Allow disabling of sysctl values

The main reason for this change is to allow the DinD stuff to work. It
has limited use outside of that use case, but it may still be useful
to others in the future.

Change-Id: Ib3a4639cfb3fc0d378d33fc8b9ff8eb597f818ab
Partially-Implements: blueprint multinode-gate

ansible/group_vars/all.yml

@@ -114,6 +114,9 @@ openstack_logging_debug: "False"
 
 openstack_region_name: "RegionOne"
 
+# Optionally allow Kolla to set sysctl values
+set_sysctl: "yes"
+
 # Valid options are [ novnc, spice ]
 nova_console: "novnc"
 

ansible/roles/haproxy/tasks/config.yml

@@ -17,6 +17,7 @@
 
 - name: Allowing non-local IP binding
   sysctl: name="net.ipv4.ip_nonlocal_bind" value=1 sysctl_set=yes
+  when: set_sysctl | bool
 
 - name: Ensuring config directory exists
   file:

ansible/roles/neutron/tasks/config.yml

@@ -1,14 +1,18 @@
 ---
 - name: Allowing IP forwarding on network node
   sysctl: name="net.ipv4.ip_forward" value=1 sysctl_set=yes
-  when: inventory_hostname in groups['neutron-agents']
+  when:
+    - set_sysctl | bool
+    - inventory_hostname in groups['neutron-agents']
 
 - name: Disabling reverse path filter on network node
   sysctl: name="net.ipv4.conf.{{ item }}.rp_filter" value=0 sysctl_set=yes
   with_items:
     - "all"
     - "default"
-  when: inventory_hostname in groups['neutron-agents']
+  when:
+    - set_sysctl | bool
+    - inventory_hostname in groups['neutron-agents']
 
 - include: ../../config.yml
   vars:

ansible/roles/nova/tasks/config.yml

@@ -4,14 +4,18 @@
   with_items:
     - "iptables"
     - "ip6tables"
-  when: inventory_hostname in groups['compute']
+  when:
+    - set_sysctl | bool
+    - inventory_hostname in groups['compute']
 
 - name: Disabling reverse path filter on compute node
   sysctl: name="net.ipv4.conf.{{ item }}.rp_filter" value=0 sysctl_set=yes
   with_items:
     - "all"
     - "default"
-  when: inventory_hostname in groups['neutron-agents']
+  when:
+    - set_sysctl | bool
+    - inventory_hostname in groups['neutron-agents']
 
 - include: ../../config.yml
   vars: