Xen VM won't come up: could not find bridge device xenbr0 (configured to use routed)

Question

I am using xen 4.4.1 on an Ubuntu 14.04 server, my DomU is running Ubuntu 14.04 Server as well. I've run this DomU in bridge-mode previously no problems. However I want to switch to a routed setup.

I changed the DomU config vif to:

vif=['10.0.1.2,script=vif-route']

and in /etc/xen/xend-config.sxp:

#(vif-script vif-bridge)
#(network-script network-bridge
(network-script network-route)
(vif-script vif-route)

However when I try to bring up the VM it will throw this error:

libxl: error: libxl_exec.c:118:libxl_report_child_exitstatus: /etc/xen/scripts/vif-bridge online [-1] exited with error status 1
libxl: error: libxl_device.c:1085:device_hotplug_child_death_cb: script: Could not find bridge device xenbr0
libxl: error: libxl_create.c:1226:domcreate_attach_vtpms: unable to add nic devices
libxl: error: libxl_exec.c:118:libxl_report_child_exitstatus: /etc/xen/scripts/vif-bridge offline [-1] exited with error status 1
libxl: error: libxl_device.c:1085:device_hotplug_child_death_cb: script: Could not find bridge device xenbr0
libxl: error: libxl_exec.c:118:libxl_report_child_exitstatus: /etc/xen/scripts/vif-bridge remove [-1] exited with error status 1
libxl: error: libxl_device.c:1085:device_hotplug_child_death_cb: script: Could not find bridge device xenbr0

Why would it still try to run the vif-bridge script even tho I commented it out in xend-config.sxp?

Solution

We had the exact same problem here after updating from xen 4.1 to 4.4 on a debian dom0 (wheezy->jessie).

Solution was to change the xl.conf:

# default vif script to use if none is specified in the guest config
vif.default.script="vif-route"

Comments

[0x0]

What toolstack are you using? From xen 4.4 onwards "xend/xm" is deprecated. xl is the default toolstack. Your errors indicate you are using "xl" but looks like you are changing "xend" config files. Can you elaborate?

[kasperd]

You should explain in detail what those commands would do.