Attachment info upon Get/List

[akutz]

Hi,

When inspecting a volume (VMDK) using the vmdk driver's Get or List functions, it would be fantastic if the device(s) to which that VMDK is attached is/are included in the returned information.

Upon attaching a VMDK to a VM, the device to which the VMDK is attached is returned: {"ControllerPciSlotNumber": "192", "Unit": "0"}. However, this information is not currently available for a VMDK after the initial attach call. The result is there's no way to map a VMDK to the device to which it's attached after the initial attach operation.

@msterin and I discussed storing the above information in the VMDK's associated metadata file and then removing said info upon a detach. The vol_info function would then be updated to retrieve this information as part of a standard Get or List operation.

While you're at it, it would also be wonderful if the Get/List operations would retrieve a VM's MoRef assuming that's available easily on the backend. This would enable the use of GoVmomi or any other tool to act upon the VM and its disks.

Thank you.

[msterin]

@akutz - can you add a couple of words or a link to explain how it will be used ? I understand it's something in Rex/Ray , but what is it ? It would help a lot if we understood the use case better.

[akutz]

Hi @msterin,

Sure thing. I am going to submit a PR for it soon anyway, but I don't mind expounding a bit on its purpose.

Essentially we need to be able to map a VMDK to the device to which it's attached on a VM. While the attach call provided that information at the time of the attach operation, that information is not available at any other time, such as when a VMDK is introspected via the vmdkops service.

We use this information to provide details about a volume's status and to which instance (client/node/VM) the volume is currently attached.