[ovs-discuss] Two GRE tunnels with same src/dst

Jesse Gross jesse at nicira.com
Tue Jan 4 22:34:42 UTC 2011

On Thu, Dec 30, 2010 at 6:00 PM, Frank <frank at cloud.com> wrote:
> Hi guys:
>    I just try to create two GRE tunnels between two hosts, the result is I
> can't do this.
>    vswitch complains "could not create iface test: File exists" when
> creating second tunnel.
>    I did set different GRE keys for tunnels.
>    I google and get some articles said it's possible to create multiple GRE
> tunnels with same src/dst.
>    I am curious what technical barrier prevents our doing since GRE key is
> an natural tag to distinguish different tunnels.

You can have multiple tunnels between the same endpoints if they are
distinguished by key.  Please post your interface config.

>    BTW: when the interface created failed, ovs-vsctl also returns a uuid as
> if it succeeds. This is very puzzle, the real result in log is:
> "
> Dec 30 14:40:06|04201|bridge|INFO|created port test on bridge test
> Dec 30 14:40:06|04202|bridge|WARN|could not create iface test: File exists
> Dec 30 14:40:06|04203|bridge|WARN|bridge test: port test has no interfaces,
> dropping
> "
>    cloud we have more graceful way to report such failure?

It's not as straightforward as it might seem while maintaining good
abstraction.  ovs-vsctl writes into the database, which only enforces
some basic constraints.  ovs-vswitchd then picks up the config, does
the actual port creation, and generates those log messages.

Patches are, of course, welcome.

More information about the discuss mailing list