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Detaches disk from the VM.

If the persistent disk is attached to a VM that will be deleted, it is more likely that the delete_vm CPI method will be called without a call to detach_disk. The expectation here is that delete_vm will make sure the disks are disassociated from the VM upon its deletion.

Agent settings must have been updated to remove information about the given disk.


  • vm_cid [String]: Cloud ID of the VM.
  • disk_cid [String]: Cloud ID of the disk.


No return value


API request

  "method": "detach_disk",
  "arguments": [
  "context": {
     "director_uuid": "<director-uuid>",
    "request_id": "<cpi-request-id>",
    "vm": {
      "stemcell": {
        "api_version": 2
  "api_version": 2

API response

  "result": true,
  "error": null,
  "log": ""


Changes for V2 of the API contract

The signature for detach_disk is the same as in V1 of the API contract. For CPIs that previously used the registry to track mount points, V2 does not necessarily use the registry. The registry should be used if the stemcell API version is not sufficient. Without the registry, the Agent receives a message from the Director to remove the persistent disk from its settings. See CPI V2 Migration Guide for more information.