Add cilium_tunnel_mode variable to the cilium config (#5295)

roles/network_plugin/cilium/defaults/main.yml

@@ -17,6 +17,8 @@ cilium_cpu_limit: 500m
 cilium_memory_requests: 64M
 cilium_cpu_requests: 100m
 
+# Overlay Network Mode
+cilium_tunnel_mode: vxlan
 # Optional features
 cilium_enable_prometheus: false
 # Enable if you want to make use of hostPort mappings

roles/network_plugin/cilium/templates/cilium-config.yml.j2

@@ -104,7 +104,7 @@ data:
   #   - disabled
   #   - vxlan (default)
   #   - geneve
-  tunnel: "vxlan"
+  tunnel: "{{ cilium_tunnel_mode }}"
 
   # Name of the cluster. Only relevant when building a mesh of clusters.
   cluster-name: default