Hyper-V: Support for attaching volumes via SMB

https://blueprints.launchpad.net/nova/+spec/hyper-v-smbfs-volume-support

Currently, the Hyper-V driver allows attaching volumes only via iSCSI. The purpose of this blueprint is adding support for attaching volumes hosted on a SMB share.

Problem description

For the moment, there are drivers which support distributed file systems such as Gluster or NFS as volume backends. SMB is another widely used protocol, especially in the Microsoft world.

Its simplicity along with the big improvements that were introduced in SMB 3 make this type of volume backend a very good alternative.

SMB 3 brings features such as transparent failover, multichanneling using multiple NICs, encrypted communication, and RDMA. Note that in order to use live migration, SMB 3 is required.

This feature will be backwards compatible, supporting older versions of SMB for simple tasks. It will support using any type of SMB share, including:

  • from Scale-Out file servers to basic Windows shares;

  • Linux SMB shares using Samba;

  • vendor specific hardware exporting SMB shares.

Use Cases

Deployer will be able to attach to instances block storage volumes exported as virtual disks on SMB shares.

Project Priority

None

Proposed change

A new volume driver will be added in order to support attaching volumes hosted on SMB shares. The Hyper-V driver will be able to choose between the volume drivers using the volume type stored in the connection info.

The SMB volume driver will mount the share on which a volume is hosted using credentials specified in the volume connection info, then attach the volume to a VM using its UNC path. This way, the Hyper-V driver will be able to attach vhd or vhdx images hosted on SMB shares.

Alternatives

None

Data model impact

None

REST API impact

None

Security impact

The credentials recieved in the volume connection_info will be used in order to mount the according SMB share.

Note that the Hyper-V VMMS user account needs access to the remote image file in order to be able to attach it to instances. As a best practice, the Cinder and Nova nodes should be part of the same AD domain, using AD credentials and giving the required permissions to Hyper-V VMMS.

Notifications impact

None

Other end user impact

None

Performance Impact

None

Other deployer impact

None

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

<lpetrut@cloudbasesolutions.com>

Other contributors:

<gsamfira@cloudbasesolutions.com>

Work Items

Add SMB Volume driver.

Adapt Hyper-V Driver in order to be able to use multiple volume drivers according to volume types.

Adapt existing volume related operations such as lookups in order to support disk resources stored on SMB shares.

Dependencies

None

Testing

This feature should be tested along with the upcoming SMB Cinder driver. CI testing will be performed by the Hyper-V CI.

Documentation Impact

Using the SMB backend will be documented.