Allow configureable vni and port for flannel overlay (#5939)

inventory/sample/group_vars/k8s-cluster/k8s-net-flannel.yml

@@ -14,3 +14,5 @@
 # for experimental backend
 # please refer to flannel's docs : https://github.com/coreos/flannel/blob/master/README.md
 # flannel_backend_type: "vxlan"
+# flannel_vxlan_vni: 1
+# flannel_vxlan_port: 8472

roles/network_plugin/flannel/defaults/main.yml

@@ -17,6 +17,8 @@
 # You can choose what type of flannel backend to use
 # please refer to flannel's docs : https://github.com/coreos/flannel/blob/master/README.md
 flannel_backend_type: "vxlan"
+flannel_vxlan_vni: 1
+flannel_vxlan_port: 8472
 
 # Limits for apps
 flannel_memory_limit: 500M

roles/network_plugin/flannel/templates/cni-flannel.yml.j2

@@ -32,7 +32,10 @@ data:
     {
       "Network": "{{ kube_pods_subnet }}",
       "Backend": {
-        "Type": "{{ flannel_backend_type }}"
+        "Type": "{{ flannel_backend_type }}"{% if flannel_backend_type == "vxlan" %},
+        "VNI": {{ flannel_vxlan_vni }},
+        "Port": {{ flannel_vxlan_port }}
+{% endif %}
       }
     }
 ---