Backend device not found?

Backend device not found?

[Rob Gardner]

Can somebody help with what must be a really simple problem? I've got a 
stock xen 3.0 installation on a brand new Redhat ES4 installation. I've 
got all the usual stuff installed - brutils, iproute2, hotplug, etc. 
Dom0 boots fine, and xend starts up ok. But when I try to start domU 
using the command:
    xm create -f /etc/xen/xmexample2 vmid=4 
kernel="/boot/vmlinuz-2.6.12-xenU" -c
I get the message:
  Using config file "/etc/xen/xmexample2". 
  Error: Device 0 (vif) could not be connected. Backend device not found.
Appending "nics=0" to the command line makes the problem error go away, 
but of course networking doesn't work.

Two other data points: First, the exact same xen and dom0/domU binaries 
work fine on another installation. Second, I saw this exact problem two 
months ago. So I have to assume it's some kind of configuration error, 
since I don't recall seeing other people reporting this behavior.

Thanks for any suggestions.

Rob

Re: Backend device not found? (Solved)

[Rob Gardner]

I figured out this problem, in case anyone is interested. I had 
installed bridge-utils-1.0.6, which by default installs brctl in 
/usr/local/sbin, which is not in the execution path of xm. Hence, brctl 
was not being found when trying to create a domain. Don't know why xm 
didn't just inherit the value of my PATH variable. Maybe a bug?

Rob


Rob Gardner wrote:

> Can somebody help with what must be a really simple problem? I've got 
> a stock xen 3.0 installation on a brand new Redhat ES4 installation. 
> I've got all the usual stuff installed - brutils, iproute2, hotplug, 
> etc. Dom0 boots fine, and xend starts up ok. But when I try to start 
> domU using the command:
>    xm create -f /etc/xen/xmexample2 vmid=4 
> kernel="/boot/vmlinuz-2.6.12-xenU" -c
> I get the message:
>  Using config file "/etc/xen/xmexample2".  Error: Device 0 (vif) could 
> not be connected. Backend device not found.
> Appending "nics=0" to the command line makes the problem error go 
> away, but of course networking doesn't work.
>
> Two other data points: First, the exact same xen and dom0/domU 
> binaries work fine on another installation. Second, I saw this exact 
> problem two months ago. So I have to assume it's some kind of 
> configuration error, since I don't recall seeing other people 
> reporting this behavior.
>
> Thanks for any suggestions.
>
> Rob
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

Re: Backend device not found? (Solved)

[Ewan Mellor]

On Mon, Jan 23, 2006 at 11:48:24AM -0700, Rob Gardner wrote:

> I figured out this problem, in case anyone is interested. I had 
> installed bridge-utils-1.0.6, which by default installs brctl in 
> /usr/local/sbin, which is not in the execution path of xm. Hence, brctl 
> was not being found when trying to create a domain. Don't know why xm 
> didn't just inherit the value of my PATH variable. Maybe a bug?

xen-hotplug-common.sh is sanitising the PATH.  That seems a sensible thing to
do, but I don't see any problem with adding /usr/local/sbin at the end of
that.

Ewan.