On Thu, Jul 30, 2020 at 5:10 PM <tho...@hoberg.net> wrote:
>
> Export/Import/Transfer via export domain worked just fine. Just moved my last 
> surviving Univention domain controller from the single node HCI 
> disaster-recovery farm to the three node HCI primary, where I can now try to 
> make it primary and start building new backups...
>
> Backups that do not work are food for nightmares!

OVA export/import[1]  is not a backup solution. This is a way to move
a VM from one
environment to another. For this we have a much better way, detach
data domain and import it
in another environment.

If 4.4 we have a real backup API (tech preview). This will be used by
backup vendors to provide
complete backup solution, but we have basic backup capabilities
included in the sdk examples.
See the devconf 2020 talk[4] for more info.

The examples deal only with backing up and restoring disks. Getting
the vm configuration and
creating a vm from the configuration is not included yet.

Here is how you can do full back of a running vm disks using
backup_vm.py[2] example:

$ ./backup_vm.py full --engine-url https://engine3 \
    --username admin@internal \
    --password-file engine3-password \
    --cafile engine3.pem \
    --backup-dir backups \
    ed2e2c59-36d3-41e2-ac7e-f4d33eb69ad4
[   0.0 ] Starting full backup for VM ed2e2c59-36d3-41e2-ac7e-f4d33eb69ad4
[   1.7 ] Waiting until backup 4ac0ae37-b1dd-4a8d-ad13-1ddb51e70d3e is ready
[   3.8 ] Created checkpoint '3648484c-61dc-4680-a7b4-0256544fa21d'
(to use in --from-checkpoint-uuid for the next incremental backup)
[   3.8 ] Creating image transfer for disk 419b83e7-a6b5-4445-9324-a85e27b134d2
[   5.1 ] Image transfer c659437e-6242-42b9-9293-8ccf10321261 is ready
Formatting 
'backups/419b83e7-a6b5-4445-9324-a85e27b134d2.202008011652.full.qcow2',
fmt=qcow2 size=107374182400 cluster_size=65536 lazy_refcounts=off
refcount_bits=16
[ 100.00% ] 100.00 GiB, 0.39 seconds, 258.06 GiB/s
[   5.5 ] Finalizing image transfer
[   7.5 ] Creating image transfer for disk 58daea80-1229-4c6b-b33c-1a4e568c8ad7
[   8.7 ] Image transfer 78254cef-5f22-4161-8dbd-010420730a7f is ready
Formatting 
'backups/58daea80-1229-4c6b-b33c-1a4e568c8ad7.202008011652.full.qcow2',
fmt=qcow2 size=6442450944 cluster_size=65536 lazy_refcounts=off
refcount_bits=16
[ 100.00% ] 6.00 GiB, 10.33 seconds, 594.54 MiB/s
[  19.0 ] Finalizing image transfer
[  23.3 ] Full backup completed successfully

Note that we did not create any snapshot, backup provides a consistent
view on all disks
at the time of the backup, but you must have qemu-guest-agent
installed in the VM. This is
the same consistency you get from snapshot without memory.

$ ls -lh backups/
total 2.3G
-rw-r--r--. 1 nsoffer nsoffer  52M Aug  1 16:52
419b83e7-a6b5-4445-9324-a85e27b134d2.202008011652.full.qcow2
-rw-r--r--. 1 nsoffer nsoffer 2.2G Aug  1 16:52
58daea80-1229-4c6b-b33c-1a4e568c8ad7.202008011652.full.qcow2

In this example we detected that the 100 GiB disk
419b83e7-a6b5-4445-9324-a85e27b134d2.202008011652
is mostly empty (mounted file system, no data written yet) so we could
download only the allocated blocks.

$ qemu-img info
backups/419b83e7-a6b5-4445-9324-a85e27b134d2.202008011652.full.qcow2
image: backups/419b83e7-a6b5-4445-9324-a85e27b134d2.202008011652.full.qcow2
file format: qcow2
virtual size: 100 GiB (107374182400 bytes)
disk size: 51 MiB
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: false
    refcount bits: 16
    corrupt: false

The second disk is a Fedora 32 OS disk, so we downloaded only the
allocated blocks, about 2.2 GiB.

$ qemu-img info
backups/58daea80-1229-4c6b-b33c-1a4e568c8ad7.202008011652.full.qcow2
image: backups/58daea80-1229-4c6b-b33c-1a4e568c8ad7.202008011652.full.qcow2
file format: qcow2
virtual size: 6 GiB (6442450944 bytes)
disk size: 2.17 GiB
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: false
    refcount bits: 16
    corrupt: false

To restore the disks you can use upload_disk.py[3] example:

$ ./upload_disk.py --engine-url https://engine3 \
    --username admin@internal \
    --password-file engine3-password \
    --cafile engine3.pem \
    --sd-name nfs1 \
    --disk-format raw \
    --disk-sparse \
    backups/419b83e7-a6b5-4445-9324-a85e27b134d2.202008011652.full.qcow2
Checking image...
Image format: qcow2
Disk format: raw
Disk content type: data
Disk provisioned size: 107374182400
Disk initial size: 107374182400
Disk name: 419b83e7-a6b5-4445-9324-a85e27b134d2.202008011652.full.raw
Disk backup: False
Connecting...
Creating disk...
Disk ID: 5c9465d6-6437-4ece-bcaa-eec6b2d00a9d
Creating image transfer...
Transfer ID: dfcce09b-1f65-45e6-8ea5-41dff9368b15
Transfer host name: host4
Uploading image...
[ 100.00% ] 100.00 GiB, 0.75 seconds, 133.31 GiB/s
Finalizing image transfer...
Upload completed successfully

Again we upload only the allocated blocks, so the upload is very quick.

Note that we upload the qcow2 disk to raw sparse disk. We support
on-the-fly image format
conversion.

$ ./upload_disk.py --engine-url https://engine3 \
    --username admin@internal \
    --password-file engine3-password \
    --cafile engine3.pem \
    --sd-name nfs1 \
    --disk-format qcow2 \
    --disk-sparse \
    backups/58daea80-1229-4c6b-b33c-1a4e568c8ad7.202008011652.full.qcow2
Checking image...
Image format: qcow2
Disk format: cow
Disk content type: data
Disk provisioned size: 6442450944
Disk initial size: 2332491776
Disk name: 58daea80-1229-4c6b-b33c-1a4e568c8ad7.202008011652.full.qcow2
Disk backup: False
Connecting...
Creating disk...
Disk ID: 5cf45aa6-6825-4aa5-adf1-4eb70809c37f
Creating image transfer...
Transfer ID: ed4046c3-63f9-445b-895b-e964dbcfc134
Transfer host name: host4
Uploading image...
[ 100.00% ] 6.00 GiB, 5.62 seconds, 1.07 GiB/s
Finalizing image transfer...
Upload completed successfully

This time we uploaded to a qcow2 format.

You can create a new vm from these disks with the same configuration
of the previous vm.
I hope that future versions will backup and restore complete vms.

This also supports incremental backups, but it is not suitable for
production, there are too
many rough edges that need to be smoothed.

We also support uploading disks from ova file. Lets create one with
compressed qcow2
format. This creates smaller ova files optimized for transfering to
other machines.

$ mkdir ova
$ qemu-img convert -f qcow2 -O qcow2 -c
backups/58daea80-1229-4c6b-b33c-1a4e568c8ad7.202008011652.full.qcow2
ova/disk1.qcow2
$ qemu-img convert -f qcow2 -O qcow2 -c
backups/419b83e7-a6b5-4445-9324-a85e27b134d2.202008011652.full.qcow2
ova/disk2.qcow2
$ ls -lh ova
total 1.3G
-rw-r--r--. 1 nsoffer nsoffer 1.3G Aug  1 17:20 disk1.qcow2
-rw-r--r--. 1 nsoffer nsoffer 576K Aug  1 17:20 disk2.qcow2
$ echo "this is not a real ovf" > ova/vm.ovf
$ tar cvf test.ova -C ova vm.ovf disk1.qcow2 disk2.qcow2
vm.ovf
disk1.qcow2
disk2.qcow2
$ ls -lhs test.ova
1.3G -rw-rw-r--. 1 nsoffer nsoffer 1.3G Aug  1 17:24 test.ova

This is not a valid ovf, but good enough to show the upload capability:

$ for disk in disk1.qcow2 disk2.qcow2; do
    ./upload_from_ova.py --engine-url https://engine3 \
        --username admin@internal \
        --password-file engine3-password \
        --cafile engine3.pem \
        --sd-name nfs1 \
        --disk-format raw \
        --disk-sparse \
        --ova-disk-name $disk \
        test.ova
done
Checking image...
Image format: qcow2
Disk name: disk1.raw
Disk format: raw
Disk provisioned size: 6442450944
Disk initial size: None
Disk backup: None
Creating disk...
Disk ID: acb7bc75-f6e9-49c8-a158-d7d581c108b4
Creating image transfer...
Transfer ID: fca2d537-0f91-4033-8b35-ef0084191b4e
Transfer host name: host4
Uploading disk disk1.qcow2 from test.ova...
[ 100.00% ] 6.00 GiB, 6.88 seconds, 893.04 MiB/s
Finalizing image transfer...
Upload completed successfully
Checking image...
Image format: qcow2
Disk name: disk2.raw
Disk format: raw
Disk provisioned size: 107374182400
Disk initial size: None
Disk backup: None
Creating disk...
Disk ID: ec57e31a-a531-48c2-8447-6468087bb4ab
Creating image transfer...
Transfer ID: 3aa23287-6ec4-4571-8623-7724c4a36341
Transfer host name: host4
Uploading disk disk2.qcow2 from test.ova...
[ 100.00% ] 100.00 GiB, 0.49 seconds, 204.34 GiB/s
Finalizing image transfer...
Upload completed successfully

To try this you need to install python3-ovirt-enigne-sdk4. The
examples scripts are in:
/usr/share/doc/python3-ovirt-engine-sdk4/examples/

We have automated tests using the upload/download/backup example
scripts, so they should
work.

Nir

[1] https://www.youtube.com/watch?v=VtuwWL6SMYk
[2] 
https://github.com/oVirt/ovirt-engine-sdk/blob/master/sdk/examples/backup_vm.py
[3] 
https://github.com/oVirt/ovirt-engine-sdk/blob/master/sdk/examples/upload_disk.py
[4] https://www.youtube.com/watch?v=foyi1UyadEc
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