Files
vagrant-libvirt/spec
Holger Finger cb051a8277 specify qcow2 compatibility version to not use very old 0.10 fallback (#1731)
Libvirt creates qcow2 volumes with very old `compat` version `0.10` if
no `compat` version is specified in the xml (see
[here](https://libvirt.org/formatstorage.html#id11)). It seems libvirt
has backwards compatibility reasons to still use `0.10` if nothing is
specified in the xml.

Unfortunately this has the effect that VMs created by vagrant-libvirt
are using the 10 year old `0.10` qcow2 version, instead of the `1.1`
version that has **better performance and stability fixes**.
This is even happening when the backing file of the vagrant box is in
compat `1.1` format.

This is the `qemu-img info` of the backing file provided by the vagrant
box:
```
# qemu-img info /var/lib/libvirt/images/vagrant_box_image_0_box.img
[...]
Format specific information:
    compat: 1.1
    [...]
```
Although the backing file provided by the box is using compat `1.1`, the
created volume by vagrant-libvirt has only compat `0.1` as shown here:
```
# qemu-img info /var/lib/libvirt/images/vagrant-01-test_default.img
[...]
backing file: /var/lib/libvirt/images/vagrant_box_image_0_box.img
Format specific information:
    compat: 0.10
    [...]
```

With this MR, the volume of the VM will use the same `compat` version as
provided by the backing image of the vagrant box.
If `qemu-img info` does not return a `compat` flag, it falls back to the
very old `0.10` version.
2023-04-22 14:03:21 +01:00
..