Allow user sysctl list

Let operators feed the role a list of sysctl settings to set without
overriding the default openstack_kernel_options list.

Change-Id: I148492e691e552add6787fdc3937e65bd1366772
(cherry picked from commit f5caf08)

defaults/main.yml

@@ -90,5 +90,9 @@ openstack_kernel_options:
   - { key: 'net.ipv6.neigh.default.gc_stale_time', value: 120 }
   - { key: 'fs.aio-max-nr', value: 131072 }
 
+# Optional user defined list of sysctl options in the same dict item format as
+# above.
+openstack_user_kernel_options: []
+
 # Set the openstack domain name
 openstack_domain: openstack.local

tasks/openstack_kernel_tuning.yml

@@ -20,5 +20,5 @@
     sysctl_set: "{{ item.set|default('yes') }}"
     state: "{{ item.state|default('present') }}"
     reload: "{{ item.reload|default('yes') }}"
-  with_items: "{{ openstack_kernel_options }}"
+  with_items: "{{ openstack_kernel_options + openstack_user_kernel_options }}"
   failed_when: false