Function

This API is used to change an ECS OS. During the system disk reinstallation using a new image, the data disks of the ECS remain unchanged.

After this API is called, the system uninstalls the system disk, uses the new image to create a system disk, and attaches it to the ECS. In this way, the OS is changed.

Constraints

You can only use an image with Cloud-Init or Cloudbase-Init installed.
Only a stopped ECS or an ECS on which reinstalling or changing the OS failed supports changing OS.
Only an ECS with a system disk supports changing OS.
You are not allowed to perform other operations when changing the OS. Otherwise, changing the OS will fail.

URI

POST /v2/{project_id}/cloudservers/{server_id}/changeos

Table 1 describes the parameters in the URI.

**Table 1** Parameter description
Parameter	Mandatory	Description
project_id	Yes	Specifies the project ID.
server_id	Yes	Specifies the ECS ID.

Request

Table 2 describes the request parameters.

**Table 2** Request parameters
Parameter	Mandatory	Type	Description
os-change	Yes	Object	Changes an ECS OS. For details, see Table 3.

**Table 3** **os-change** field description
Parameter	Mandatory	Type	Description
keyname	Yes	String	Specifies the key pair name.
userid	No	String	Specifies the user ID. When the keyname parameter is being specified, the value of this parameter is used preferentially. If this parameter is left blank, the user ID in the token is used by default.
imageid	Yes	String	Specifies the ID of the new image in UUID format. You can obtain the image ID from the console or by following the instructions provided in "Querying Images" in Image Management Service API Reference.
metadata	No	Object	Specifies the metadata of the ECS for which the OS is to be changed. For more information, see Table 4.

**Table 4** **metadata** field description
Parameter	Mandatory	Type	Description
BYOL	No	String	Specifies whether a user has the license of an image. If this parameter is set to true, the license file delivered with the image is used, indicating that BYOL is used. If this parameter is set to a value other than true, BYOL is not used, and the license file provided by the public cloud platform must be used. The default value is not true, indicating that BYOL is not used.
user_data	No	String	Specifies the user data to be injected to the ECS during the creation. Text and text files can be injected. NOTE: The content of user_data must be encoded with base64. The maximum size of the content to be injected (before encoding) is 32 KB. For more details, see "Injecting User Data into ECSs" in Elastic Cloud Server User Guide. Examples Before base64 encoding: Linux #! /bin/bash echo user_test >> /home/user.txt Windows rem cmd echo 111 > c:\aaa.txt After base64 encoding: Linux IyEgL2Jpbi9iYXNoDQplY2hvIHVzZXJfdGVzdCAmZ3Q7Jmd0OyAvaG9tZS91c2VyLnR4dA== Windows cmVtIGNtZAplY2hvIDExMSA+IGM6XGFhYS50eHQ=
__system__encrypted	No	String	Specifies encryption in metadata. The value can be 0 (encryption disabled) or 1 (encryption enabled). If this parameter does not exist, the system disk will not be encrypted by default.
__system__cmkid	No	String	Specifies the CMK ID, which indicates encryption in metadata. This parameter is used with __system__encrypted. NOTE: For details about how to obtain the CMK ID, see "Querying the List of CMKs" in Key Management Service API Reference.

Response

See Responses (Task).

Example Request

Example URL request

POST https://{endpoint}/v2/{project_id}/cloudservers/{server_id}/changeos

Example request 1 (using a password to remotely log in to an ECS with OS changed)

{
    "os-change": {
        "adminpass": "1qazXSW@", 
        "userid": "7e25b1da389f4697a79df3a0e5bd494e", 
        "imageid": "e215580f-73ad-429d-b6f2-5433947433b0"
    }
}

Example request 2 (using a key to remotely log in to an ECS with OS changed)

{
    "os-change": {
        "keyname": "KeyPair-350b", 
        "userid": "7e25b1da389f4697a79df3a0e5bd494e", 
        "imageid": "e215580f-73ad-429d-b6f2-5433947433b0"
    }
}

Example request 3 (using a password to remotely log in a full-ECS-image-created ECS with OS changed and system disk encrypted)

{
    "os-change": {
        "adminpass": "1qazXSW@", 
        "userid": "7e25b1da389f4697a79df3a0e5bd494e", 
        "imageid": "e215580f-73ad-429d-b6f2-5433947433b0", 
        "metadata": {
              "__system__encrypted": "1",
              "__system__cmkid": "83cdb52d-9ebf-4469-9cfa-e7b5b80da846"
        }
    }
}

Example Response

See Responses (Task).

{      
    "job_id": "70a599e0-31e7-49b7-b260-868f441e862b" 
}

Returned Values

See Returned Values for General Requests.

Error Codes

See Error Codes.

Changing an ECS OS (Using an Image with Cloud-Init Installed)