When deploying with standard templates using  openstack-tripleo-heat-templates-8.3.1-12.el7ost.noarch, we hit this issue [1].

Might be related to this:
https://review.opendev.org/655628
rhbz#1699393


[1]
~~~
                                     u'deploy': {u'action': u'tripleo.deployment.deploy',
                                                 u'input': {u'container': u'<% $.container %>',
                                                            u'skip_deploy_identifier': u'<% $.skip_deploy_identifier %>',
                                                            u'timeout': u'<% $.timeout %>'},
                                                 u'name': u'deploy',
                                                 u'on-error': u'set_deployment_failed',
                                                 u'on-success': u'send_message',
                                                 u'type': u'direct',
                                                 u'version': u'2.0'},
                                     u'run_validations': {u'input': {u'group_names': [u'pre-deployment'],
                                                                     u'plan': u'<% $.container %>',
                                                                     u'queue_name': u'<% $.queue_name %>'},
                                                          u'name': u'run_validations',
                                                          u'on-error': u'set_validations_failed',
                                                          u'on-success': u'create_swift_rings_backup_plan',
                                                          u'type': u'direct',
                                                          u'version': u'2.0',
                                                          u'workflow': u'tripleo.validations.v1.run_groups'},
                                     u'send_message': {u'action': u'zaqar.queue_post',
                                                       u'input': {u'messages': {u'body': {u'payload': {u'execution': u'<% execution() %>',
                                                                                                       u'message': u"<% $.get('message', '') %>",
                                                                                                       u'status': u"<% $.get('status', 'SUCCESS') %>"},
                                                                                          u'type': u'tripleo.deployment.v1.deploy_plan'}},
                                                                  u'queue_name': u'<% $.queue_name %>'},
                                                       u'name': u'send_message',
                                                       u'on-success': [{u'fail': u'<% $.get(\'status\') = "FAILED" %>'}],
                                                       u'retry': u'count=5 delay=1',
                                                       u'type': u'direct',
                                                       u'version': u'2.0'},
                                     u'set_deployment_failed': {u'name': u'set_deployment_failed',
                                                                u'on-success': u'send_message',
                                                                u'publish': {u'message': u'<% task(deploy).result %>',
                                                                             u'status': u'FAILED'},
                                                                u'type': u'direct',
                                                                u'version': u'2.0'},
                                     u'set_validations_failed': {u'name': u'set_validations_failed',
                                                                 u'on-success': u'send_message',
                                                                 u'publish': {u'message': u'<% task(run_validations).result %>',
                                                                              u'status': u'FAILED'},
                                                                 u'type': u'direct',
                                                                 u'version': u'2.0'}},
                          u'version': u'2.0'},
                u'updated_at': u'2019-05-07 17:12:55'},
 u'message': u'Error during stack creation: ERROR: Property error: : resources.allNodesConfig.properties: : Property cellv2_discovery_hosts not assigned\nTraceback (most recent call last):\n\n  File "/usr/lib/python2.7/site-packages/heat/common/context.py", line 409, in wrapped\n    return func(self, ctx, *args, **kwargs)\n\n  File "/usr/lib/python2.7/site-packages/heat/engine/service.py", line 830, in create_stack\n    template_id)\n\n  File "/usr/lib/python2.7/site-packages/heat/engine/service.py", line 738, in _parse_template_and_validate_stack\n    stack.validate()\n\n  File "/usr/lib/python2.7/site-packages/osprofiler/profiler.py", line 158, in wrapper\n    result = f(*args, **kwargs)\n\n  File "/usr/lib/python2.7/site-packages/heat/engine/stack.py", line 902, in validate\n    result = res.validate()\n\n  File "/usr/lib/python2.7/site-packages/heat/engine/resources/template_resource.py", line 283, in validate\n    return super(TemplateResource, self).validate()\n\n  File "/usr/lib/python2.7/site-packages/heat/engine/resources/stack_resource.py", line 61, in validate\n    super(StackResource, self).validate()\n\n  File "/usr/lib/python2.7/site-packages/heat/engine/resource.py", line 1862, in validate\n    return self.validate_template()\n\n  File "/usr/lib/python2.7/site-packages/heat/engine/resource.py", line 1891, in validate_template\n    message=ex.error_message)\n\nStackValidationFailed: Property error: resources.allNodesConfig.properties: Property cellv2_discovery_hosts not assigned\n
~~~