Add user defined hooks that can run extra playbooks

This patch adds variables which when can be used to extend
openstack ansible by calling additional user defined playbooks
at the start and end of the main setup-* playbooks.

Change-Id: Ic55dd6447f603d91beaeea28beb04e4c1393d6af

playbooks/hook-dummy.yml

@@ -0,0 +1,3 @@
+- name: Placeholder hook
+  hosts: localhost
+  gather_facts: false

playbooks/setup-hosts.yml

@@ -13,6 +13,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+- name: Importing pre hook playbook
+  import_playbook: "{{ pre_setup_hosts_hook | default('hook-dummy.yml') }}"
+
 - name: Importing certificate-authority playbook
   import_playbook: certificate-authority.yml
 
@@ -30,3 +33,6 @@
 
 - name: Importing security-hardening playbook
   import_playbook: security-hardening.yml
+
+- name: Importing post hook playbook
+  import_playbook: "{{ post_setup_hosts_hook | default('hook-dummy.yml') }}"

playbooks/setup-infrastructure.yml

@@ -13,6 +13,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+- name: Importing pre hook playbook
+  import_playbook: "{{ pre_setup_infrastructure_hook | default('hook-dummy.yml') }}"
+
 - name: Importing unbound-install playbook
   import_playbook: unbound-install.yml
 
@@ -52,3 +55,6 @@
 - name: Importing infra-journal-remote playbook
   import_playbook: infra-journal-remote.yml
   when: journald_remote_enabled | default (false) | bool
+
+- name: Importing post hook playbook
+  import_playbook: "{{ post_setup_infrastructure_hook | default('hook-dummy.yml') }}"

playbooks/setup-openstack.yml

@@ -13,6 +13,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+- name: Importing pre hook playbook
+  import_playbook: "{{ pre_setup_openstack_hook | default('hook-dummy.yml') }}"
+
 - name: Importing os-keystone-install playbook
   import_playbook: os-keystone-install.yml
 
@@ -110,3 +113,6 @@
 
 - name: Importing os-rally-install playbook
   import_playbook: os-rally-install.yml
+
+- name: Importing post hook playbook
+  import_playbook: "{{ post_setup_openstack_hook | default('hook-dummy.yml') }}"

releasenotes/notes/hook-playbooks-b71dbdd7835af2aa.yaml

@@ -0,0 +1,8 @@
+---
+features:
+  - |
+    New variables are added to allow a user defined playbooks to be specified
+    that run pre and post the existing code in setup-hosts, setup-infrastructure
+    and setup-openstack. OpenStack-Ansible deployments may be extended and
+    have additional user defined functions added using these hooks, which
+    will have full access to the OSA inventory and host variables.