From 539d1898ebbf429f222fade0e5a6c36e32a30c1b Mon Sep 17 00:00:00 2001 From: Ihar Hrachyshka Date: Mon, 11 Jan 2016 17:09:24 +0100 Subject: [PATCH] neutron: enable MTU advertisement This is needed if you want to run devstack using tunnelling for tenant networks as well as multiple nodes. In this case, packets get additional encapsulation header, and if packets are of physical device mtu size, tunnelled data can be dropped, especially when "Dont Fragment" (DF) flag is set. MTU is currently advertised using DHCP option only. It works as long as guests know how to handle it. (Cirros honors the option as of 0.3.4). Note this patch is Liberty only. For Mitaka, we plan to change the default value for the option to True (see the dependency). We won't be able to backport the neutron patch to stable release since it violates stable maintenance rules. Change-Id: I53c0a29438d0d6433efd4b379bc0391a69d26589 Depends-On: I5cbbc4660f8c4e15e59f8f5ce0419501bdd27348 Related-Bug: #1527675 --- lib/neutron-legacy | 3 +++ 1 file changed, 3 insertions(+) diff --git a/lib/neutron-legacy b/lib/neutron-legacy index 2a0b3936e6..df33050e25 100755 --- a/lib/neutron-legacy +++ b/lib/neutron-legacy @@ -957,6 +957,9 @@ function _configure_neutron_common { fi _neutron_setup_rootwrap + + # push mtu into instances to avoid packet drops when tunnelling is used + iniset $NEUTRON_CONF DEFAULT advertise_mtu "True" } function _configure_neutron_debug_command {