Attaching a Disk to an ECS¶

Function¶

This API is used to attach a disk to an ECS.

This API is an asynchronous API. After the attachment request is successfully delivered, a job ID is returned. This does not mean the attachment 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 attachment is successful.

URI¶

POST /v1/{project_id}/cloudservers/{server_id}/attachvolume

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** Request parameters¶
Parameter	Mandatory	Type	Description
volumeAttachment	Yes	Object	Specifies the ECS attachment information. For details, see Table 3.
dry_run	No	Boolean	Specifies whether to check the request and attach the disk. true: indicates that only the request is sent, and no disk will be attached. Check items include mandatory parameters, request format, and service restrictions. If the check fails, the system returns an error. If the check result is as expected, the system properly responds. false: indicates that only the request is sent and the disk will be attached if the check result is as expected. The default value is false.

**Table 3** **volumeAttachment** field description¶
Parameter	Mandatory	Type	Description
volumeId	Yes	String	Specifies the ID of the disk to be attached. The value is in UUID format.
device	No	String	Indicates the disk device name. Note The new disk device name cannot be the same as an existing one. For KVM ECSs, set the parameter value to /dev/vda for system disks. The device names for data disks of KVM ECSs are optional. If the device names of data disks are required, set them in alphabetical order. For example, if there are two data disks, set the device names of the two data disks to /dev/vdb and /dev/vdc, respectively. If you set a device name starting with /dev/sd, the system uses /dev/vd by default. For ECSs that only support SCSI disks, set the device name of the system disk to /dev/sda and the device names of data disks in alphabetical order, for example, /dev/sdb and /dev/sdc. The system will not change the default device names.
volume_type	No	String	Specifies the disk type.
count	No	Integer	Specifies the number of disks.
hw:passthrough	No	String	If this parameter is set to true, the disk device type is SCSI, which allows ECS OSs to directly access the underlying storage media. SCSI reservation commands are supported. If this parameter is set to false, the disk device type is VBD, which supports only simple SCSI read/write commands.

Response¶

See Responses (Task).

Example Request¶

Attach a SCSI EVS disk to device /dev/sda.

POST https://{endpoint}/v1/{project_id}/cloudservers/{server_id}/attachvolume

{
    "volumeAttachment": {
         "volumeId": "a26887c6-c47b-4654-abb5-dfadf7d3f803",
         "device": "/dev/sda",
         "volume_type": "SSD",
         "count": 5,
         "hw:passthrough": "true"
    },
    "dry_run": false
}

Send a pre-check request for attaching a disk.

POST https://{endpoint}/v1/{project_id}/cloudservers/{server_id}/attachvolume

{
    "volumeAttachment": {
         "volumeId": "a26887c6-c47b-4654-abb5-dfadf7d3f803",
         "volume_type": "SSD",
         "count": 1,
         "hw:passthrough": "true"
    },
    "dry_run": true
}

Example Response¶

{
    "job_id": "ff80808288d41e1b018990260955686a"
}

Returned Values¶

See Returned Values for General Requests.

Error Codes¶

See Error Codes.

last updated: 2025-11-11 12:05 UTC - commit: 587a357355e02fb06d197edb7dc8df2eddcf3c8c