Add openstack_node_role parameter

Add openstack_node_role parameter that will specify node role
primary|secondary. This metadata will be used by formulas as a
trigger to run one-shot operations.

Change-Id: I230590bc5f9d53960c6edaf7e37c44541d9c3342
Related-Prod: PROD-21267
diff --git a/octavia/api/single.yml b/octavia/api/single.yml
index a9d30a5..ff76e76 100644
--- a/octavia/api/single.yml
+++ b/octavia/api/single.yml
@@ -6,6 +6,7 @@
   octavia:
     api:
       enabled: true
+      role: ${_param:openstack_node_role}
       bind:
         address: ${_param:single_address}
       database: