Xen users - Feb 2008 - xen-3.0.4 networking problem after migration

Hello,

I am facing an networking problem for xen migration. I used to have it 
working fine. But as I worked with several trees, I lost track on the 
correct configuration I should have.

The problem is as this, with xen-3.0.4 on CentOS-4.4. I can install xen, 
start xend, and create domU, all fine.
# xend start (on both nodes)
# ssh node02 xend start

Then create a domU on node01
# xm create -c cvm.01

At this point, I can ping this domU from many different nodes in the 
subnet. Then, I migrate it to node02
# xm migrate cvm.01 -l node02

Right after the migration, I can no long ping the domU. This domU now 
can only be ping''ed from the new host, node02. Interestingly, if I 
migrate the same domU back to node01. Pinging works fine again from many 
different nodes.

Anybody has seen this before? I know xen-3.0.4 is old by now. But want 
to avoid a new installation if possible.

Can somebody offer a hint? Any help is appreciated.

-- Weikuan

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I reply to my post earlier. It was a problem on the configuration file. 
It appears that, when not using dhcp, live migration with static mac 
address would cause a problem to IP in migrated domU.

--Weikuan

Weikuan Yu wrote:
> Hello,
> 
> I am facing an networking problem for xen migration. I used to have it 
> working fine. But as I worked with several trees, I lost track on the 
> correct configuration I should have.
> 
> The problem is as this, with xen-3.0.4 on CentOS-4.4. I can install xen, 
> start xend, and create domU, all fine.
> # xend start (on both nodes)
> # ssh node02 xend start
> 
> Then create a domU on node01
> # xm create -c cvm.01
> 
> At this point, I can ping this domU from many different nodes in the 
> subnet. Then, I migrate it to node02
> # xm migrate cvm.01 -l node02
> 
> Right after the migration, I can no long ping the domU. This domU now 
> can only be ping''ed from the new host, node02. Interestingly, if I
> migrate the same domU back to node01. Pinging works fine again from many 
> different nodes.
> 
> Anybody has seen this before? I know xen-3.0.4 is old by now. But want 
> to avoid a new installation if possible.
> 
> Can somebody offer a hint? Any help is appreciated.
> 
> -- Weikuan
> 

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Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

xen-users-bounces@lists.xensource.com a écrit sur 19/02/2008 06:30:54 :
> I reply to my post earlier. It was a problem on the configuration file. 
> It appears that, when not using dhcp, live migration with static mac 
> address would cause a problem to IP in migrated domU.
We are also using xen 3.0.x, we are not using DHCP, we have static MAC 
address in our domU, and we never encountered such a problem in live 
migrations.

Maybe another explanation ?
> 
> --Weikuan
> 
> Weikuan Yu wrote:
> > Hello,
> > 
> > I am facing an networking problem for xen migration. I used to have it
> > working fine. But as I worked with several trees, I lost track on the 
> > correct configuration I should have.
> > 
> > The problem is as this, with xen-3.0.4 on CentOS-4.4. I can install 
xen, 
> > start xend, and create domU, all fine.
> > # xend start (on both nodes)
> > # ssh node02 xend start
> > 
> > Then create a domU on node01
> > # xm create -c cvm.01
> > 
> > At this point, I can ping this domU from many different nodes in the 
> > subnet. Then, I migrate it to node02
> > # xm migrate cvm.01 -l node02
> > 
> > Right after the migration, I can no long ping the domU. This domU now 
> > can only be ping''ed from the new host, node02. Interestingly,
if I
> > migrate the same domU back to node01. Pinging works fine again from 
many 
> > different nodes.
> > 
> > Anybody has seen this before? I know xen-3.0.4 is old by now. But want
> > to avoid a new installation if possible.
> > 
> > Can somebody offer a hint? Any help is appreciated.
> > 
> > -- Weikuan
> > 
> 
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users

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Alain BARTHE wrote:
> 
> xen-users-bounces@lists.xensource.com a écrit sur 19/02/2008 06:30:54 :
> 
>  > I reply to my post earlier. It was a problem on the configuration
file.
>  > It appears that, when not using dhcp, live migration with static mac
>  > address would cause a problem to IP in migrated domU.
> 
> We are also using xen 3.0.x, we are not using DHCP, we have static MAC 
> address in our domU, and we never encountered such a problem in live 
> migrations.
> 
> Maybe another explanation ?
Here is the line that caused trouble to domU.
# vif = [ ''mac=aa:00:00:00:b3:01, bridge=xenbr0'' ]
compared to the following that works.
# vif = ['''']

It could be due to ''bridge=xenbr0'' then.

--Weikuan
> 
>  >
>  > --Weikuan
>  >
>  > Weikuan Yu wrote:
>  > > Hello,
>  > >
>  > > I am facing an networking problem for xen migration. I used to
have it
>  > > working fine. But as I worked with several trees, I lost track
on the
>  > > correct configuration I should have.
>  > >
>  > > The problem is as this, with xen-3.0.4 on CentOS-4.4. I can
install
> xen,
>  > > start xend, and create domU, all fine.
>  > > # xend start (on both nodes)
>  > > # ssh node02 xend start
>  > >
>  > > Then create a domU on node01
>  > > # xm create -c cvm.01
>  > >
>  > > At this point, I can ping this domU from many different nodes in
the
>  > > subnet. Then, I migrate it to node02
>  > > # xm migrate cvm.01 -l node02
>  > >
>  > > Right after the migration, I can no long ping the domU. This
domU now
>  > > can only be ping''ed from the new host, node02.
Interestingly, if I
>  > > migrate the same domU back to node01. Pinging works fine again
from
> many
>  > > different nodes.
>  > >
>  > > Anybody has seen this before? I know xen-3.0.4 is old by now.
But want
>  > > to avoid a new installation if possible.
>  > >
>  > > Can somebody offer a hint? Any help is appreciated.
>  > >
>  > > -- Weikuan
>  > >
>  >
>  >
>  > _______________________________________________
>  > Xen-users mailing list
>  > Xen-users@lists.xensource.com
>  > http://lists.xensource.com/xen-users
-- 
Weikuan Yu <+> 1-865-574-7990
http://ft.ornl.gov/~wyu/

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

xen-users-bounces@lists.xensource.com a écrit sur 19/02/2008 14:18:06
:
> Alain BARTHE wrote:
> > 
> > xen-users-bounces@lists.xensource.com a écrit sur 19/02/2008 06:30:54 
:
> > 
> >  > I reply to my post earlier. It was a problem on the
configuration
file.
> >  > It appears that, when not using dhcp, live migration with static
mac
> >  > address would cause a problem to IP in migrated domU.
> > 
> > We are also using xen 3.0.x, we are not using DHCP, we have static MAC
> > address in our domU, and we never encountered such a problem in live 
> > migrations.
> > 
> > Maybe another explanation ?
> 
> Here is the line that caused trouble to domU.
> # vif = [ ''mac=aa:00:00:00:b3:01, bridge=xenbr0'' ]
> compared to the following that works.
> # vif = ['''']
> 
> It could be due to ''bridge=xenbr0'' then.
When a domU is migrated, I think that the configuration file is not used 
at all: the domU is migrated as is, the config file is used only at the 
domU creation time.
Normally, if you create a domU from a config file that has an empty
"vif"
parameter, you should not have any network at all in your domU.
> 
> --Weikuan
> 
> > 
> >  >
> >  > --Weikuan
> >  >
> >  > Weikuan Yu wrote:
> >  > > Hello,
> >  > >
> >  > > I am facing an networking problem for xen migration. I used
to
have it
> >  > > working fine. But as I worked with several trees, I lost
track on
the
> >  > > correct configuration I should have.
> >  > >
> >  > > The problem is as this, with xen-3.0.4 on CentOS-4.4. I can
install 
> > xen,
> >  > > start xend, and create domU, all fine.
> >  > > # xend start (on both nodes)
> >  > > # ssh node02 xend start
> >  > >
> >  > > Then create a domU on node01
> >  > > # xm create -c cvm.01
> >  > >
> >  > > At this point, I can ping this domU from many different
nodes in
the
> >  > > subnet. Then, I migrate it to node02
> >  > > # xm migrate cvm.01 -l node02
> >  > >
> >  > > Right after the migration, I can no long ping the domU.
This domU
now
> >  > > can only be ping''ed from the new host, node02.
Interestingly, if
I
> >  > > migrate the same domU back to node01. Pinging works fine
again
from 
> > many
> >  > > different nodes.
> >  > >
> >  > > Anybody has seen this before? I know xen-3.0.4 is old by
now. But
want
> >  > > to avoid a new installation if possible.
> >  > >
> >  > > Can somebody offer a hint? Any help is appreciated.
> >  > >
> >  > > -- Weikuan
> >  > >
> >  >
> >  >
> >  > _______________________________________________
> >  > Xen-users mailing list
> >  > Xen-users@lists.xensource.com
> >  > http://lists.xensource.com/xen-users
> 
> -- 
> Weikuan Yu <+> 1-865-574-7990
> http://ft.ornl.gov/~wyu/
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

> 
> When a domU is migrated, I think that the configuration file is not used 
> at all: the domU is migrated as is, the config file is used only at the 
> domU creation time.
What you mentioned could be true. But the problem I had was due to the 
vif line mentioned.
> Normally, if you create a domU from a config file that has an empty 
> "vif" parameter, you should not have any network at all in your
domU.
What you said is true when there is no vif line. Anyway, there seems to 
be some differences in our experience. It works fine for me though. 
Thanks for your attention.

--Weikuan


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