Re: [Qemu-devel] [PATCH for-4.0 00/14] nbd: add qemu-nbd --list

[Richard W.M. Jones]

On Sat, Dec 01, 2018 at 07:57:51AM -0600, Eric Blake wrote:
> On 12/1/18 1:42 AM, Richard W.M. Jones wrote:
> >On Fri, Nov 30, 2018 at 04:03:29PM -0600, Eric Blake wrote:
> >>I note that upstream NBD has 'nbd-client -l $host' for querying
> >>just export names (with no quoting, so you have to know that
> >>a blank line means the default export), but it wasn't powerful
> >>enough, so I implemented 'qemu-nbd -L' to document everything.
> >>Upstream NBD has separate 'nbd-client' and 'nbd-server' binaries,
> >>while we only have 'qemu-nbd' (which is normally just a server,
> >>but 'qemu-nbd -c' also operates a second thread as a client).
> >>Our other uses of qemu as NBD client are for consuming a block
> >>device (as in qemu-io, qemu-img, or a drive to qemu) - but those
> >>binaries are less suited to something so specific to the NBD
> >>protocol.
> >
> >I tried it against nbdkit and it works (obviously):
> >
> >$ ./qemu-nbd -L
> >exports available: 1
> >  export: ''
> >   size:  67108864
> >   flags: 0x61 ( trim zeroes )
> >
> >What I couldn't work out is how to connect to other hosts.  It's
> >possible to add -p or -k to change the localhost port number or to use
> >a Unix domain socket (and I checked both work).  However can we
> >connect to remote hosts?
> 
> Should work by adding '-b host' (if -b is omitted, it defaults to
> 0.0.0.0).  However, I admit that so far I have only tested '-b
> localhost' or '-b 127.0.0.1' (per the iotest additions at the end of
> the series), so it could well be something that I missed in setting
> up the client socket in nbd_build_socket_address().

Must have missed that option.  It does work, thanks.

Rich.

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