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: 0.21.0
  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. Pre-boot only.
      description:
        Creates new boot source if one does not already exist, otherwise updates it.
        Will fail if update is not possible.
      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. Pre-boot only.
      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. Post-boot only.
      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 a named pipe or a file for the logs 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. Pre-boot only.
      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. Pre-boot only.
      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"

  /metrics:
    put:
      summary: Initializes the metrics system by specifying a named pipe or a file for the metrics output.
      operationId: putMetrics
      parameters:
        - name: body
          in: body
          description: Metrics system description
          required: true
          schema:
            $ref: "#/definitions/Metrics"
      responses:
        204:
          description: Metrics system created.
        400:
          description: Metrics system cannot be initialized 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
        404:
          description: The MMDS data store content can not be found.
          schema:
            $ref: "#/definitions/Error"
        default:
          description: Internal server error
          schema:
            $ref: "#/definitions/Error"

  /mmds/config:
    put:
      summary: Set MMDS configuration. Pre-boot only.
      description:
        Creates MMDS configuration to be used by the MMDS network stack.
      parameters:
        - name: body
          in: body
          description: The MMDS configuration as JSON.
          required: true
          schema:
            $ref: "#/definitions/MmdsConfig"
      responses:
        204:
          description: MMDS configuration was created/updated.
        400:
          description: MMDS configuration cannot be updated 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. Pre-boot only.
      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. Post-boot only.
      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"

  /snapshot/create:
    put:
      summary: Creates a full or diff snapshot. Post-boot only.
      description:
        Creates a snapshot of the microVM state. The microVM should be
        in the `Paused` state.
      operationId: createSnapshot
      parameters:
        - name: body
          in: body
          description: The configuration used for creating a snaphot.
          required: true
          schema:
            $ref: "#/definitions/SnapshotCreateParams"
      responses:
        204:
          description: Snapshot created
        400:
          description: Snapshot cannot be created due to bad input
          schema:
            $ref: "#/definitions/Error"
        default:
          description: Internal server error
          schema:
            $ref: "#/definitions/Error"

  /snapshot/load:
    put:
      summary: Loads a snapshot. Pre-boot only.
      description:
        Loads the microVM state from a snapshot.
        Only accepted on a fresh Firecracker process (before configuring
        any resource other than the Logger).
      operationId: loadSnapshot
      parameters:
        - name: body
          in: body
          description: The configuration used for loading a snaphot.
          required: true
          schema:
            $ref: "#/definitions/SnapshotLoadParams"
      responses:
        204:
          description: Snapshot loaded
        400:
          description: Snapshot cannot be loaded due to bad input
          schema:
            $ref: "#/definitions/Error"
        default:
          description: Internal server error
          schema:
            $ref: "#/definitions/Error"

  /vm:
    patch:
      summary: Updates the microVM state.
      description:
        Sets the desired state (Paused or Resumed) for the microVM.
      operationId: patchVm
      parameters:
        - name: body
          in: body
          description: The microVM state
          required: true
          schema:
            $ref: "#/definitions/Vm"
      responses:
        204:
          description: Vm state updated
        400:
          description: Vm state 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. Pre-boot only.
      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:
      boot_args:
        type: string
        description: Kernel boot arguments
      initrd_path:
        type: string
        description: Host level path to the initrd image used to boot the guest
      kernel_image_path:
        type: string
        description: Host level path to the kernel image used to boot the guest

  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
      - is_read_only
      - is_root_device
      - path_on_host
    properties:
      drive_id:
        type: string
      is_read_only:
        type: boolean
      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.
      path_on_host:
        type: string
        description: Host level path for the guest drive
      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:
      app_name:
        description: Application name.
        type: string
      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_path
    properties:
      level:
        type: string
        description: Set the level.
        enum: [Error, Warning, Info, Debug]
        default: Warning
      log_path:
        type: string
        description: Path to the named pipe or file for the human readable log output.
      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:
      - ht_enabled
      - mem_size_mib
      - vcpu_count
    properties:
      cpu_template:
        $ref: "#/definitions/CpuTemplate"
      ht_enabled:
        type: boolean
        description: Flag for enabling/disabling Hyperthreading
      mem_size_mib:
        type: integer
        description: Memory size of VM
      track_dirty_pages:
        type: boolean
        description:
          Enable dirty page tracking. If this is enabled, then incremental guest memory
          snapshots can be created. These belong to diff snapshots, which contain, besides
          the microVM state, only the memory dirtied since a previous snapshot. Full snapshots
          each contain a full copy of the guest memory.
      vcpu_count:
        type: integer
        minimum: 1
        maximum: 32
        description: Number of vCPUs (either 1 or an even number)

  Metrics:
    type: object
    description:
      Describes the configuration option for the metrics capability.
    required:
      - metrics_path
    properties:
      metrics_path:
        type: string
        description: Path to the named pipe or file where the JSON-formatted metrics are flushed.

  MmdsConfig:
    type: object
    description:
      Defines the MMDS configuration.
    properties:
      ipv4_address:
        type: string
        format: "169.254.([1-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-4]).([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])"
        default: "169.254.169.254"
        description: A valid IPv4 link-local address.

  NetworkInterface:
    type: object
    description:
      Defines a network interface.
    required:
      - host_dev_name
      - iface_id
    properties:
      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.
      guest_mac:
        type: string
      host_dev_name:
        type: string
        description: Host level path for the guest network interface
      iface_id:
        type: string
      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

  SnapshotCreateParams:
    type: object
    required:
      - mem_file_path
      - snapshot_path
    properties:
      mem_file_path:
        type: string
        description: Path to the file that will contain the guest memory.
      snapshot_path:
        type: string
        description: Path to the file that will contain the microVM state.
      snapshot_type:
        type: string
        enum:
          - Full
          - Diff
        description:
          Type of snapshot to create. It is optional and by default, a full
          snapshot is created.
      version:
        type: string
        description:
          The microVM version for which we want to create the snapshot.
          It is optional and it defaults to the current version.

  SnapshotLoadParams:
    type: object
    required:
      - mem_file_path
      - snapshot_path
    properties:
      enable_diff_snapshots:
        type: boolean
        description:
          Enable support for incremental (diff) snapshots by tracking dirty guest pages.
      mem_file_path:
        type: string
        description: Path to the file that contains the guest memory to be loaded.
      snapshot_path:
        type: string
        description: Path to the file that contains the microVM state to be loaded.

  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:
      - refill_time
      - size
    properties:
      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
      size:
        type: integer
        format: int64
        description: The total number of tokens this bucket can hold.
        minimum: 0

  Vm:
    type: object
    description:
      Defines the microVM running state. It is especially useful in the snapshotting context.
    required:
      - state
    properties:
      state:
        type: string
        enum:
          - Paused
          - Resumed

  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:
      - guest_cid
      - uds_path
      - vsock_id
    properties:
      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.
      vsock_id:
        type: string