Re: [Xen-devel] Race with hotplug vif scripts - Jacob Gorm Hansen - com.xensource.lists.xen-devel

4 messages in com.xensource.lists.xen-develRe: [Xen-devel] Race with hotplug vif...

From	Sent On	Attachments
Jacob Gorm Hansen	30 Dec 2006 10:52
Keir Fraser	30 Dec 2006 11:02
Jacob Gorm Hansen	30 Dec 2006 11:18
Ewan Mellor	02 Jan 2007 06:51

Subject:	Re: [Xen-devel] Race with hotplug vif scripts
From:	Jacob Gorm Hansen (jac...@diku.dk)
Date:	12/30/2006 11:18:00 AM
List:	com.xensource.lists.xen-devel

On Sat, 2006-12-30 at 19:52 +0100, Jacob Gorm Hansen wrote:

hi,

I have a domU running a custom HTTP client. As soon as the domain is booted and the VIF running it wants to initiate a connection. However, I seem to be having a race where the domU starts using the VIF before it is completely functional, probably because the hotplug script has not completed.

Currently I just set the frontend to '4', and just wait for the backend state to also become '4' (connected), but this does not work in all cases. How can I synchronize with the hotplug script, and what is the correct sequence of XenBus states?

Ahh never mind, the issue seems to be with TCP connection setup, the server gets confused due to the shortlived domain reusing the same source port number over and over. A little randomness fixes the problem.

Jacob