CephStorageNodesPostDeployment fails with "Deployment exited with non-zero status code: 6"

Issue

• Installation of overcloud fails with an error:

[stack@instack ~]$ openstack overcloud deploy --compute-scale 1 --control-scale 3 --ceph-storage-scale 3 --templates  -e /usr/share/openstack-tripleo-heat-templates/environments/network-isolation.yaml -e /home/stack/network-environment.yaml --control-flavor control --compute-flavor compute --ceph-storage-flavor ceph
Deploying templates in the directory /usr/share/openstack-tripleo-heat-templates
ERROR: openstack Heat Stack create failed.

• From heat resource-list overcloud:

[stack@instack ~]$ heat resource-list overcloud
+-----------------------------------+-----------------------------------------------+---------------------------------------------------+-----------------+----------------------+
| resource_name                     | physical_resource_id                          | resource_type                                     | resource_status | updated_time         |
+-----------------------------------+-----------------------------------------------+---------------------------------------------------+-----------------+----------------------+
| BlockStorage                      | d2bea500-8258-4181-807a-8e6c64f4a208          | OS::Heat::ResourceGroup                           | CREATE_COMPLETE | 2015-09-09T08:38:58Z |
| BlockStorageAllNodesDeployment    | 71fcfc09-c521-485d-80e0-a075b282d2d1          | OS::Heat::StructuredDeployments                   | CREATE_COMPLETE | 2015-09-09T08:38:58Z |
| BlockStorageNodesPostDeployment   | 74711015-742e-49d1-876c-06f5ec174c76          | OS::TripleO::BlockStoragePostDeployment           | CREATE_COMPLETE | 2015-09-09T08:38:58Z |
| CephClusterConfig                 | 204ee711-0750-471e-a0c7-110f667f0b10          | OS::TripleO::CephClusterConfig::SoftwareConfig    | CREATE_COMPLETE | 2015-09-09T08:38:58Z |
| CephStorage                       | 4224f7e9-203d-4853-a040-a82d870e5690          | OS::Heat::ResourceGroup                           | CREATE_COMPLETE | 2015-09-09T08:38:58Z |
| CephStorageAllNodesDeployment     | ea9cc94c-9c28-437b-b2a3-5df693c48270          | OS::Heat::StructuredDeployments                   | CREATE_COMPLETE | 2015-09-09T08:38:58Z |
| CephStorageCephDeployment         | 761d9742-02cd-434d-932b-9868f13bc886          | OS::Heat::StructuredDeployments                   | CREATE_COMPLETE | 2015-09-09T08:38:58Z |
| CephStorageNodesPostDeployment    | 805ddf92-b570-407d-846e-c8f71e0a829d          | OS::TripleO::CephStoragePostDeployment            | CREATE_FAILED   | 2015-09-09T08:38:58Z |  <====
| Compute                           | 3a388db6-90c2-4236-9ba5-7a2a5c5235eb          | OS::Heat::ResourceGroup                           | CREATE_COMPLETE | 2015-09-09T08:38:58Z |
| ComputeAllNodesDeployment         | 8ed2783d-2b63-483a-8e42-871cbe417adc          | OS::Heat::StructuredDeployments                   | CREATE_COMPLETE | 2015-09-09T08:38:58Z |
| ComputeCephDeployment             | e4171920-20dc-49f9-bea2-ce57de5e2f9a          | OS::Heat::StructuredDeployments                   | CREATE_COMPLETE | 2015-09-09T08:38:58Z |
| ComputeNodesPostDeployment        | e6e5b705-b7ad-4ff5-8880-4e02cdb70d43          | OS::TripleO::ComputePostDeployment                | CREATE_COMPLETE | 2015-09-09T08:38:58Z |
| ControlVirtualIP                  | fb2d859a-bf2e-4c83-ab48-f37562b7b291          | OS::Neutron::Port                                 | CREATE_COMPLETE | 2015-09-09T08:38:58Z |
| Controller                        | 77fb1af7-850d-41c6-ae2e-9a6c1dd1b856          | OS::Heat::ResourceGroup                           | CREATE_COMPLETE | 2015-09-09T08:38:58Z |
| ControllerAllNodesDeployment      | a34d3607-5ce7-4f71-b809-a89401ff9a13          | OS::Heat::StructuredDeployments                   | CREATE_COMPLETE | 2015-09-09T08:38:58Z |
| ControllerBootstrapNodeConfig     | 8904e9e6-e7fe-4440-85a9-540ba29c086b          | OS::TripleO::BootstrapNode::SoftwareConfig        | CREATE_COMPLETE | 2015-09-09T08:38:58Z |
| ControllerBootstrapNodeDeployment | a4e40c9a-25e2-4010-a206-0811714da3b4          | OS::Heat::StructuredDeployments                   | CREATE_COMPLETE | 2015-09-09T08:38:58Z |
[...]

• From heat-engine.log:

2015-09-09 05:10:49.044 15998 INFO heat.engine.resource [-] CREATE: OS::TripleO::CephStoragePostDeployment "CephStorageNodesPostDeployment" [805ddf92-b570-407d-846e-c8f71e0a829d] Stack "over
cloud" [fd86d026-ad46-4226-90f5-3671ff2e1d11]
2015-09-09 05:10:49.044 15998 TRACE heat.engine.resource Traceback (most recent call last):
2015-09-09 05:10:49.044 15998 TRACE heat.engine.resource   File "/usr/lib/python2.7/site-packages/heat/engine/resource.py", line 500, in _action_recorder
2015-09-09 05:10:49.044 15998 TRACE heat.engine.resource     yield
2015-09-09 05:10:49.044 15998 TRACE heat.engine.resource   File "/usr/lib/python2.7/site-packages/heat/engine/resource.py", line 570, in _do_action
2015-09-09 05:10:49.044 15998 TRACE heat.engine.resource     yield self.action_handler_task(action, args=handler_args)
2015-09-09 05:10:49.044 15998 TRACE heat.engine.resource   File "/usr/lib/python2.7/site-packages/heat/engine/scheduler.py", line 313, in wrapper
2015-09-09 05:10:49.044 15998 TRACE heat.engine.resource     step = next(subtask)
2015-09-09 05:10:49.044 15998 TRACE heat.engine.resource   File "/usr/lib/python2.7/site-packages/heat/engine/resource.py", line 544, in action_handler_task
2015-09-09 05:10:49.044 15998 TRACE heat.engine.resource     while not check(handler_data):
2015-09-09 05:10:49.044 15998 TRACE heat.engine.resource   File "/usr/lib/python2.7/site-packages/heat/engine/resources/stack_resource.py", line 281, in check_create_complete
2015-09-09 05:10:49.044 15998 TRACE heat.engine.resource     return self._check_status_complete(resource.Resource.CREATE)
2015-09-09 05:10:49.044 15998 TRACE heat.engine.resource   File "/usr/lib/python2.7/site-packages/heat/engine/resources/stack_resource.py", line 324, in _check_status_complete
2015-09-09 05:10:49.044 15998 TRACE heat.engine.resource     status_reason=nested.status_reason)
2015-09-09 05:10:49.044 15998 TRACE heat.engine.resource ResourceUnknownStatus: Resource failed - Unknown status FAILED due to "Resource CREATE failed: ResourceUnknownStatus: Resource failed
 - Unknown status FAILED due to "Resource CREATE failed: Error: Deployment to server failed: deploy_status_code : Deployment exited with non-zero status code: 6""