OVB: use "ipmi" driver instead of "pxe_ipmitool" for >= Queens

The classic drivers (pxe_*, agent_* and iscsi_*) are deprecated in
Queens and will be removed in Rocky. This change uses the new
--driver argument to build-nodes-json to specify the driver to use.

Change-Id: If51505c4cd53918200b65c75915e389adaddb200

roles/ovb-manage-stack/README.md

@@ -56,6 +56,9 @@ Parameters used the env.yaml file to create the OVB heat stack (See defaults/mai
 
 - registered_releases -- releases for which images should be available for the undercloud
 
+- baremetal_driver -- ironic driver to use for overcloud nodes, 'pxe_ipmitool'
+  for < Queens, 'ipmi' for >= Queens
+
 Dependencies
 ------------
 

roles/ovb-manage-stack/defaults/main.yml

@@ -92,6 +92,13 @@ registered_releases:
   - rhos-11
   - rhos-12
 
+baremetal_driver: >-
+    {% if release not in ['newton', 'ocata', 'pike'] -%}
+    "ipmi"
+    {%- else -%}
+    "pxe_ipmitool"
+    {%- endif -%}
+
 # OVB environment clean up
 cleanup_stacks_keypairs: false
 cleanup_stacks_keypairs_script: cleanup-stacks-keypairs.sh.j2

roles/ovb-manage-stack/tasks/ovb-create-stack.yml

@@ -180,7 +180,7 @@
       chdir={{ local_working_dir }}
       export OS_CLIENT_CONFIG_FILE="{{ local_working_dir }}/clouds.yaml";
       export OS_CLOUD="{{ cloud_name}}";
-      {{ ovb_dir }}/bin/build-nodes-json --env {{ local_working_dir }}/{{ prefix }}env.yaml
+      {{ ovb_dir }}/bin/build-nodes-json --env {{ local_working_dir }}/{{ prefix }}env.yaml --driver {{ baremetal_driver }}
   register: nodes_json
 
 - name: remove clouds.yaml file