Control amount of conductor workers

As of today we didn't manage amount of magnum-conductors that equal to
amount of CPU on host. So things can go off regarding CPU and memory
consumption. For better control on resources we add variable to control
conductor workers.

Depends-On: https://review.opendev.org/c/openstack/openstack-ansible/+/846151
Change-Id: I3eedd74717b3b621b4e0b6ae4a8df4ee6f1eb739

defaults/main.yml

@@ -225,3 +225,7 @@ magnum_wsgi_processes_max: 16
 magnum_wsgi_processes: "{{ [[(ansible_facts['processor_vcpus']//ansible_facts['processor_threads_per_core'])|default(1), 1] | max * 2, magnum_wsgi_processes_max] | min }}"
 magnum_wsgi_threads: 1
 magnum_api_uwsgi_bind_address: "{{ openstack_service_bind_address | default('0.0.0.0') }}"
+
+# conductor settings
+magnum_conductor_workers_max: 16
+magnum_conductor_workers: "{{ [[(ansible_facts['processor_vcpus']//ansible_facts['processor_threads_per_core'])|default(1), 1] | max * 2, magnum_conductor_workers_max] | min }}"

releasenotes/notes/magnum_conductor_workers-3f7eafeb4429dd0b.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    Implemented variable ``magnum_conductor_workers`` that is designed to
+    controll amount of magnum-conductor workers spawned. By default it is
+    equal to number of CPU cores, but no more then 16 workers.

templates/magnum.conf.j2

@@ -22,6 +22,9 @@ endpoint_type = internalURL
 region_name = {{ magnum_cinder_service_region }}
 endpoint_type = internalURL
 
+[conductor]
+workers = {{ magnum_conductor_workers }}
+
 [database]
 connection = mysql+pymysql://{{ magnum_galera_user }}:{{ magnum_galera_password }}@{{ magnum_galera_address }}/{{ magnum_galera_database_name }}?charset=utf8{% if magnum_galera_use_ssl | bool %}&ssl_verify_cert=true{% if magnum_galera_ssl_ca_cert | length > 0 %}&ssl_ca={{ magnum_galera_ssl_ca_cert }}{% endif %}{% endif +%}
 max_overflow = {{ magnum_db_max_overflow }}