[ovirt-users] Ovirt python-sdk cloning VM
Juan Hernández
jhernand at redhat.com
Mon Jan 18 15:34:07 UTC 2016
On 01/18/2016 02:49 PM, Algirdas Žemaitis wrote:
> Hello,
>
>
> I was playing with Ovirt API/python-sdk for a week or so and stuck in
> one from first sight simple yet unsolvable spot…
>
> Ovirt web GUI has option to clone VM from snapshot, to new(other)
> storage domain. Is it possible to do so with API ?
>
> The point is, I’m using backup script (already modified a lot of it to
> suit our needs), once it is cloning from snapshot into new VM, it will
> use same storage, and causing a lot of load on already stressed domain,
> idea is to create VM (allocate disk before exporting it as backup) on
> other storage domain, in this way significantly reducing impact on live
> storage domain. What do you think ?
>
> Original : https://github.com/wefixit-AT/oVirtBackup
>
>
>
> Thank you for your time, and sorry for reaching directly, Ovirt lacks
> for an forum or something similar… or I just couldn’t find it…
>
I'm adding the users at ovirt.org list, there is where you can send your
questions.
In order to clone a VM from an snapshot you have to use the "add"
operation of the "vms" service, passing as a parameter a "vm" object
that contains the identifier of the snapshot and the explicit mapping of
disk to storage domain. In XML it should look like this:
---8<---
<vm>
<name>myclone</name>
<cluster>
<name>mycluster</name>
</cluster>
<!-- This is how you indicate what snapshot to clone: -->
<snapshots>
<snapshot id="266742a5-6a65-483c-816d-d2ce49746680"/>
</snapshots>
<!-- This is how you indicate how to map disks to storage
domains. -->
<disks>
<disk>
<image_id>8d4bd566-6c86-4592-a4a7-912dbf93c298</image_id>
<storage_domains>
<storage_domain id="9cb6cb0a-cf1d-41c2-92ca-5a6d665649c9"/>
</storage_domains>
</disk>
</disks>
</vm>
--->8---
With the Python SDK it should look like this:
---8<---
# Find the VM:
vm = api.vms.get(name="myvm")
# Find the snapshot:
snapshot = None
for current in vm.snapshots.list():
if current.get_description() == 'mysnap':
snapshot = current
break # Should probably end here, with an error.
# Find the image identifiers of the disks of the snapshot, as
# we need them in order to explicitly indicate that we want
# them created in a different storage domain:
disk_ids = []
for current in snapshot.disks.list():
disk_ids.append(current.get_id())
# Find the storage domain where the disks should be created:
sd = api.storagedomains.get(name="yourdata")
# Prepare the list of disks for the operation to create the
# snapshot,explicitly indicating for each of them the storage
# domain where it should be created:
disk_list = []
for disk_id in disk_ids:
disk = params.Disk(
image_id=disk_id,
storage_domains=params.StorageDomains(
storage_domain=[
params.StorageDomain(
id=sd.get_id(),
),
],
),
)
disk_list.append(disk)
# Create the VM from the snapshot:
api.vms.add(
params.VM(
name="myclone",
cluster=params.Cluster(name="mycluster"),
snapshots=params.Snapshots(
snapshot=[
params.Snapshot(
id=snapshot.get_id(),
),
],
),
disks=params.Disks(
disk=disk_list,
),
)
)
--->8---
This should work for you.
However, I have to say that I find a bit strange that we use the
"image_id" attribute as the key of the disk in this case, instead of
just the "id". Allon, do you know if this is on purpose? I mean, when we
clone a VM from a template we use do like this:
<disk id="the_key">
...
</disk>
But in this case we do like this:
<disk>
<image_id>the_key</image_id>
...
</disk>
Is there any reason for these two different ways to specify the
identifier of the disk?
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