[pve-devel] kvm disk template implementation ideas

[Dietmar Maurer]

> -----Original Message-----
> From: pve-devel-bounces at pve.proxmox.com [mailto:pve-devel-
> bounces at pve.proxmox.com] On Behalf Of Alexandre DERUMIER
> Sent: Mittwoch, 22. August 2012 09:49
> To: pve-devel at pve.proxmox.com
> Subject: [pve-devel] kvm disk template implementation ideas
> 
> Hi,
> one feature that really miss on proxmox currently is disk templates for kvm
> machines.
> I'm currently doing it with custom scripts, but I would like to add clean
> implementation in proxmox in the coming months(I think users should be
> happy too :)
> 
> I don't know if you have already thinked about it, but here some ideas:
> 
> template feature with image copy from source (file storage, .raw files) to
> destination.
> ---------------------------------------------------------------------------------------
> for each storage module, add an export and import sub.
> 
> import:
> ------
> import is used to import existing template in the target storage
> 
> file,nfs: cp /var/lib/vz/template/qemu/template1.raw  /mnt/myimage.raw
> lvm :  dd if=/var/lib/vz/template/qemu/template1.raw of=/dev/lvm/..
> iscsi : dd if=/var/lib/vz/template/qemu/template1.raw of=/dev/sd rbd :  rbd
> import /var/lib/vz/template/qemu/template1.raw  myrbdimage
> sheepdog: cat /var/lib/vz/template/qemu/template1.raw | collie vdi write
> mysheepimage libiscsi,nexenta : LD_PRELOAD=./bin/ld_iscsi.so dd
> if=/var/lib/vz/template/qemu/template1.raw
> of=iscsi://127.0.0.1:3262/iqn.ronnie.test/2
> 
> export:
> --------
> export is used to export a disk to the template storage, for creating new
> templates
> 
> file,nfs: cp /mnt/myimage.raw /var/lib/vz/template/qemu/template1.raw
> lvm :  dd if=/dev/lvm/.. of=/var/lib/vz/template/qemu/template1.raw
> iscsi : dd if=/dev/sd of=/var/lib/vz/template/qemu/template1.raw
> rbd :  rbd export myrbdimage /var/lib/vz/template/qemu/template1.raw
> sheepdog: collie vdi read mysheepimage >
> /var/lib/vz/template/qemu/template1.raw
> libiscsi,nexenta : LD_PRELOAD=./bin/ld_iscsi.so dd
> if=iscsi://127.0.0.1:3262/iqn.ronnie.test/2
> of=/var/lib/vz/template/qemu/template1.raw
> 
> then add some kind of
> qm exportdisk <vmid> <disk> <target>        : qm exportdisk vmid virtio0
> /var/lib/vz/template/qemu/template1.raw
> qm importdisk <vmid> <disk> <source>        : qm importdisk vmid virtio0
> /var/lib/vz/template/qemu/template1.raw
> 
> or maybe can we integrate this in vzdump/vzrestore.
> So we could also make backup/restore for all storages.
> I never look in vzdump code, so I don't know how it's work
> 
> 
> 
> template feature with image cloning
> -----------------------------------
> for storage which support it, add a template feature based on image
> snapshot/instant cloning.
> currently nexenta,sheepdog and rbd(soon), lvm??? support it.
> 
> I don't know really how to implement this, as we need to see difference
> between vm disk and templates disk.
> (And we can't have a template directory).
> we can't rename volume rbd,sheepdog so maybe can we allow snapshot
> named "template-..."
> 
> for this features, we need to add storage sub:
> 
> snapshot_create, clone, disktemplate_list (like vdisk_list)
> 
> 
> snapshot_create
> ----------------
> rbd:  snap create --snap template-template1 vm-id-disk-1
> sheepdog:  collie vdi snapshot -s template-template1 vm-id-disk-1 nexenta :
> nexenta api snap vm-id-disk-1 at template-template1
> 
> 
> disktemplate_list (return list of templates(snapshots) and associated disk
> ----------------------------------------------------------------------------
> sheepdog : collie vdi list
> rbd : problem : can't easilly list all templates, without calling "rbd snap ls
> image1" for each image
> nexenta: nexenta api to list templates
> 
> another solution is to maintain a list of snapshots in a text file or somewhere
> else, but we don't like that in proxmox.
> 
> clone
> -----
> 
> rbd: coming soon
> sheepdog:  collie vdi clone -s template-template1 vm-id-disk-1
> mytargetimage nexenta : nexenta clone api vm-id-disk-1 at template-
> template1 mytargetimage
> 
> 
> 
> then add some kind of
> qm clonedisk <vmid> <disk> <template>        : qm clonedisk vmid virtio0
> template-template1
> 
> 
> 
> 
> What do you think about it ? Don't hesitate to comments.
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