Re: [Engine-devel] [vdsm] FW: Querying for and registering unknown disk images on a storage domain

2012-12-20 23:18, Morrissey, Christopher: > > Hi All, > > I’ve been working on a bit of functionality for the engine that will > allow a user to query a domain for new disk images > (GetUnregisteredImagesQuery) for which the engine was previously > unaware and a separate command to register those images > (ImportImageCommand). These commands will be exposed through the REST API. > > This functionality is needed as we are developing an extension/plugin > to oVirt that will allow a NetApp storage controller to handle cloning > the actual disks outside of oVirt and need to import them once they > are cloned. We’ll be using other existing APIs to attach the disk to > the necessary VM once the disk is cloned. On the NetApp side, we’ll > ensure the disk is coalesced before cloning so as to avoid the issues > of registering snapshots. > I am just curious about how the third party tool like NetApp to make sure the disk of a running VM coalesced before cloning? By an agent in the VM to flush file-system cache out to the disk?

> GetUnregisteredImagesQuery will be accessible through the disks > resource collection on a storage domain. A “disks” resource collection > does not yet exist and will need to be added. To access the > unregistered images, a parameter (maybe “unregistered=true”) would be > passed. So the path to “GET” the unregistered disk images on a domain > would be something like > /api/storagedomains/f0dbcb33-69d3-4899-9352-8e8a02f01bbd/disks?unregistered=true. > This will return a list of disk images that can be each used as input > to the ImportImageCommand to get them added to oVirt. > > ImportImageCommand will be accessible through “POST”ing a disk to > /api/disks?import=true. The disk will be added to the oVirt DB based > on the information supplied and afterward would be available to attach > to a VM. > > When querying for unregistered disk images, the > GetUnregisteredImagesQuery command will use the getImagesList() VDSM > command. Currently this only reports the GUIDs of all disk images in a > domain. I had been using the getVolumesList() and getVolumeInfo() VDSM > commands to fill in the information so that valid disk image objects > could be registered in oVirt. It seems these two functions are set to > be removed since they are too invasive into the internal VDSM > workings. The VDSM team will need to either return more information > about each disk as part of the getImagesList() function or add a new > function getImageInfo() that will give the same information for a > given image GUID. > Here is the project proposal for floating disk in oVirt. I think unregistered images are also floating disks. http://www.ovirt.org/Features/DetailedFloatingDisk