doc-exports/docs/ecs/api-ref/en-us_topic_0067876971.html

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

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.

This API is an asynchronous API. After the OS change request is successfully delivered, a job ID is returned. This does not mean the OS change is complete. You need to call the API by referring to Querying Job Execution Status to query the job status. The SUCCESS status indicates that the OS change is successful.

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

• This API only supports images with Cloud-Init or Cloudbase-Init installed.
• OS changes are only supported on stopped ECSs or on ECSs where OS reinstallation or change has failed.
• ECSs without system disks do not support OS changes.
• You are not allowed to perform other operations when changing the OS, or the OS change may 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	Definition Changes an ECS OS. For details, see Table 3. Constraints N/A Range N/A Default Value N/A

Table 3 os-change field description

Parameter	Mandatory	Type	Description
keyname	Yes	String	Definition Specifies the key name. Constraints N/A Range N/A Default Value N/A
userid	No	String	Definition Specifies the user ID. Constraints 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. Range N/A Default Value N/A
imageid	Yes	String	Definition 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. Constraints N/A Range N/A Default Value N/A
metadata	No	Object	Definition Specifies the metadata of the ECS for which the OS is to be changed. For more information, see Table 4. Constraints N/A Range N/A Default Value N/A

Table 4 metadata field description

Parameter	Mandatory	Type	Description
BYOL	No	String	Definition Specifies whether a user has the license of an image. Constraints N/A Range 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 cloud platform must be used. Default Value The default value is not true, indicating that BYOL is not used.
user_data	No	String	Definition Specifies the user data to be injected to the ECS during the creation. Text and text files can be injected. 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 IyEvYmluL2Jhc2gKZWNobyB1c2VyX3Rlc3QgPiAvaG9tZS91c2VyLnR4dA== Windows cmVtIGNtZAplY2hvIDExMSA+IGM6XGFhYS50eHQ= For more details, see "Injecting User Data into ECSs" in the Elastic Cloud Server User Guide. Constraints The content of user_data must be encoded with base64. The maximum size of the content to be injected (before encoding) is 32 KB. Range N/A Default Value N/A
__system__encrypted	No	String	Definition Specifies the encryption field in metadata. Constraints N/A Range 0: indicates a non-encrypted disk. 1: indicates an encrypted disk. Default Value If this parameter does not exist, the system disk will not be encrypted by default.
__system__cmkid	No	String	Definition Specifies the CMK ID, which indicates encryption in metadata. Constraints This parameter must be used with __system__encrypted. NOTE: For details about how to obtain the CMK ID through HTTPS requests, see "Querying the Key List" in Key Management Service API Reference. Range N/A Default Value N/A

Response

Table 5 describes the response parameters.

Table 5 Response parameters

Parameter	Type	Description
job_id	String	Definition Specifies the job ID returned after a job is delivered. The job ID can be used to query the job execution progress. For details about how to query the job execution status based on job_id, see Job Status Management. Range N/A

For details about abnormal responses, see Responses (Jobs).

Example Request

• After the ECS OS is switched, use the password for login authentication. For security purposes, store the password in ciphertext in configuration files or environment variables.

  POST https://{endpoint}/v2/{project_id}/cloudservers/{server_id}/changeos
  
  {
      "os-change": {
          "userid": "7e25b1da389f4697a79df3a0e5bd494e", 
          "imageid": "e215580f-73ad-429d-b6f2-5433947433b0"
      }
  }

• Change the OS and use the key pair for login authentication after the OS change.

  POST https://{endpoint}/v2/{project_id}/cloudservers/{server_id}/changeos
  
  {
      "os-change": {
          "keyname": "KeyPair-350b", 
          "userid": "7e25b1da389f4697a79df3a0e5bd494e", 
          "imageid": "e215580f-73ad-429d-b6f2-5433947433b0"
      }
  }

• If the ECS OS is switched using encrypted full-ECS images of the system disk, use the password for login authentication. For security purposes, store the password in ciphertext in configuration files or environment variables.

  POST https://{endpoint}/v2/{project_id}/cloudservers/{server_id}/changeos
  
  {
      "os-change": {
          "userid": "7e25b1da389f4697a79df3a0e5bd494e", 
          "imageid": "e215580f-73ad-429d-b6f2-5433947433b0", 
          "metadata": {
                "__system__encrypted": "1",
                "__system__cmkid": "83cdb52d-9ebf-4469-9cfa-e7b5b80da846"
          }
      }
  }

Example Response

See Responses (Jobs).

{      
    "job_id": "ff80808288d41e1b018990260955686a" 
}

Returned Values

See Returned Values for General Requests.

Error Codes

See Error Codes.

Parent topic: Status Management