Change docker overlay gw MTU

Signed-off-by: gcalvino <guillermo.calvinosanchez@altran.com>
Change-Id: I43c529bfe160ed7fac032a6984ea8a3f3ea4606e
diff --git a/installers/install_osm.sh b/installers/install_osm.sh
index 2cd7b59..7cdf8bc 100755
--- a/installers/install_osm.sh
+++ b/installers/install_osm.sh
@@ -576,6 +576,11 @@
 
 function deploy_lightweight() {
     echo "Deploying lightweight build"
+    if [ "${DEFAULT_MTU}" != "1500" ]; then
+      DOCKER_NETS=`sg docker -c "docker network list" | awk '{print $2}' | egrep -v "^ID$" | paste -d " " -s`
+      DOCKER_GW_NET=`sg docker -c "docker network inspect ${DOCKER_NETS}" | grep Subnet | awk -F\" '{print $4}' | egrep "^172" | sort -u | tail -1 |  awk -F\. '{if ($2 != 255) print $1"."$2+1"."$3"."$4; else print "-1";}'`
+      sg docker -c "docker network create --subnet ${DOCKER_GW_NET} --opt com.docker.network.bridge.name=docker_gwbridge --opt com.docker.network.bridge.enable_icc=false --opt com.docker.network.bridge.enable_ip_masquerade=true --opt com.docker.network.driver.mtu=${DEFAULT_MTU} docker_gwbridge"
+    fi
     newgrp docker << EONG
     docker swarm init --advertise-addr ${DEFAULT_IP}
     docker network create --driver=overlay --attachable --opt com.docker.network.driver.mtu=${DEFAULT_MTU} netOSM