systemd Units API

openapi: 3.2.0
info:
  title: systemd-hostnamed (org.freedesktop.hostname1) Boot Units API
  version: '1.0'
  summary: D-Bus API of systemd-hostnamed modeled as REST operations.
  description: 'Documentation/contract artifact for the `org.freedesktop.hostname1` D-Bus interface on the

    system bus. Manages the system hostname (static, transient, pretty), chassis type, deployment,

    location, icon name, and other machine info.

    '
  license:
    name: LGPL-2.1-or-later
    url: https://github.com/systemd/systemd/blob/main/LICENSES/LGPL-2.1-or-later.txt
servers:
- url: dbus://system/org.freedesktop.hostname1
tags:
- name: Units
  description: Unit lifecycle and enumeration.
paths:
  /units:
    get:
      tags:
      - Units
      operationId: ListUnits
      summary: List All Loaded Units
      description: Returns an array of all currently loaded units. Mirrors `ListUnits()` on the Manager.
      responses:
        '200':
          description: Array of units (name, description, load state, active state, sub state, follower, object path, job id, job type, job object path).
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/Unit'
  /units/{name}:
    parameters:
    - name: name
      in: path
      required: true
      schema:
        type: string
      description: Unit name (e.g. `nginx.service`).
    get:
      tags:
      - Units
      operationId: GetUnit
      summary: Get A Loaded Unit By Name
      description: Returns the D-Bus object path of an already-loaded unit. Mirrors `GetUnit(name)`.
      responses:
        '200':
          description: Object path of the unit.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/UnitPath'
        '404':
          description: Unit not loaded.
  /units/{name}/load:
    parameters:
    - name: name
      in: path
      required: true
      schema:
        type: string
    post:
      tags:
      - Units
      operationId: LoadUnit
      summary: Load A Unit From Disk
      description: Forces the Manager to load the named unit and returns its object path. Mirrors `LoadUnit(name)`.
      responses:
        '200':
          description: Loaded unit object path.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/UnitPath'
  /units/{name}/start:
    parameters:
    - name: name
      in: path
      required: true
      schema:
        type: string
    post:
      tags:
      - Units
      operationId: StartUnit
      summary: Start A Unit
      description: Enqueues a start job for the unit. Mirrors `StartUnit(name, mode)`. Mode is one of `replace`, `fail`, `isolate`, `ignore-dependencies`, `ignore-requirements`.
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/JobModeRequest'
      responses:
        '202':
          description: Job enqueued; returns job object path.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/JobPath'
  /units/{name}/stop:
    parameters:
    - name: name
      in: path
      required: true
      schema:
        type: string
    post:
      tags:
      - Units
      operationId: StopUnit
      summary: Stop A Unit
      description: Enqueues a stop job. Mirrors `StopUnit(name, mode)`.
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/JobModeRequest'
      responses:
        '202':
          description: Job enqueued.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/JobPath'
  /units/{name}/restart:
    parameters:
    - name: name
      in: path
      required: true
      schema:
        type: string
    post:
      tags:
      - Units
      operationId: RestartUnit
      summary: Restart A Unit
      description: Stops then starts. Mirrors `RestartUnit(name, mode)`.
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/JobModeRequest'
      responses:
        '202':
          description: Job enqueued.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/JobPath'
  /units/{name}/reload:
    parameters:
    - name: name
      in: path
      required: true
      schema:
        type: string
    post:
      tags:
      - Units
      operationId: ReloadUnit
      summary: Reload A Unit
      description: Asks a unit to reload its configuration (e.g. SIGHUP for services). Mirrors `ReloadUnit(name, mode)`.
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/JobModeRequest'
      responses:
        '202':
          description: Job enqueued.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/JobPath'
  /units/{name}/reload-or-restart:
    parameters:
    - name: name
      in: path
      required: true
      schema:
        type: string
    post:
      tags:
      - Units
      operationId: ReloadOrRestartUnit
      summary: Reload Or Restart A Unit
      description: Reloads if supported, otherwise restarts. Mirrors `ReloadOrRestartUnit(name, mode)`.
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/JobModeRequest'
      responses:
        '202':
          description: Job enqueued.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/JobPath'
  /units/{name}/kill:
    parameters:
    - name: name
      in: path
      required: true
      schema:
        type: string
    post:
      tags:
      - Units
      operationId: KillUnit
      summary: Send A Signal To A Unit
      description: Sends a UNIX signal to the unit's main, control, or all processes. Mirrors `KillUnit(name, who, signal)`.
      requestBody:
        content:
          application/json:
            schema:
              type: object
              required:
              - who
              - signal
              properties:
                who:
                  type: string
                  enum:
                  - main
                  - control
                  - all
                signal:
                  type: integer
                  description: UNIX signal number (e.g. 15 = SIGTERM
                  9 = SIGKILL).: null
      responses:
        '204':
          description: Signal sent.
  /units/{name}/freeze:
    parameters:
    - name: name
      in: path
      required: true
      schema:
        type: string
    post:
      tags:
      - Units
      operationId: FreezeUnit
      summary: Freeze A Unit's Cgroup
      description: Suspends all processes in the unit's cgroup using the cgroup v2 freezer. Mirrors `FreezeUnit(name)`.
      responses:
        '204':
          description: Frozen.
  /units/{name}/thaw:
    parameters:
    - name: name
      in: path
      required: true
      schema:
        type: string
    post:
      tags:
      - Units
      operationId: ThawUnit
      summary: Thaw A Unit's Cgroup
      description: Resumes a frozen cgroup. Mirrors `ThawUnit(name)`.
      responses:
        '204':
          description: Thawed.
  /units/{name}/properties:
    parameters:
    - name: name
      in: path
      required: true
      schema:
        type: string
    get:
      tags:
      - Units
      operationId: GetAllUnitProperties
      summary: Get All Properties Of A Unit
      description: Returns the full property bag for a unit. Equivalent to `org.freedesktop.DBus.Properties.GetAll`.
      responses:
        '200':
          description: Unit property map.
          content:
            application/json:
              schema:
                type: object
                additionalProperties: true
    patch:
      tags:
      - Units
      operationId: SetUnitProperties
      summary: Set Runtime Properties On A Unit
      description: Sets one or more properties at runtime. Mirrors `SetUnitProperties(name, runtime, properties)`. Used for live cgroup resource changes (CPUWeight, MemoryMax, etc.).
      requestBody:
        content:
          application/json:
            schema:
              type: object
              properties:
                runtime:
                  type: boolean
                  description: If true
                  changes apply only until reboot.: null
                properties:
                  type: object
                  additionalProperties: true
      responses:
        '204':
          description: Properties updated.
  /units/transient:
    post:
      tags:
      - Units
      operationId: StartTransientUnit
      summary: Start A Transient Unit
      description: Creates and starts a new transient unit (typically a scope or service) with the supplied properties. Mirrors `StartTransientUnit(name, mode, properties, aux)`.
      requestBody:
        content:
          application/json:
            schema:
              type: object
              required:
              - name
              - mode
              properties:
                name:
                  type: string
                mode:
                  type: string
                  enum:
                  - replace
                  - fail
                  - isolate
                  - ignore-dependencies
                  - ignore-requirements
                properties:
                  type: object
                  additionalProperties: true
                aux:
                  type: array
                  items:
                    type: object
      responses:
        '202':
          description: Job enqueued.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/JobPath'
components:
  schemas:
    JobModeRequest:
      type: object
      properties:
        mode:
          type: string
          enum:
          - replace
          - fail
          - isolate
          - ignore-dependencies
          - ignore-requirements
          default: replace
    Unit:
      type: object
      properties:
        name:
          type: string
        description:
          type: string
        load_state:
          type: string
          enum:
          - stub
          - loaded
          - not-found
          - bad-setting
          - error
          - merged
          - masked
        active_state:
          type: string
          enum:
          - active
          - reloading
          - inactive
          - failed
          - activating
          - deactivating
        sub_state:
          type: string
        follower:
          type: string
          nullable: true
        object_path:
          type: string
        job_id:
          type: integer
        job_type:
          type: string
        job_object_path:
          type: string
    JobPath:
      type: object
      properties:
        path:
          type: string
          description: D-Bus object path of the job.
    UnitPath:
      type: object
      properties:
        path:
          type: string
          description: D-Bus object path.