Re: [Qemu-devel] [RFC PATCH 0/2] GlusterFS support in QEMU - v2

[ronnie sahlberg <ronniesahlberg@gmail.com>]

Stefan,

in iscsi,  i just specify those extra arguments that are required that
are not part of the url itself as just command line options :


qemu-system-i386 -iscsi initiator-name=iqn.qemu.test:my-initiator \
    -boot d -drive file=iscsi://127.0.0.1/iqn.qemu.test/1 \
    -cdrom iscsi://127.0.0.1/iqn.qemu.test/2

Here  initiator-name is a custom option to the iscsi layer to tell it
which name to use when identifying/logging in to the target.

Similar concept could be used by glusterfs ?

regards
ronnie sahlberg



On Mon, Jul 23, 2012 at 7:20 PM, Stefan Hajnoczi <stefanha@gmail.com> wrote:
> On Mon, Jul 23, 2012 at 9:50 AM, Bharata B Rao
> <bharata@linux.vnet.ibm.com> wrote:
>> On Sun, Jul 22, 2012 at 03:42:28PM +0100, Stefan Hajnoczi wrote:
>>> On Sat, Jul 21, 2012 at 9:29 AM, Bharata B Rao
>>> <bharata@linux.vnet.ibm.com> wrote:
>>> > -drive file=gluster:server@port:volname:image
>>> >
>>> > - Here 'gluster' is the protocol.
>>> > - 'server@port' specifies the server where the volume file specification for
>>> >   the given volume resides. 'port' is the port number on which gluster
>>> >   management daemon (glusterd) is listening. This is optional and if not
>>> >   specified, QEMU will send 0 which will make libgfapi to use the default
>>> >   port.
>>>
>>> 'server@port' is weird notation.  Normally it is 'server:port' (e.g.
>>> URLs).  Can you change it?
>>
>> I don't like but, but settled for it since port was optional and : was
>> being used as separator here.
>>
>>>
>>> What about the other transports supported by libgfapi: UNIX domain
>>> sockets and RDMA?  My reading of glfs.h is that there are 3 connection
>>> options:
>>> 1. 'transport': 'socket' (default), 'unix', 'rdma'
>>> 2. 'host': server hostname for 'socket', path to UNIX domain socket
>>> for 'unix', or something else for 'rdma'
>>> 3. 'port': TCP port when 'socket' is used.  Ignored otherwise.
>>>
>>> Unfortunately QEMU block drivers cannot take custom options yet.  That
>>> would make it possible to cleanly map these connection options and
>>> save you from inventing syntax which doesn't expose all options.
>>>
>>> In the meantime it would be nice if the syntax exposed all options.
>>
>> So without the capability to pass custom options to block drivers, am I forced
>> to keep extending the file= with more and more options ?
>>
>> file=gluster:transport:server:port:volname:image ?
>>
>> Looks ugly and not easy to make any particular option optional. If needed I can
>> support this from GlusterFS backend.
>
> Kevin, Markus: Any thoughts on passing options to block drivers?
> Encoding GlusterFS options into a "filename" string is pretty
> cumbersome.
>