From 4a79c2a6a1baec572dca57573655b2161b2ff6eb Mon Sep 17 00:00:00 2001
From: Roger Luethi <rl@patchworkscience.org>
Date: Sun, 21 Sep 2014 19:46:25 +0200
Subject: [PATCH] labs: set lower MTU for bridge to instance VM

The MTU on the bridge to the instance VMs needs to be lower than 1500 to
compensate for the GRE overhead. With an MTU of 1500, one thing that
fails is ssh authentication (into the instance VM).

This patch does not help for the CirrOS 0.3.2 image which we currently
use, because it is not able to pick up MTU values via DHCP.

Change-Id: I2a04b62beef6120e811f00472aa7395ab3d683dc
Co-Authored-By: Pranav Salunke <dguitarbite@gmail.com>
---
 labs/scripts/setup_neutron_network.sh | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/labs/scripts/setup_neutron_network.sh b/labs/scripts/setup_neutron_network.sh
index 9fa81dcc..5b59dc28 100755
--- a/labs/scripts/setup_neutron_network.sh
+++ b/labs/scripts/setup_neutron_network.sh
@@ -131,6 +131,14 @@ iniset_sudo $conf DEFAULT interface_driver neutron.agent.linux.interface.OVSInte
 iniset_sudo $conf DEFAULT dhcp_driver neutron.agent.linux.dhcp.Dnsmasq
 iniset_sudo $conf DEFAULT use_namespaces True
 iniset_sudo $conf DEFAULT verbose True
+iniset_sudo $conf DEFAULT dnsmasq_config_file /etc/neutron/dnsmasq-neutron.conf
+
+cat << DNSMASQ | sudo tee /etc/neutron/dnsmasq-neutron.conf
+# Set interface MTU to 1454 (for instance, ssh authentication may fail
+# otherwise due to GRE overhead)
+dhcp-option-force=26,1454
+DNSMASQ
+killall dnsmasq
 
 echo "Restarting the network service."
 sudo service neutron-plugin-openvswitch-agent restart