: "#/definitions/MachineConfiguration"
      responses:
        204:
          description: Machine Configuration created/updated
        400:
          description: Machine Configuration cannot be updated due to bad input
          schema:
            $ref: "#/definitions/Error"
        default:
          description: Internal server error
          schema:
            $ref: "#/definitions/Error"

  /mmds:
    put:
      summary: Creates a MMDS (Microvm Metadata Service) data store.
      parameters:
        - name: body
          in: body
          description: The MMDS data store as JSON.
          schema:
            type: object
      responses:
        204:
          description: MMDS data store created/updated.
        400:
          description: MMDS data store cannot be created due to bad input.
          schema:
            $ref: "#/definitions/Error"
        default:
          description: Internal server error
          schema:
            $ref: "#/definitions/Error"
    patch:
      summary: Updates the MMDS data store.
      parameters:
        - name: body
          in: body
          description: The MMDS data store patch JSON.
          schema:
            type: object
      responses:
        204:
          description: MMDS data store updated.
        400:
          description: MMDS data store cannot be updated due to bad input.
          schema:
            $ref: "#/definitions/Error"
        default:
          description: Internal server error
          schema:
            $ref: "#/definitions/Error"
    get:
      summary: Get the MMDS data store.
      responses:
        200:
          description: The MMDS data store JSON.
          schema:
            type: object
        400:
          description: Cannot get the MMDS data store due to bad input.
          schema:
            $ref: "#/definitions/Error"
        default:
          description: Internal server error
          schema:
            $ref: "#/definitions/Error"

  /network-interfaces/{iface_id}:
    put:
      summary: Creates a network interface.
      description:
        Creates new network interface with ID specified by iface_id path parameter.
      operationId: putGuestNetworkInterfaceByID
      parameters:
      - name: iface_id
        in: path
        description: The id of the guest network interface
        required: true
        type: string
      - name: body
        in: body
        description: Guest network interface properties
        required: true
        schema:
          $ref: "#/definitions/NetworkInterface"
      responses:
        204:
          description: Network interface created/updated
        400:
          description: Network interface cannot be created due to bad input
          schema:
            $ref: "#/definitions/Error"
        default:
          description: Internal server error
          schema:
            $ref: "#/definitions/Error"
    patch:
      summary: Updates the rate limiters applied to a network interface.
      description:
        Updates the rate limiters applied to a network interface.
      operationId: patchGuestNetworkInterfaceByID
      parameters:
        - name: iface_id
          in: path
          description: The id of the guest network interface
          required: true
          type: string
        - name: body
          in: body
          description: A subset of the guest network interface properties
          required: true
          schema:
            $ref: "#/definitions/PartialNetworkInterface"
      responses:
        204:
          description: Network interface updated
        400:
          description: Network interface cannot be updated due to bad input
          schema:
            $ref: "#/definitions/Error"
        default:
          description: Internal server error
          schema:
            $ref: "#/definitions/Error"

  /vsock:
    put:
      summary: Creates/updates a vsock device.
      description:
        The first call creates the device with the configuration specified
        in body. Subsequent calls will update the device configuration.
        May fail if update is not possible.
      operationId: putGuestVsock
      parameters:
      - name: body
        in: body
        description: Guest vsock properties
        required: true
        schema:
          $ref: "#/definitions/Vsock"
      responses:
        204:
          description: Vsock created/updated
        400:
          description: Vsock cannot be created due to bad input
          schema:
            $ref: "#/definitions/Error"
        default:
          description: Internal server error
          schema:
            $ref: "#/definitions/Error"

definitions:
  BootSource:
    type: object
    required:
      - kernel_image_path
    description:
      Boot source descriptor.
    properties:
      kernel_image_path:
        type: string
        description: Host level path to the kernel image used to boot the guest
      initrd_path:
        type: string
        description: Host level path to the initrd image used to boot the guest
      boot_args:
        type: string
        description: Kernel boot arguments

  CpuTemplate:
    type: string
    description:
      The CPU Template defines a set of flags to be disabled from the microvm so that
      the features exposed to the guest are the same as in the selected instance type.
    enum:
      - C3
      - T2

  Drive:
    type: object
    required:
      - drive_id
      - path_on_host
      - is_root_device
      - is_read_only
    properties:
      drive_id:
        type: string
      path_on_host:
        type: string
        description: Host level path for the guest drive
      is_root_device:
        type: boolean
      partuuid:
        type: string
        description:
          Represents the unique id of the boot partition of this device. It is
          optional and it will be taken into account only if the is_root_device
          field is true.
      is_read_only:
        type: boolean
      rate_limiter:
        $ref: "#/definitions/RateLimiter"

  Error:
    type: object
    properties:
      fault_message:
        type: string
        description: A description of the error condition
        readOnly: true

  InstanceActionInfo:
    type: object
    description:
      Variant wrapper containing the real action.
    required:
      - action_type
    properties:
      action_type:
        description: Enumeration indicating what type of action is contained in the payload
        type: string
        enum:
        - FlushMetrics
        - InstanceStart
        - SendCtrlAltDel

  InstanceInfo:
    type: object
    description:
      Describes MicroVM instance information.
    required:
      - id
      - state
      - vmm_version
    properties:
      id:
        description: MicroVM / instance ID.
        type: string
      state:
        description:
          The current detailed state of the Firecracker instance.
          This value is read-only for the control-plane.
        type: string
        enum:
          - Uninitialized
          - Starting
          - Running
      vmm_version:
        description: MicroVM hypervisor build version.
        type: string

  Logger:
    type: object
    description:
      Describes the configuration option for the logging capability.
    required:
      - log_fifo
      - metrics_fifo
    properties:
      log_fifo:
        type: string
        description: The named pipe for the human readable log output.
      metrics_fifo:
        type: string
        description: The named pipe where the JSON-formatted metrics will be flushed.
      level:
        type: string
        description: Set the level.
        enum: [Error, Warning, Info, Debug]
        default: Warning
      show_level:
        type: boolean
        description: Whether or not to output the level in the logs.
        default: false
      show_log_origin:
        type: boolean
        description: Whether or not to include the file path and line number of the log's origin.
        default: false

  MachineConfiguration:
    type: object
    description:
      Describes the number of vCPUs, memory size, Hyperthreading capabilities and
      the CPU template.
    required:
      - vcpu_count
      - mem_size_mib
      - ht_enabled
    properties:
      vcpu_count:
        type: integer
        minimum: 1
        maximum: 32
        description: Number of vCPUs (either 1 or an even number)
      mem_size_mib:
        type: integer
        description: Memory size of VM
      ht_enabled:
        type: boolean
        description: Flag for enabling/disabling Hyperthreading
      cpu_template:
        $ref: "#/definitions/CpuTemplate"

  NetworkInterface:
    type: object
    description:
      Defines a network interface.
    required:
      - iface_id
      - host_dev_name
    properties:
      iface_id:
        type: string
      guest_mac:
        type: string
      host_dev_name:
        type: string
        description: Host level path for the guest network interface
      allow_mmds_requests:
        type: boolean
        description:
          If this field is set, the device model will reply to HTTP GET
          requests sent to the MMDS address via this interface. In this case,
          both ARP requests for 169.254.169.254 and TCP segments heading to the
          same address are intercepted by the device model, and do not reach
          the associated TAP device.
      rx_rate_limiter:
        $ref: "#/definitions/RateLimiter"
      tx_rate_limiter:
        $ref: "#/definitions/RateLimiter"

  PartialDrive:
    type: object
    required:
      - drive_id
      - path_on_host
    properties:
      drive_id:
        type: string
      path_on_host:
        type: string
        description: Host level path for the guest drive

  PartialNetworkInterface:
    type: object
    description:
      Defines a partial network interface structure, used to update the rate limiters
      for that interface, after microvm start.
    required:
      - iface_id
    properties:
      iface_id:
        type: string
      rx_rate_limiter:
        $ref: "#/definitions/RateLimiter"
      tx_rate_limiter:
        $ref: "#/definitions/RateLimiter"

  RateLimiter:
    type: object
    description:
      Defines an IO rate limiter with independent bytes/s and ops/s limits.
      Limits are defined by configuring each of the _bandwidth_ and _ops_ token buckets.
    properties:
      bandwidth:
        $ref: "#/definitions/TokenBucket"
        description: Token bucket with bytes as tokens
      ops:
        $ref: "#/definitions/TokenBucket"
        description: Token bucket with operations as tokens

  TokenBucket:
    type: object
    description:
      Defines a token bucket with a maximum capacity (size), an initial burst size
      (one_time_burst) and an interval for refilling purposes (refill_time).
      The refill-rate is derived from size and refill_time, and it is the constant
      rate at which the tokens replenish. The refill process only starts happening after
      the initial burst budget is consumed.
      Consumption from the token bucket is unbounded in speed which allows for bursts
      bound in size by the amount of tokens available.
      Once the token bucket is empty, consumption speed is bound by the refill_rate.
    required:
      - size
      - refill_time
    properties:
      size:
        type: integer
        format: int64
        description: The total number of tokens this bucket can hold.
        minimum: 0
      one_time_burst:
        type: integer
        format: int64
        description: The initial size of a token bucket.
        minimum: 0
      refill_time:
        type: integer
        format: int64
        description: The amount of milliseconds it takes for the bucket to refill.
        minimum: 0

  Vsock:
    type: object
    description:
      Defines a vsock device, backed by a set of Unix Domain Sockets, on the host side.
      For host-initiated connections, Firecracker will be listening on the Unix socket
      identified by the path `uds_path`. Firecracker will create this socket, bind and
      listen on it. Host-initiated connections will be performed by connection to this
      socket and issuing a connection forwarding request to the desired guest-side vsock
      port (i.e. `CONNECT 52\n`, to connect to port 52).
      For guest-initiated connections, Firecracker will expect host software to be
      bound and listening on Unix sockets at `uds_path_<PORT>`.
      E.g. "/path/to/host_vsock.sock_52" for port number 52.
    required:
      - vsock_id
      - guest_cid
      - uds_path
    properties:
      vsock_id:
        type: string
      guest_cid:
        type: integer
        minimum: 3
        description: Guest Vsock CID
      uds_path:
        type: string
        description: Path to UNIX domain socket, used to proxy vsock connections.