Help Center/ Elastic Cloud Server/ API Reference (Kuala Lumpur Region)/ APIs (Recommended)/ Status Management/ Changing an ECS OS (Using an Image with Cloud-Init Installed)
Updated on 2024-07-23 GMT+08:00
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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 Task 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

  • You can only use an image with Cloud-Init or Cloudbase-Init installed. If the image has no Cloudbase-Init or Cloudbase-init installed, use the API described in Changing an ECS OS (Using an Image Without Cloud-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.

For details about how to obtain the ID, see Obtaining a 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

adminpass

No

String

Specifies the initial password of the ECS administrator.

The Windows administrator username is Administrator, and the Linux administrator username is root.

The password must meet the following requirements:

  • 8 to 26 characters
  • The password must contain at least three of the following character types: uppercase letters, lowercase letters, digits, and special characters (!@$%^-_=+[{}]:,./?~#*).
NOTE:
  • The Windows ECS password cannot contain the username, the username in reverse, or more than two characters in the same sequence as they appear in the username.
  • Linux ECSs can use user_data to inject passwords. In such a case, adminpass is unavailable.
  • Specify either adminpass or keyname, not both of them.
  • If both adminpass and keyname are empty, user_data in metadata must be set.
  • If you use this field to change the OS of an ECS with Cloud-Init installed, the region in which the ECS is deployed does not support password-authenticated OS changing. In such a case, use key pair authentication.

keyname

No

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

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 the 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 
    IyEvYmluL2Jhc2gKZWNobyB1c2VyX3Rlc3QgPiAvaG9tZS91c2VyLnR4dA==
  • Windows 
    cmVtIGNtZAplY2hvIDExMSA+IGM6XGFhYS50eHQ=

Response

See Responses (Task).

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": {
        "adminpass": "$ADMIN_PASS",
        "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"
    }
}

Example Response

See Responses (Task).

{      
    "job_id": "ff80808288d41e1b018990260955686a" 
}

Returned Values

See Returned Values for General Requests.

Error Codes

See Error Codes.

Parent topic: Status Management