I am also thinking to add a centralized area in header to hold all asynchronous tasks. On 10/3/2014 2:05 AM, Crístian Viana wrote:
Hi everyone,
I'm presenting here my proposal for the feature "Guest cloning" which is expected to be implemented for Kimchi 1.4.
Description
Cloning a guest means creating a new guest with a copy of the settings and data of the original guest. All data described by its XML will be copied completely, with the following exceptions:
* name: the new guest will have an automatically generated name. We can append "-clone<n>" to the original guest's name, where <n> is related to the number of clones created from that guest. For example, cloning a guest named "myfedora" will create a new guest named "myfedora-clone1"; if another clone for that same guest is requested, it will be named "myfedora-clone2". * uuid: the new guest will have an automatically generated UUID. We can create a random UUID for every cloned guest. * devices/interface/mac: the new guest will have an automatically generated MAC address for every network interface. We can create random MAC addresses for every cloned guest. * devices/disk: the new guest will have copies of the original guest's disks. Depending on the storage pool type of each disk, a different procedure may be used to copy that disk:
* DIR, NFS, Logical: the disk file will be copied to a new file with a modified name (e.g. "disk.img" -> "disk-clone1.img") on the same storage pool. * SCSI, iSCSI: the volume data will be copied as a new disk file on the storage pool "default".
REST API
Only one new REST command will be added.
Syntax
POST /vms//<vm-name>//clone
Parameters:
None.
Return:
An asynchronous Task with "target_uri" containing "/vms/</new-vm-name/>". As expected with any Task, the cloning process can be tracked by checking the corresponding task's status.
Discussion
I think the most challenging part of this feature is how to deal with different types of disks while not prompting the user with any input. There are a lot of possibilities and a lot of things that can go wrong during the disks copy but we still need to do whatever is easier for the user. For example, do we really have to create the new disks in the same storage pool as the original disk's? If that's not possible (e.g. not available space), should we create them in another pool with available space? Should we ask any input from the user (e.g. "Would you like to create the new disk on the same storage pool or on a different one?")? What about the *SCSI pool types, is it OK to copy the volume data to a different storage pool (i.e. "default") like I'm proposing here? I couldn't think of a way to add a new volume in an existing pool of those types. How about making the *SCSI volumes shareable between the original and the new VMs? I don't like that approach because then both VMs will use the same disk, whatever is changed in one VM is also changed in the other one, and that's not a clone for me, that's a "hardlink".
Any feedback is welcome!
Best regards, Crístian.
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