[ovirt-users] Re: OVA export creates empty and unusable images

On Thu, Jul 30, 2020 at 5:10 PM <thomas(a)hoberg.net&gt; wrote: 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... [3] https://github.com/oVirt/ovirt-engine-sdk/blob/master/sdk/examples/upload... [4] https://www.youtube.com/watch?v=foyi1UyadEc