Control amount of metricd workers

As of today we didn't manage amount of gnocchi-metricd that equal to
amount of CPU on host. So things can go off regarding CPU and memory
consumption. For better control of ressources we add a variable to
control the number of workers.

Change-Id: Idcaec649a4de03f5714c61fda694ada45da41dbc

defaults/main.yml

@@ -139,6 +139,9 @@ gnocchi_wsgi_threads: 1
 gnocchi_wsgi_processes_max: 16
 gnocchi_wsgi_processes: "{{ [[(ansible_facts['processor_vcpus']//ansible_facts['processor_threads_per_core'])|default(1), 1] | max * 2, gnocchi_wsgi_processes_max] | min }}"
 
+gnocchi_metricd_workers_max: 16
+gnocchi_metricd_workers: "{{ [[(ansible_facts['processor_vcpus']//ansible_facts['processor_threads_per_core'])|default(1), 1] | max * 2, gnocchi_metricd_workers_max] | min }}"
+
 gnocchi_uwsgi_conf_overrides: {}
 gnocchi_api_init_overrides: {}
 gnocchi_metricd_init_overrides: {}

releasenotes/notes/gnocchi_metricd_workers-e179af4e37d1531d.yaml

@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    Implemented variable ``gnocchi_metricd_workers`` that is designed to
+    controll amount of gnocchi-metricd workers spawned. By default it is
+    equal to number of CPU cores, but no more than 16 workers.
+

templates/gnocchi.conf.j2

@@ -124,7 +124,7 @@ redis_url = {{ gnocchi_incoming_redis_url }}
 # Number of workers for Gnocchi metric daemons. By default the available number
 # of CPU is used. (integer value)
 # Minimum value: 1
-#workers = 1
+workers = {{ gnocchi_metricd_workers }}
 
 [statsd]
 # The listen IP for statsd (string value)