> ## Documentation Index
> Fetch the complete documentation index at: https://vastai-80aa3a82-auto-openapi-update-8483c1e9.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Update Instance Template

> Updates the image, environment, or template associated with an existing instance, optionally recycling it immediately.



## OpenAPI

````yaml /api-reference/openapi.yaml put /api/v0/instances/update_template/{id}/
openapi: 3.1.0
info:
  title: Vast.ai API
  description: >-
    Vast.ai REST API for managing GPU cloud instances, machine operations, and
    AI/ML workflows.


    ## AI Agent Quick-Start


    Install the CLI skill for your agent (Claude Code, Cursor, Windsurf, etc.):
      npx skills add vast-ai/vast-cli

    CLI reference:
    https://raw.githubusercontent.com/vast-ai/vast-cli/master/vastai/SKILL.md

    SDK reference:
    https://raw.githubusercontent.com/vast-ai/vast-cli/master/vastai_sdk/SKILL.md


    ## Auth

    All endpoints require `Authorization: Bearer $VAST_API_KEY`.

    Get your key at: https://cloud.vast.ai/manage-keys/


    ## Key Quirks

    - `gpu_ram` in CLI = GB; in REST API = MB (CLI auto-converts)

    - SSH keys must be registered BEFORE creating an instance (VM: no recovery;
    Docker: can add post-create)

    - `onstart` field is limited to 4048 characters -- gzip+base64 for longer
    scripts

    - `POST /api/v0/asks/{id}/` (create instance) returns `new_contract` as the
    instance ID, not `id`

    - Poll trap: if `actual_status` becomes `exited`, `unknown`, or `offline` it
    will never reach `running` -- destroy and retry
  version: 1.0.0
  contact:
    name: Vast.ai Support
    url: https://discord.gg/vast
servers:
  - url: https://console.vast.ai
    description: Production server
security:
  - BearerAuth: []
paths:
  /api/v0/instances/update_template/{id}/:
    put:
      tags:
        - Instances
      summary: Update Instance Template
      description: >-
        Updates the image, environment, or template associated with an existing
        instance, optionally recycling it immediately.
      parameters:
        - name: id
          in: path
          required: true
          schema:
            type: integer
          description: Instance contract ID whose template to update.
      requestBody:
        content:
          application/json:
            schema:
              type: object
              properties:
                template_id:
                  type: integer
                  description: Numeric ID of an existing template to apply to the instance.
                  example: 99
                template_hash_id:
                  type: string
                  description: >-
                    Hash ID of an existing template to apply; takes precedence
                    over template_id.
                  example: abc123def456
                image:
                  type: string
                  description: Docker image reference to set on the instance.
                  example: pytorch/pytorch:2.0.0-cuda11.7-cudnn8-runtime
                onstart:
                  type: string
                  description: Shell script to run when the instance starts.
                  example: pip install mypackage
                image_login:
                  type: string
                  description: >-
                    Docker registry login credentials used to pull a private
                    image, in the format '-u <username> -p <password>
                    <registry>'.
                  example: '-u myuser -p mypass docker.io'
                disk:
                  type: number
                  description: Disk allocation in GB; minimum 8 GB.
                  example: 20
                recycle:
                  type: boolean
                  description: >-
                    If true, immediately recycle the instance after applying the
                    template update.
                  example: true
      responses:
        '200':
          description: >-
            Returns {success: true} on successful update, or the recycle
            response {success: true/false} if recycle was requested.
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
                    description: True when update succeeded
              example:
                success: true
        '400':
          description: >-
            Returns {success: false, error: "missing_id", msg: "Instance ID is
            required"} when id is absent.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '404':
          description: >-
            Returns {success: false, error: "not_found", msg: "Instance not
            found or you don't have permission to modify it"} when the instance
            doesn't exist for the user.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
      security:
        - BearerAuth: []
components:
  schemas:
    Error:
      type: object
      properties:
        error:
          type: string
        msg:
          type: string
  securitySchemes:
    BearerAuth:
      type: http
      scheme: bearer
      description: API key must be provided in the Authorization header

````