GRE segmentation issue drops packets over 1438 bytes long

[Tom Christensen]

OpenStack Icehouse release running on ubuntu 14.04 using GRE tunnels, packets over 1438 bytes long are dropped and not segmented. This causes many issues, not least of which is you cannot inject an ssh key into an ubuntu 14.04 guest using the metadata service.

I have attached tcpdump to the tap interface, the br-int bridge, the br-tun bridge, and I can see a small packet traverse the path all the way to the physical interface leaving the compute node. When I attempt to send a packet of 1439 bytes, it enters the br-int bridge, but never leaves.

[Tom Christensen (pavera)]

I should add I have attempted all of the workarounds I've found online for mtu issues, including setting the mtu inside the VM to 1400, 1300, and even 500. I've also attempted disabling all offloading (gro, gso, etc).

[Jack McCann (jack-mccann)]

I think you want https://review.openstack.org/#/c/75281

[Eugene Nikanorov (enikanorov)]

What configuration revealed that issue? Release name, core plugin configuration? Anything specific?

[Armando Migliaccio (armando-migliaccio)]

This bug is > 172 days without activity. We are unsetting assignee and milestone and setting status to Incomplete in order to allow its expiry in 60 days.

If the bug is still valid, then update the bug status.

[Armando Migliaccio (armando-migliaccio)]

This bug is > 180 days without activity. We are unsetting assignee and milestone and setting status to Incomplete in order to allow its expiry in 60 days.

If the bug is still valid, then update the bug status.

[Launchpad Janitor (janitor)]

[Expired for neutron because there has been no activity for 60 days.]

[Launchpad Janitor (janitor)]

[Expired for Ubuntu because there has been no activity for 60 days.]