Open Stack

On Tue, Sep 23, 2014 at 8:58 PM, Daniel P. Berrange <berrange at redhat.com> wrote:
> On Tue, Sep 23, 2014 at 02:27:52PM +0400, Roman Bogorodskiy wrote:
>>   Michael Still wrote:
>>
>> > Hi.
>> >
>> > I know we've been talking about deprecating nova.virt.disk.vfs.localfs
>> > for a long time, in favour of wanting people to use libguestfs
>> > instead. However, I can't immediately find any written documentation
>> > for when we said we'd do that thing.
>> >
>> > Additionally, this came to my attention because Ubuntu 14.04 is
>> > apparently shipping a libguestfs old enough to cause us to emit the
>> > "falling back to localfs" warning, so I think we need Ubuntu to catch
>> > up before we can do this thing.
>> >
>> > So -- how about we remove localfs early in Kilo to give Canonical a
>> > release to update libguestfs?
>> >
>> > Thoughts appreciated,
>> > Michael
>>
>> If at some point we'd start moving into getting FreeBSD supported as a
>> host OS for OpenStack, then it would make sense to keep localfs for that
>> configuration.
>>
>> libguestfs doesn't work on FreeBSD yet. On the other hand, localfs
>> code in Nova doesn't look like it'd be hard to port.
>
> Yep, that's a good point and in fact applies to Linux too when considering
> the non-KVM/QEMU drivers libvirt supports. eg if your host does not have
> virtualization and you're using LXC for container virt, then we need to
> have localfs still be present. Likewise if running Xen.
>
> So we definitely cannot delete or even deprecate it unconditionally. We
> simply want to make sure localfs isn't used when Nova is configured to
> run QEMU/KVM via libvirt.
>
> So if we take the config option approach I suggested, then we'd set a
> default value for the vfs_impl parameter according to which libvirt
> driver you have enabled.

I'm glad we've had this thread, because I hadn't thought of the
FreeBSD case at all. In that case I wonder if we want to water down
the warning we currently log in this case:

                LOG.warn(_LW("Unable to import guestfs"
                             "falling back to VFSLocalFS"))

If feel like it should be an info if we know some platforms will
always have this occur. I know this is a minor thing, but this came to
my attention because at lease one operator was concerned by seeing
that warning in their logs.

Michael

-- 
Rackspace Australia