[et-mgmt-tools] [PATCH] waiting VNC port number

[Daniel P. Berrange]

On Wed, Feb 21, 2007 at 12:07:42PM +0900, Saori Fukuta wrote:
> Hi,
> 
> I try to install with virt-install and sometimes vncviewer get an error 
> message that says "unable to connect to host:Connection refused(111)".
> So, I cannot continue installation.
> 
> The attached patch to resolve this issues in the following way:
> 
>   1) Check whether the domain has VNCport number.
>   2) If the number is exist, use the VNCport number.
>   3) If not, check again every 0.25 second up to 40 seconds.

This is no good because it is Xen specific - the code breaks when used
with the QEMU / KVM backend to libvirt. I think this is actually a
combination of two bugs:

 - libvirt looks in xenstore to find the port number, but if it is
   missing hardcodes 5900 + domid. So there is a race condition where
   if virt-install asks for the XML dump, before the framebuffer daemon
    has started up, it will get the wrong port number. 

   This is a hardcoded fallback port number is a hangover from old Xen 
   3.0.2  where the port number was fixed & not kept in xenstore at all. 
   We need to fix libvirt to only use this code on Xen <= 3.0.3

 - Once the above fix in libvirt is done, we can make virt-install do
   a loop like the one you have below, but instead of looking in xenstore
   it will look at the port in the XML - waiting for it to change from '-1'
   to an actual port number

Regards
Dan.
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