to long interface names

asked 2017-03-30 09:45:15 -0600

minimike gravatar image

updated 2017-03-30 16:35:29 -0600

Hi there

I've got an issue by creating HVM guests. My environment Ubuntu 17.04 with XEN 4.8 (xenproject) nova 7.1.0, libvirtd 2.5.0, openvswitch 2.6.1. So far OpenStack Ocata.. The issue by using linuxbridges with libvirt, libxenlight and nova is that the names of the virtual interfaces are to long. So brctl couldn't work with it. The issue with the to long names is only present by creating HVM guests. At last with PVM guests it works. Anyway is there a way to configure the max lenght of an virtual interface name?

cat /var/log/xen/xen-hotplug.log Error: argument "tap5b6d941e-50-emu" is wrong: "name" too long

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answered 2017-04-02 15:20:21 -0600

tze gravatar image

I use newton release with libvirt xen on openSUSE, and i had the same error. The error comes from interface suffix name that xen use. The problem caused from script /etc/xen/scripts/ as you can see the script try to create an interface with name something like tap320055bf-15-emu (for hvm is tap, for pv is not emulated so not cause error) but xen supports until 16 character devices. So
if you change suffix to be for example -e than -emu the problems solved. So you can change the lines 103 and 111 with changes:

<     dev_=${dev_%-e}
>     dev_=${dev_%-emu}
<         vifname="${vifname}-e"
>         vifname="${vifname}-emu"

You must be careful, if you make any package updates of your xen you must re-apply the patch.

I know this is dirty way but works. I will be very happy if i find another way.

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answered 2017-04-07 08:38:35 -0600

minimike gravatar image

Hey tze

ymmd! :D thank you so much for sharing your workaround. My Windows and FreeBSD instances are running well now

warm regards Darko

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Asked: 2017-03-30 09:45:15 -0600

Seen: 171 times

Last updated: Apr 07 '17