neutron: enable ml2 mtu calculation mechanism
Setting path_mtu to reflect mtu for physical devices that handle traffic
issued from br-tun makes ml2 plugin to calculate mtu for tenant networks
properly, considering encapsulation headers. After that, calculated mtu
values can be propagated into instances (currently, only DHCP approach
is implemented; RA support for IPv6 subnets is under review).
This change allows to run tunnelled tenant networks in multinode when
underlying physical devices don't support jumbo frames.
Note: changing the default value in neutron would not be backwards
compatible, since it could slow down east-west tunnelled traffic in
clouds that run on jumbo-aware networks.
Change-Id: I8287677c7ad0f13fa9f5cb194f9372d04b78cb61
Related-Bug: #1527675
diff --git a/lib/neutron_plugins/ml2 b/lib/neutron_plugins/ml2
index 30e1b03..0483ef1 100644
--- a/lib/neutron_plugins/ml2
+++ b/lib/neutron_plugins/ml2
@@ -40,6 +40,12 @@
# L3 Plugin to load for ML2
ML2_L3_PLUGIN=${ML2_L3_PLUGIN:-neutron.services.l3_router.l3_router_plugin.L3RouterPlugin}
+# Underlying path MTU for physical network managing br-tun; use '-' instead of
+# ':-' to allow people to explicitly override this to blank, to disable
+# automatic MTU calculation for tunnelled tenant networks
+Q_ML2_PLUGIN_PATH_MTU=${Q_ML2_PLUGIN_PATH_MTU-1500}
+
+
function populate_ml2_config {
CONF=$1
SECTION=$2
@@ -77,6 +83,12 @@
echo "WARNING - The ml2 plugin is using local tenant networks, with no connectivity between hosts."
fi
+ # Enable ml2 mtu calculation mechanism for networks by providing path mtu
+ # value for physical devices that are used for br-tun traffic
+ if [[ "$ENABLE_TENANT_TUNNELS" == "True" ]] && [[ "$Q_ML2_PLUGIN_PATH_MTU" != "" ]]; then
+ iniset /$Q_PLUGIN_CONF_FILE ml2 path_mtu "$Q_ML2_PLUGIN_PATH_MTU"
+ fi
+
# Allow for overrding VLAN configuration (for example, to configure provider
# VLANs) by first checking if Q_ML2_PLUGIN_VLAN_TYPE_OPTIONS is set.
if [ "$Q_ML2_PLUGIN_VLAN_TYPE_OPTIONS" == "" ]; then