Add option to disable lxc interface management

This change adds a new role default option which will allow operators
to omit the deployment of specific lxc bridge network config. This
change is being implemented because, as an operator, I have a host
setup specifically built for OpenStack which includes an interface
config covering the lxc deployment. Currently when running a deployment
the role will attempt to deploy a new interface file which at best
conflicts with the host setup and at worst fails to run due to the
interface being in a state unknown to OSA.

The new config option `lxc_net_managed` is default **true** keeping
the existing expectations, but when set to **false** the role will
no longer deploy an interface file or attempt to bring up the interface
using the distro tools.

Signed-off-by: Kevin Carter <kevin@cloudnull.com>
Change-Id: Icdf4a1f5ff98dc1b86c6a87ea4e606b7c74e1aac

defaults/main.yml

@@ -95,6 +95,9 @@ lxc_container_base_name: "{{ lxc_cache_map.distro }}-{{ lxc_cache_map.release }}
 # Set the default zfs root name
 lxc_container_zfs_root_name: "pool/lxc"
 
+# Allow OSA to generate the LXC network configuration and manage the interface state.
+lxc_net_managed: true
+
 # lxc container net network
 lxc_net_bridge: lxcbr0
 lxc_net_bridge_port: none

releasenotes/notes/lxc_net_managed-7a898d07c240b424.yaml

@@ -0,0 +1,8 @@
+---
+features:
+  - |
+    The lxc_hosts role now supports the ability to omit lxc network
+    interface deployment. The option `lxc_net_managed` is a Boolean
+    operator and defaults to **true**. When this option is set to
+    **false** the role will not deploy an interface file or attempt
+    to manage the state of the interface.

tasks/main.yml

@@ -75,6 +75,8 @@
     - lxc_hosts-config
 
 - include_tasks: lxc_net.yml
+  when:
+    - lxc_net_managed | bool
   tags:
     - lxc_hosts-config