On 04/24/2018 09:01 AM, Drew White wrote:
> On Tuesday, 24 April 2018 15:28:40 UTC+10, Ivan Mitev wrote:
>> On 04/24/2018 08:14 AM, Drew White wrote:
>>> Is it possible for every guest to share one virtual drive for cacheing and auto mounting to same location for file transfers?
>>
>> It isn't possible unless you set up a clustered file system, which
>> implies having in-band or out-of-band communication channels between
>> guests. This breaks compartmentalization, which is Qubes' raison d'etre,
>> so if you really need this you're better off ditching Qubes and go with
>> plain kvm (or xen) VMs.
>>
>
> I'm not talking about for all guests. and the channel would be one image file, read only. Writable only by one guest that does the downloading securely and checks and writes the files.
AFAIK it's not possible. You need a clustered FS to see changes in real
time; If you share an image/device you'll have to
- make sure the guest with write rights has fsync'ed the changes to the
FS and/or that no cache is involved.
- unmount/remount the shared volume in R/O guests each time you need to
read new files.
I have no idea if Qubes allows sharing a volume between guests; I'd
imagine that qvm-* commands won't allow that so that users don't shoot
themselves in the foot, but you may be able to achieve this with lower
level commands or by tweaking the qvm-* commands' source.
But since you're sending content from a VM to other guests, the security
level of your R/O guests is basically dependent on the one you download
files to, so you could open some firewall ports and setup a networked
clustered FS like glusterfs.