Merge "Cap the number of worker threads"

defaults/main.yml

@@ -447,6 +447,10 @@ neutron_quota_vip: 10
 # If ``neutron_metadata_workers`` is unset the system will use half the number of available VCPUs to
 # compute the number of api workers to use.
 # neutron_metadata_workers: 16
+
+## Cap the maximun number of threads / workers when a user value is unspecified.
+neutron_api_threads_max: 16
+
 neutron_metadata_backlog: 4096
 
 ## Auth

releasenotes/notes/cap-workers-fc70b4f8586ba1a5.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - The number of worker threads for neutron will now be capped at 16 unless
+    a specific value is specified. Previously, the calculated number of workers
+    could get too high on systems with a large number of processors.  This was
+    particularly evident on POWER systems.

templates/neutron.conf.j2

@@ -1,6 +1,6 @@
 # {{ ansible_managed }}
 
-{% set _api_threads = ansible_processor_vcpus|default(2) // 2 %}
+{% set _api_threads = [ansible_processor_vcpus|default(2) // 2, neutron_api_threads_max] | min %}
 {% set api_threads = _api_threads if _api_threads > 0 else 1 %}
 
 # General, applies to all host groups