Make number of Octavia controller workers configurable

Also increase default number of workers to 2.

Related-PROD: PROD-34519

(cherry-pick from commit 453068bde9cf3c4c2f9cdb5e9da69cd50d5e1423)

Change-Id: Ic5cf197e5486a9a0e172a5fbf5b8b6c787935e3f
diff --git a/metadata/service/manager/single.yml b/metadata/service/manager/single.yml
index c976a24..a4fd56d 100644
--- a/metadata/service/manager/single.yml
+++ b/metadata/service/manager/single.yml
@@ -6,6 +6,7 @@
   _param:
     keystone_octavia_endpoint_type: internal
     octavia_loadbalancer_topology: 'SINGLE'
+    octavia_controller_worker_number: 2
     octavia_hm_bind_port: 5555
     octavia_amphora_availability_zone: 'nova'
     octavia_worker_connection_max_retries: 500
@@ -42,6 +43,7 @@
         ca_private_key: '/etc/octavia/certs/ca.key'
         ca_certificate: '/etc/octavia/certs/ca_01.pem'
       controller_worker:
+        workers: ${_param:octavia_controller_worker_number}
         amp_flavor_id: ${_param:amp_flavor_id}
         amp_image_tag: amphora
         amp_ssh_key_name: octavia_ssh_key