Calico is not a network overlay

roles/overlay_network/tasks/main.yml

----
-- name: "Test if overlay network is defined"
-  fail: msg="ERROR, One overlay_network variable must be defined (Flannel or Calico)"
-  when: ( overlay_network_plugin is defined and overlay_network_plugin == "calico" and overlay_network_plugin == "flannel" ) or
-        overlay_network_plugin is not defined 
-
-- include: flannel.yml
-  when: overlay_network_plugin == "flannel"
-- include: calico.yml
-  when: overlay_network_plugin == "calico"
-
-- meta: flush_handlers
-

roles/overlay_network/templates/flannel/flannel-conf.json.j2

-{ "Network": "{{ kube_service_addresses }}", "SubnetLen": {{ overlay_network_host_prefix }}, "Backend": { "Type": "vxlan" } }