[Sheepdog] Sheep, with no local storage?

[Floris Bos]

Hi,

On Sunday, October 03, 2010 10:14:29 pm Robert Terhaar wrote:
> I emailed with Kazutaka off-list about this- duplicating here.
> 
> 
> Is it required to run a local sheep storage in order to use the sheepdog
> qemu block driver? It seems that 'localhost:7000' is hard-coded into the
> top of sheepdog.c in the qemu source.

It seems hostname/port is extracted in parse_vdiname() and put in "s->addr" 
and "s->port":

http://git.savannah.gnu.org/cgit/qemu.git/tree/block/sheepdog.c#n937

Most functions use that when connecting, like this:

==
fd = connect_to_sdog(s->addr, s->port);
==

So opening an EXISTING VDI located on an external sheepdog server should work, 
by specifying the [hostname]:[port] in the VDI name, like Kazutaka said.



However I think that CREATING new VDIs on an external sheepdog server is not 
implemented/broken.

do_sd_create() does not use s->addr, but a function parameter.

http://git.savannah.gnu.org/cgit/qemu.git/tree/block/sheepdog.c#n1244

==
static int do_sd_create(char *filename, int64_t vdi_size,
                        uint32_t base_vid, uint32_t *vdi_id, int snapshot,
                        const char *addr, const char *port)
{
    SheepdogVdiReq hdr;
    SheepdogVdiRsp *rsp = (SheepdogVdiRsp *)&hdr;
    int fd, ret;
    unsigned int wlen, rlen = 0;
    char buf[SD_MAX_VDI_LEN];

    fd = connect_to_sdog(addr, port);
==

And do_sd_create() is called with the "addr" parameter hardcoded to null in 
sd_create(), making it always use the default of localhost:7000 when creating 
new VDIs:

http://git.savannah.gnu.org/cgit/qemu.git/tree/block/sheepdog.c#n937

==
return do_sd_create((char *)filename, vdi_size, vid, NULL, 0, NULL, NULL);
==


Yours sincerely,

Floris Bos