Re: [Xen-devel] [patch] xen udev rule interfering with openvpn

[Teck Choon Giam <giamteckchoon@xxxxxxxxx>]

On Wed, May 23, 2012 at 5:37 PM, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
> On Wed, 2012-05-23 at 03:22 +0100, Teck Choon Giam wrote:
>
>> >
>> > I think the reason this effects xm and not xl is that libxl uses
>> > script=none to disable qemu-ifup while xend does not and instead ends up
>> > using qemu-ifup which does some fiddling with the device too, including
>> > bringing it up.
>>
>> Ok, so default for xend is using script=qemu-ifup if script is not
>> set?  Am I right about this?
>
> Yes.

Thanks for clarifying.

>
>> > The proper fix is probably to change xend, I'm a bit wary of this,
>> > especially for a 4.1 backport, but the following looks right and works
>> > for me. It's a bit more complex since in libxl we seem to only do this
>> > for Linux (i.e. not NetBSD) and I guess we should do the same in xend
>> > too.
>>
>> Err... if we are going to change default behaviour will we be
>> affecting those users who is upgrading from xen-4.1 to xen-4.2?
>
> This was already a deliberate change made in xl, it does not effect the
> guest config, only the mechanisms by which that configuration is
> achieved. I think extending this to xend in order not to break xend in
> 4.2 is worthwhile.

Noted.

>
> I don't think we should be backporting any of this to 4.1 though.

You mean your tap to -emu patch series including the latest fix patch
you posted shouldn't be backporting to 4.1?  If this is so, I am fine
since there isn't much difference for me as personally I kept few
custom patches in own xen packages.  Of course whatever get into
upstream is better though :p

>
>> If your fix patch is going into xen-unstable for sure, I will re-run
>> my tests by then.  I hope it doesn't affect current domUs
>> configuration (I mean we shouldn't need to change domU configuration)
>> especially when users prefer to use xm then xl in xen-4.2.
>
> There should be no guest config change necessary.

Noted.

>
> Ian.

Thanks for taking time to provide fix and responses.

Kindest regards,
Giam Teck Choon



>
>>
>> Thanks.
>>
>> Kindest regards,
>> Giam Teck Choon
>>
>>
>> >
>> > Ian
>> >
>> > # HG changeset patch
>> > # User Ian Campbell <ian.campbell@xxxxxxxxxx>
>> > # Date 1337692747 -3600
>> > # Node ID 426bbf58cea4559464b6e5d3ff0f65324a5f5926
>> > # Parent  72ca5bc4eb6b91fa8dff51d439bd05f5586179df
>> > xend: do not run a hotplug script from qemu on Linux
>> >
>> > The current vif-hotplug-common.sh for renaming the tap device is failing
>> > because it is racing with this script and therefore the device is 
>> > unexpectedly
>> > up when we come to rename it.
>> >
>> > Fix this in the same way as libxl does, by disabling the script (only on
>> > Linux).
>> >
>> > Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
>> >
>> > diff -r 72ca5bc4eb6b -r 426bbf58cea4 tools/python/xen/xend/image.py
>> > --- a/tools/python/xen/xend/image.py    Tue May 22 11:29:50 2012 +0100
>> > +++ b/tools/python/xen/xend/image.py    Tue May 22 14:19:07 2012 +0100
>> > @@ -919,8 +919,13 @@ class HVMImageHandler(ImageHandler):
>> >                        (nics, mac, model))
>> >             vifname = "vif%d.%d-emu" % (self.vm.getDomid(), nics-1)
>> >             ret.append("-net")
>> > -            ret.append("tap,vlan=%d,ifname=%s,bridge=%s" %
>> > -                       (nics, vifname, bridge))
>> > +            if osdep.tapif_script is not None:
>> > +                script=",script=%s,downscript=%s" % \
>> > +                        (osdep.tapif_script, osdep.tapif_script)
>> > +            else:
>> > +                script=""
>> > +            ret.append("tap,vlan=%d,ifname=%s,bridge=%s%s" %
>> > +                       (nics, vifname, bridge, script))
>> >
>> >         if nics == 0:
>> >             ret.append("-net")
>> > diff -r 72ca5bc4eb6b -r 426bbf58cea4 tools/python/xen/xend/osdep.py
>> > --- a/tools/python/xen/xend/osdep.py    Tue May 22 11:29:50 2012 +0100
>> > +++ b/tools/python/xen/xend/osdep.py    Tue May 22 14:19:07 2012 +0100
>> > @@ -30,6 +30,10 @@ _vif_script = {
>> >     "SunOS": "vif-vnic"
>> >  }
>> >
>> > +_tapif_script = {
>> > +    "Linux": "no",
>> > +}
>> > +
>> >  PROC_XEN_BALLOON = '/proc/xen/balloon'
>> >  SYSFS_XEN_MEMORY = '/sys/devices/system/xen_memory/xen_memory0'
>> >
>> > @@ -257,6 +261,7 @@ def _get(var, default=None):
>> >
>> >  xend_autorestart = _get(_xend_autorestart)
>> >  vif_script = _get(_vif_script, "vif-bridge")
>> > +tapif_script = _get(_tapif_script)
>> >  lookup_balloon_stat = _get(_balloon_stat, _linux_balloon_stat)
>> >  get_cpuinfo = _get(_get_cpuinfo, _linux_get_cpuinfo)
>> >  prefork = _get(_get_prefork, _default_prefork)
>> >
>> >
>
>

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