Re: [Qemu-devel] [PATCH v3] block: Add support for Secure Shell (ssh) block device.

[Anthony Liguori <anthony@codemonkey.ws>]

"Richard W.M. Jones" <rjones@redhat.com> writes:

> On Wed, Mar 27, 2013 at 10:12:42AM -0500, Anthony Liguori wrote:
>> "Richard W.M. Jones" <rjones@redhat.com> writes:
>> 
>> > From: "Richard W.M. Jones" <rjones@redhat.com>
>> >
>> >   qemu-system-x86_64 -drive file=ssh://hostname/some/image
>> >
>> > QEMU will ssh into 'hostname' and open '/some/image' which is made
>> > available as a standard block device.
>> >
>> > You can specify a username (ssh://user@host/...) and/or a port number
>> > (ssh://host:port/...).
>> >
>> > Current limitations:
>> >
>> > - Authentication must be done without passwords or passphrases, using
>> >   ssh-agent.  Other authentication methods are not supported. (*)
>> >
>> > - New remote files cannot be created. (*)
>> >
>> > - Uses a single connection, instead of concurrent AIO with multiple
>> >   SSH connections.
>> >
>> > (*) = potentially easy fix
>> >
>> > This is implemented using libssh2 on the client side.  The server just
>> > requires a regular ssh daemon with sftp-server support.  Most ssh
>> > daemons on Unix/Linux systems will work out of the box.
>> >
>> > Thanks: Stefan Hajnoczi, Kevin Wolf.
>> 
>> Curl actually supports sftp already.  In theory, we just need to add:
>> 
>> static BlockDriver bdrv_sftp = {
>>     .format_name     = "sftp",
>>     .protocol_name   = "sftp",
>> 
>>     .instance_size   = sizeof(BDRVCURLState),
>>     .bdrv_file_open  = curl_open,
>>     .bdrv_close      = curl_close,
>>     .bdrv_getlength  = curl_getlength,
>> 
>>     .bdrv_aio_readv  = curl_aio_readv,
>> };
>> 
>> To block/curl.c and it should Just Work.   Have you considered doing
>> this through curl?
>
> Yes, and it doesn't work.  See:
>
> http://www.mail-archive.com/qemu-devel@nongnu.org/msg162605.html
> (curl-based patch:
> http://www.mail-archive.com/qemu-devel@nongnu.org/msg162253.html )

Ah, thanks.

Regards,

Anthony Liguori

>
> Rich.
>
> -- 
> Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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