This API is used to attach EVS disks to a BMS as data disks after the BMS is created if existing disks are insufficient or cannot meet requirements.

EVS disks cannot be attached to a BMS in a batch.
A maximum of 40 EVS disks can be attached to a BMS.
A bootable disk cannot be attached to a BMS.
A disk cannot be attached to a BMS in the PAUSED state. The state is indicated by the OS-EXT-STS:vm_state parameter.
Only a shared disk or a disk in the available state can be attached to a BMS.
Only EVS disks whose device type is SCSI can be attached to a BMS.

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

Table 1 lists the parameters.

**Table 1** Parameter description
Parameter	Mandatory	Description
project_id	Yes	Specifies the project ID. For details about how to obtain the project ID, see Obtaining a Project ID.
server_id	Yes	Specifies the BMS ID. You can obtain the BMS ID from the BMS console or by calling the Querying BMSs (Native OpenStack API).

Request parameters

Parameter	Mandatory	Type	Description
volumeAttachment	Yes	Object	Specifies the disks to be attached. For details, see Table 2.

**Table 2** **volumeAttachment** field data structure description
Parameter	Mandatory	Type	Description
volumeId	Yes	String	Specifies the ID of the disk to be attached to a BMS. You can obtain the disk ID from the EVS console or by calling the "Querying EVS Disks" API in Elastic Volume Service API Reference.
device	No	String	Specifies the mount point, such as /dev/sda and /dev/sdb. The new disk mount point cannot be the same as an existing one. The mount point must be specified based on the sequence of existing device names. If this parameter is left blank or set to "", the system automatically generates a mount point.

Example request

POST https://{BMS Endpoint}/v1/bbf1946d374b44a0a2a95533562ba954/baremetalservers/cf2a8b97-b5c6-47ef-9714-eb27adf26e5b/attachvolume

{
    "volumeAttachment": {
        "volumeId": "b53f23bd-ee8f-49ec-9420-d1acfeaf91d6",
        "device": ""
    }
}

**Table 3** Normal response
Parameter	Type	Description
job_id	String	Specifies the task ID returned after a task command is issued. The task ID can be used to query the execution status of the task. For details about how to query the task execution status based on job_id, see Querying Task Statuses.

**Table 4** Abnormal response
Parameter	Type	Description
error	Dictionary data structure	Specifies the error returned when a task submission encounters an exception. For details, see Table 5.

**Table 5** **error** data structure
Parameter	Type	Description
message	String	Specifies the error message.
code	String	Specifies the error code.

Normal response

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

Normal values

Returned Value	Description
202	The request has been accepted, but the processing has been delayed.

For details about other returned values, see Status Codes.

Attaching an EVS Disk to a BMS