Merge pull request kubernetes#19642 from MikeSpreitzer/issue/19618

Introduce FLANNEL_OTHER_NET_CONFIG

cluster/ubuntu/config-default.sh

@@ -34,6 +34,15 @@ export SERVICE_CLUSTER_IP_RANGE=${SERVICE_CLUSTER_IP_RANGE:-192.168.3.0/24}  # f
 # define the IP range used for flannel overlay network, should not conflict with above SERVICE_CLUSTER_IP_RANGE
 export FLANNEL_NET=${FLANNEL_NET:-172.16.0.0/16}
 
+# Optionally add other contents to the Flannel configuration JSON
+# object normally stored in etcd as /coreos.com/network/config.  Use
+# JSON syntax suitable for insertion into a JSON object constructor
+# after other field name:value pairs.  For example:
+# FLANNEL_OTHER_NET_CONFIG=', "SubnetMin": "172.16.10.0", "SubnetMax": "172.16.90.0"'
+
+export FLANNEL_OTHER_NET_CONFIG
+FLANNEL_OTHER_NET_CONFIG=''
+
 # Admission Controllers to invoke prior to persisting objects in cluster
 export ADMISSION_CONTROL=NamespaceLifecycle,LimitRanger,ServiceAccount,ResourceQuota,SecurityContextDeny
 

cluster/ubuntu/reconfDocker.sh

@@ -36,7 +36,7 @@ function config_etcd {
         exit 2
       fi
 
-      /opt/bin/etcdctl mk /coreos.com/network/config "{\"Network\":\"${FLANNEL_NET}\", \"Backend\": {\"Type\": \"vxlan\"}}"
+      /opt/bin/etcdctl mk /coreos.com/network/config "{\"Network\":\"${FLANNEL_NET}\", \"Backend\": {\"Type\": \"vxlan\"}${FLANNEL_OTHER_NET_CONFIG}}"
       attempt=$((attempt+1))
       sleep 3
     fi

cluster/ubuntu/util.sh

@@ -396,7 +396,7 @@ function provision-master() {
     create-kube-controller-manager-opts '${NODE_IPS}'
     create-kube-scheduler-opts
     create-flanneld-opts '127.0.0.1' '${MASTER_IP}'
-    sudo -E -p '[sudo] password to start master: ' -- /bin/bash -ce '
+    FLANNEL_OTHER_NET_CONFIG='${FLANNEL_OTHER_NET_CONFIG}' sudo -E -p '[sudo] password to start master: ' -- /bin/bash -ce '
       ${BASH_DEBUG_FLAGS}
 
       cp ~/kube/default/* /etc/default/
@@ -529,7 +529,7 @@ function provision-masterandnode() {
       '${MASTER_IP}'
     create-flanneld-opts '127.0.0.1' '${MASTER_IP}'
 
-    sudo -E -p '[sudo] password to start master: ' -- /bin/bash -ce ' 
+    FLANNEL_OTHER_NET_CONFIG='${FLANNEL_OTHER_NET_CONFIG}' sudo -E -p '[sudo] password to start master: ' -- /bin/bash -ce ' 
       ${BASH_DEBUG_FLAGS}
       cp ~/kube/default/* /etc/default/
       cp ~/kube/init_conf/* /etc/init/

docs/getting-started-guides/ubuntu.md

@@ -145,6 +145,8 @@ that conflicts with your own private network range.
 
 The `FLANNEL_NET` variable defines the IP range used for flannel overlay network,
 should not conflict with above `SERVICE_CLUSTER_IP_RANGE`.
+You can optionally provide additional Flannel network configuration
+through `FLANNEL_OTHER_NET_CONFIG`, as explained in `cluster/ubuntu/config-default.sh`.
 
 **Note:** When deploying, master needs to be connected to the Internet to download the necessary files.
 If your machines are located in a private network that need proxy setting to connect the Internet,