Transfer share between project

Add support for share transfer that allows a user to transfer a share to another user under other project, just like cinder transfer-create, transfer-accept, transfer-delete. There are two scenarios, the first is DHSS=False, the second is DHSS=True. In the first scenario, will only support transferring shares that are not tied to a share network. The object of the transfer is Share. In the second scenario, we would support transferring share networks, which would cause all of its shares to be migrated within. This will be completed in another spec.

Problem Description

In an actual OpenStack production environment, it is common for a user to transfer a storage resource to another user for collaborative pipeline work. Manila Share also needs a secure way to transfer shares so that other users can receive them safely.

Use Cases

  • The user in project A pre-populate data for another user in project B.

  • When a project is “ending”/being decommissioned, share data can be transferred to a project that’s still needed.

  • Transfer share to specific user to collaborate on the rest of the work.

Proposed Change

This spec proposes to:

  • Add a new table, which named transfers. Includes the following fields:

    • id the primary key of table.

    • resource_type the type of resource which is being transferred, this can be share, share network and so on.

    • resource_id the uuid of resource which is being transferred.

    • name the display name of transfer.

    • salt a short random string used to calculate crypt_hash, after create transfer will return auth_key(also a short random string), salt and auth_key calculate crypt_hash by sha1.

    • crypt_hash the hash value for transfer.

    • expires_at the expire time of transfer, one hour(default) later after created.

    • source_project_id the source project id of share.

    • destination_project_id the destination project id of share.

    • accepted whether the share has been accepted.

  • Add a new status awaiting_transfer for shares, which is being transferred.

  • Check the following before create share transfer:

    • check the status of share and share_snapshot and share_replica before create transfer, share and all share_snapshot must be available.

    • check whether the share in share group, share cannot be in a share group.

    • check whether share has share network, this spec just supports the first scenario (DHSS=False), share without share network will allowed to be transferred.

  • Check the following before accept transfer:

    • check quota of destination project, include project quota, project user quota, project share type quota, per_share_gigabytes, make sure destination project has enough remaining quota.

    • if the share type of source share is not public, and the share type access of share type does not include the destination project, it will fail to accept transfer.

  • For security reasons, a share transfer will be cancelled automatically if it is not accepted one hour(default) after creation. There will be a periodic task that checks for expire transfers every 5 minutes.

  • Add a new configure item wait_transfer_timeout_seconds, default is 3600 seconds.

  • “transfer-accept” need to call driver to complete project_id change, such as CephFS driver stores the project_id as metadata. The parent class driver only defines the function, but does not implement it.

  • When accepting a transfer, users can choose whether need to clear the share access rule. By default, the share access rule will not be cleared.

  • Add new API for transfer-create, transfer-accept, transfer-delete, transfer- list, transfer-show.

  • The above API changes will bump a new microversion.


  • An alternative here is manage/unamanage, a share in Project A can be “unmanaged” by a privileged user and “managed” into another project. However two issues with that approach:

    • manage/unmanage is meant to be disruptive - pre-existing access rules will be flushed and the share would be re-exported.

    • you’d need to be a privileged user by virtue of the default RBAC because this approach gives away some of teh abstraction of the cloud.

Data model impact

  • A new table transfers will be added.

REST API impact

  • Create a share transfer

POST /v2/share-transfers

Request Example:

        "share_id": "da8eb12e-123c-49ea-ae2b-5d42f02fa00e",
        "name": "share transfer"

Response Example:

        "auth_key": "qbgcabtdbad29r08",
        "created_at": "2021-12-27T11:29:46.743632",
        "name": "share transfer",
        "share_id": "da8eb12e-123c-49ea-ae2b-5d42f02fa00e",

auth_key is necessary in accept share transfer, please keep records properly, since it cannot be retrieved later on.

  • Accept a share transfer

POST /v2/share-transfers/{transfer_id}/accept

Request Example:

        "auth_key": "6461646164641397",
        "clear_access_rules": "false",
  • List share transfers for a project

GET /v2/share-transfers

  • List share transfers and details

GET /v2/share-transfers/detail

  • Show share transfer detail

GET /v2/share-transfers/{transfer_id}

  • Delete share transfer

DELETE /v2/share-transfers/{transfer_id}

Security impact

  • Each of these transfer APIs will be protected by RBAC.

  • Users can only transfer shares belonging to their project.

  • The transfer ID and transfer auth key are expected to be conveyed out of band. The transfer auth key is only returned by the API during creation of a transfer. There will be no way to retrieve the transfer auth key after a transfer has been created.

  • the choice of cryptographic algorithms to generate an auth_key and the fact that transfer IDs are non-guessable UUIDs will provide additional security to the process.

  • Since transfers expire in an hour(default), there’s a time bound protection to this critical change of namespaces.

Notifications impact

We must notify to external listeners when a volume transfer has been initiated and when it has been accepted.

Other end user impact

The Manila client, CLI will be extended to support share transfer.

  • The command of create share transfer will be like:

    openstack share transfer create <share>
  • The command of accept share transfer will be like:

    openstack share transfer accept [--clear-rules] <transfer> <auth_key>
  • The command of list share transfer will be like:

    openstack share transfer list
  • The command of show share transfer detail will be like:

    openstack share transfer show <transfer>
  • The command of delete share transfer will be like:

    openstack share transfer delete <transfer>

Performance Impact


Other deployer impact


Developer impact

Drivers that use project and user based metadata must implement the new driver interface to complete “transfer_accept”.



Primary assignee:

haixin <>

Work Items

  • Update API.

  • Update Database

  • Update Manager.

  • Update Manila CLI commands.

  • Update unit and tempest test.

  • Update related documents.

  • Update Manila UI.




  • Add the unit tests

  • Add the tempest tests

Documentation Impact

The following OpenStack documentations will be updated to reflect this change:

  • OpenStack User Guide

  • OpenStack Contributor Guide

  • OpenStack API Reference


Based on cinder transfer strategy. Includes the following: