Firecracker

Firecracker Hotplug API

The Hotplug API from Firecracker — 1 operation(s) for hotplug.

GitHub OpenAPI

Operations 3

PUT /hotplug/memory Configures the hotpluggable memory #
PATCH /hotplug/memory Updates the size of the hotpluggable memory region #
GET /hotplug/memory Retrieves the status of the hotpluggable memory #

Documentation

📖
Documentation
https://github.com/firecracker-microvm/firecracker/tree/main/docs
📖
GettingStarted
https://github.com/firecracker-microvm/firecracker/blob/main/docs/getting-started.md

Specifications

⚙
OpenAPI
https://raw.githubusercontent.com/api-evangelist/firecracker/refs/heads/main/openapi/firecracker-hotplug-api-openapi.yml

Other Resources

🔗
API Requests
https://github.com/firecracker-microvm/firecracker/tree/main/docs/api_requests
🔗
Specification
https://github.com/firecracker-microvm/firecracker/blob/main/SPECIFICATION.md
🔗
Design
https://github.com/firecracker-microvm/firecracker/blob/main/docs/design.md

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OpenAPI Specification

firecracker-hotplug-api-openapi.yml Raw ↑ 
openapi: 3.2.0
info:
  title: Firecracker Actions Hotplug 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: 1.16.0-dev
  termsOfService: ''
  contact:
    email: firecracker-maintainers@amazon.com
  license:
    name: Apache 2.0
    url: http://www.apache.org/licenses/LICENSE-2.0.html
servers:
- url: http://localhost/
tags:
- name: Hotplug
paths:
  /hotplug/memory:
    put:
      summary: Configures the hotpluggable memory
      operationId: putMemoryHotplug
      description: Configure the hotpluggable memory, which is a virtio-mem device, with an associated memory area that can be hot(un)plugged in the guest on demand using the PATCH API.
      responses:
        204:
          description: Hotpluggable memory configured
        default:
          description: Internal server error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
      tags:
      - Hotplug
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/MemoryHotplugConfig'
        description: Hotpluggable memory configuration
        required: true
    patch:
      summary: Updates the size of the hotpluggable memory region
      operationId: patchMemoryHotplug
      description: Updates the size of the hotpluggable memory region. The guest will plug and unplug memory to hit the requested memory.
      responses:
        204:
          description: Hotpluggable memory configured
        default:
          description: Internal server error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
      tags:
      - Hotplug
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/MemoryHotplugSizeUpdate'
        description: Hotpluggable memory size update
        required: true
    get:
      summary: Retrieves the status of the hotpluggable memory
      operationId: getMemoryHotplug
      description: Reuturn the status of the hotpluggable memory. This can be used to follow the progress of the guest after a PATCH API.
      responses:
        200:
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/MemoryHotplugStatus'
        default:
          description: Internal server error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
      tags:
      - Hotplug
components:
  schemas:
    Error:
      type: object
      properties:
        fault_message:
          type: string
          description: A description of the error condition
          readOnly: true
    MemoryHotplugStatus:
      type: object
      description: The status of the hotpluggable memory device (virtio-mem)
      properties:
        total_size_mib:
          type: integer
          description: Total size of the hotpluggable memory in MiB.
        slot_size_mib:
          type: integer
          description: Slot size for the hotpluggable memory in MiB.
        block_size_mib:
          type: integer
          description: (Logical) Block size for the hotpluggable memory in MiB.
        plugged_size_mib:
          type: integer
          description: Plugged size for the hotpluggable memory in MiB.
        requested_size_mib:
          type: integer
          description: Requested size for the hotpluggable memory in MiB.
    MemoryHotplugConfig:
      type: object
      description: The configuration of the hotpluggable memory device (virtio-mem)
      properties:
        total_size_mib:
          type: integer
          description: Total size of the hotpluggable memory in MiB.
        slot_size_mib:
          type: integer
          default: 128
          minimum: 128
          description: Slot size for the hotpluggable memory in MiB. This will determine the granularity of hot-plug memory from the host. Refer to the device documentation on how to tune this value.
        block_size_mib:
          type: integer
          default: 2
          minimum: 2
          description: (Logical) Block size for the hotpluggable memory in MiB. This will determine the logical granularity of hot-plug memory for the guest. Refer to the device documentation on how to tune this value.
    MemoryHotplugSizeUpdate:
      type: object
      description: An update to the size of the hotpluggable memory region.
      properties:
        requested_size_mib:
          type: integer
          description: New target region size.