[ovs-discuss] a question regarding to tap internal interface

Ben Pfaff blp at ovn.org
Sat Mar 16 17:44:53 UTC 2019

On Sat, Mar 16, 2019 at 11:24:34AM +0000, pei Jikui wrote:
> hi,
> 1) From the openstack documents, we know that for the tenant's dhcp functionality, the usage is to connect a dhcp netns to the ovs using a tap interface.
> At the same time, the ovs-vsctl show that the tap interface is a type of internal interface for OVS.

This is wrong.  Tap and internal are different kinds of interfaces.
What does ovs-vsctl show that makes you confuse the two?

> While I could not add a tap type interface to ovs as an internal type of interface for OVS.
> The commands I used,
> a) ip tuntap add dev tap0 mode tap.
> b) ovs-vsctl add-port ovs0 tap0 -- set inteface tap0 type=internal

These commands are wrong.  If you create a tap interface, you must not
tell ovs-vsctl that it is an internal interface.

What led you to believe that these commands were correct?

> error: "could not add network device tap12 to ofproto (No such device)"
> 2) My questions are ,
>    a) how to add a tap interface to OVS and set it as internal type of interface of OVS?

You cannot.  That is not possible.

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