[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] Creating / formatting volumes with non-file based block bac
Daniel P. Berrange
[Qemu-devel] Creating / formatting volumes with non-file based block backends
Wed, 11 May 2016 15:28:41 +0100
I'm looking once again at the process of creating volumes for QEMU formatted
with LUKS encryption.
For plain files it is easily possible with
qemu-img create -f luks \
--object secret,id=sec0,file=passphrase.txt \
-o key-secret=sec0 \
where 'demo.luks' is the filename to be created, mapping through to the
block driver API
int (*bdrv_create)(const char *filename, QemuOpts *opts, Error **errp);
This creates a plain file and then formats it with LUKS.
Now if I want to instead create a non-plain file (eg a glusterfs image)
and format it with LUKS, AFAICT, this is not possible since we can't
specify options / driver for the next level below the LUKS block backend,
we've only got a plain filename. I'm wondering if perhaps using the JSON
format for the 'filename' parameter value might work, but it would be
desirable to use the regular nested-opts syntax available everywhere else
in the block layer.
A second problem arises if I have an already existing volume that I wish
to merely format with luks. There's no way to skip the create step for
the block backend below the LUKS driver, as create + format are combined
into the same operation. It feels like there's a potential use case for
a separate 'qemu-img format' command which just takes a pre-existing image
and just formats a new image layout on top of it ?
Essentially I would like to be able to create a LUKS formatted image on
top of any QEMU block driver backend that supports the bdrv_create
operation. I would also like to be able to format LUKS onto any pre-existing
image for which there is a QEMU block driver backend with write support.
Any thoughts on this ? If there's clarity around design / requirements,
I have potential free time for working on this in the 2.7 cycle.
|: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org -o- http://virt-manager.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
|[Prev in Thread]
||[Next in Thread]|
- [Qemu-devel] Creating / formatting volumes with non-file based block backends,
Daniel P. Berrange <=