xenapi: glance download can hang if interupted

[John Garbutt]

We have seen cases where a server has got stuck building during the glance download.

Looks like the download process just hangs.

[John Garbutt (johngarbutt)]

Most likely cause seems to be loosing the connection to glance, then the script locks up.

It sounds a lot like what is described here:
http://docs.python.org/3.1/howto/urllib2.html#sockets-and-layers

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/56622

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/56622
Committed: http://github.com/openstack/nova/commit/89b0d540d5f98945600139bd2a05656b68fac81a
Submitter: Jenkins
Branch: master

commit 89b0d540d5f98945600139bd2a05656b68fac81a
Author: John Garbutt <email address hidden>
Date: Fri Nov 15 14:46:38 2013 +0000

    xenapi: stop hang during glance download

    It seems there are cases when the server gets stuck in a building state
    because the download from glance fails, but the nova-compute doesn't
    find out.

    After some code inspect, a likely cause seems to related to having no
    socket timeout inside urllib2 when we download the image from glance. A
    workaround for this issue is to configure the default socket timeout as
    described here:
    http://docs.python.org/3.1/howto/urllib2.html#sockets-and-layers

    Fixes bug 1251650
    Change-Id: I8b34d95d3524f3825b28e61cbbb59290653d3711