Raghu Nallamothu
2013-May-25 04:11 UTC
Attaching pre created tap interfaces to a VM in Xen for Routed Networking
Hi All.,
I am not sure if this is possible in xen via Libvirt, but what I
am trying to do is, I want libvirt to launch a VM and attach a pre-created
tap interface to that VM ( I do not want XEN to create one, as I am running
a lot of custom scripts on my tap interface). I also dont want xen to
attach this tap interface to a bridge.
For example, lets say I have created a tap interface with name
"tap123456"
when libvirt launches my VM in xen, I want the VM to read its networking
info from this tap interface.
But I wasn''t so successful in doing this when ever I am trying to do
this,
I am seeing the following error message "VmError: Device 0 (vif) could not
be connected. Hotplug scripts not working." and "error: POST operation
failed: xend_post: error from xen daemon: (xend.err ''Device 0 (vif)
could
not be connected. Cannot rename interface vif4.0. An interface with name
tap12345 already exists.'')". But I dont want xen to create
another
interface and rename it, rather want xen to use the existing one
=== output of lsmod ==
bash-4.1# lsmod | grep xen
xen_acpi_processor 4465 0
xen_netback 25455 0 [permanent]
xen_gntdev 9504 2
xen_evtchn 4899 3
xenfs 2943 1
xen_privcmd 4972 19 xenfs
==== end of output ===
My Configuration : Centos 6.2 with Xen 4.2.5 along with Libvirt
Libvirt Configuration file,
<domain type=''xen''>
<name>raghu_12345</name>
<uuid>12113325-d948-4a1b-b673-888a16b90726</uuid>
<memory>1048576</memory>
<vcpu>1</vcpu>
<os>
<type>hvm</type>
<loader>/usr/lib/xen/boot/hvmloader</loader>
<boot dev=''hd''/>
</os>
<on_poweroff>destroy</on_poweroff>
<on_reboot>restart</on_reboot>
<on_crash>restart</on_crash>
<features>
<pae/>
<acpi/>
<apic/>
</features>
<devices>
<emulator>/usr/lib/xen/bin/qemu-dm</emulator>
<interface type="ethernet">
<mac address=''00:25:90:3f:25:91''/> <!-- I want this
mac to be mac address
of a vm -->
<target dev=''tap123456''/>
</interface>
<disk type=''file'' device=''disk''>
<source file=''~/tmp/lucid.img''/>
<target dev=''hda''/>
</disk>
<console type=''pty''>
<target port=''0''/>
</console>
<graphics port=''-1'' type=''vnc''
autoport=''yes'' listen=''0.0.0.0''/>
</devices>
</domain>
I have a pre-created tap interface with name ''tap123456''
with all the
networking setup with dhcp and dns running.
Thanks for your time and help.
Regards
Raghu
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Wei Liu
2013-May-25 13:45 UTC
Re: Attaching pre created tap interfaces to a VM in Xen for Routed Networking
Hi This list is mainly about Xen development. You might have better luck asking this kind of questions on xen-users@lists.xen.org Wei. On Fri, May 24, 2013 at 09:11:04PM -0700, Raghu Nallamothu wrote:> Hi All., > I am not sure if this is possible in xen via Libvirt, but what I > am trying to do is, I want libvirt to launch a VM and attach a pre-created > tap interface to that VM ( I do not want XEN to create one, as I am running > a lot of custom scripts on my tap interface). I also dont want xen to > attach this tap interface to a bridge. > > For example, lets say I have created a tap interface with name "tap123456" > when libvirt launches my VM in xen, I want the VM to read its networking > info from this tap interface. > > But I wasn''t so successful in doing this when ever I am trying to do this, > I am seeing the following error message "VmError: Device 0 (vif) could not > be connected. Hotplug scripts not working." and "error: POST operation > failed: xend_post: error from xen daemon: (xend.err ''Device 0 (vif) could > not be connected. Cannot rename interface vif4.0. An interface with name > tap12345 already exists.'')". But I dont want xen to create another > interface and rename it, rather want xen to use the existing one > > === output of lsmod ==> > bash-4.1# lsmod | grep xen > xen_acpi_processor 4465 0 > xen_netback 25455 0 [permanent] > xen_gntdev 9504 2 > xen_evtchn 4899 3 > xenfs 2943 1 > xen_privcmd 4972 19 xenfs > > ==== end of output ===> > My Configuration : Centos 6.2 with Xen 4.2.5 along with Libvirt > > > Libvirt Configuration file, > > <domain type=''xen''> > > <name>raghu_12345</name> > <uuid>12113325-d948-4a1b-b673-888a16b90726</uuid> > <memory>1048576</memory> > <vcpu>1</vcpu> > > > <os> > <type>hvm</type> > <loader>/usr/lib/xen/boot/hvmloader</loader> > <boot dev=''hd''/> > </os> > > <on_poweroff>destroy</on_poweroff> > <on_reboot>restart</on_reboot> > <on_crash>restart</on_crash> > > <features> > <pae/> > <acpi/> > <apic/> > </features> > > > <devices> > <emulator>/usr/lib/xen/bin/qemu-dm</emulator> > <interface type="ethernet"> > <mac address=''00:25:90:3f:25:91''/> <!-- I want this mac to be mac address > of a vm --> > <target dev=''tap123456''/> > </interface> > <disk type=''file'' device=''disk''> > <source file=''~/tmp/lucid.img''/> > <target dev=''hda''/> > </disk> > <console type=''pty''> > <target port=''0''/> > </console> > <graphics port=''-1'' type=''vnc'' autoport=''yes'' listen=''0.0.0.0''/> > </devices> > > </domain> > > > I have a pre-created tap interface with name ''tap123456'' with all the > networking setup with dhcp and dns running. > > Thanks for your time and help. > > Regards > Raghu> _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel