Create ceph python library symlinks

Currently, os_nova, os_cinder, and os_glance roles all install
python-cephlibs, which is a python package Hugh Saunders created for
Ceph Hammer python libraries.  The virtualenvs created in these roles
need access to these python libraries and by using Hugh's python
package we could simply pip install into the virtualenv.

This has been working fine, but makes the assumption that the deployer
is using Ceph Hammer, which may not be true.  Also, later versions of
Ceph have python C extensions, which may be more difficult to package.

This commit simply leverages the existing Ceph libraries installed
outside of the venv by checking for the path of the library using
python itself.

NOTE: I would prefer to use a None instead of '' in the ternaries,
but seem to hit issues doing that.

Combined backport of:
- https://review.openstack.org/#/c/317901/
- https://review.openstack.org/#/c/339619/

Change-Id: Ib26c84f6671523b40e61f043713db58d8a756dc9

playbooks/os-cinder-install.yml

@@ -194,7 +194,9 @@
       tags:
         - "os-cinder"
     - role: "ceph_client"
+      cinder_venv_bin: "/openstack/venvs/cinder-{{ openstack_release }}/bin"
       openstack_service_system_user: "{{ cinder_system_user_name }}"
+      openstack_service_venv_bin: "{{ cinder_venv_bin if cinder_venv_enabled|default(True)|bool else None }}"
       tags:
         - "cinder-ceph-client"
         - "ceph-client"

playbooks/os-glance-install.yml

@@ -128,7 +128,9 @@
         - "os-glance"
     - { role: "openstack_openrc", tags: [ "openstack-openrc" ] }
     - role: "ceph_client"
+      glance_venv_bin: "/openstack/venvs/glance-{{ openstack_release }}/bin"
       openstack_service_system_user: "{{ glance_system_user_name }}"
+      openstack_service_venv_bin: "{{ glance_venv_bin if glance_venv_enabled|default(True)|bool else None }}"
       tags:
         - "glance-ceph-client"
         - "ceph-client"

playbooks/os-nova-install.yml

@@ -200,7 +200,9 @@
       tags:
         - "os-nova"
     - role: "ceph_client"
+      nova_venv_bin: "/openstack/venvs/nova-{{ openstack_release }}/bin"
       openstack_service_system_user: "{{ nova_system_user_name }}"
+      openstack_service_venv_bin: "{{ nova_venv_bin if nova_venv_enabled|default(True)|bool else None }}"
       tags:
         - "nova-ceph-client"
         - "ceph-client"

playbooks/roles/ceph_client/tasks/ceph_all.yml

@@ -28,6 +28,11 @@
 - include:  ceph_install.yml
   tags:     ceph-install
 
+- include: ceph_install_python_libs.yml
+  when: openstack_service_venv_bin != ''
+  tags:
+    - ceph-install
+
 - include: ceph_get_mon_host.yml
   tags:
     - ceph-config

playbooks/roles/ceph_client/tasks/ceph_install_python_libs.yml

@@ -0,0 +1,44 @@
+---
+# Copyright 2014, Rackspace US, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+- name: Register rados module path
+  command: python -c 'import rados; print rados.__file__'
+  register: rados_module_path
+  tags:
+    - ceph-python-libs
+
+- name: Register rbd module path
+  command: python -c 'import rbd; print rbd.__file__'
+  register: rbd_module_path
+  tags:
+    - ceph-python-libs
+
+- name: Link rados module into the venv
+  file:
+    src: "{{ rados_module_path.stdout }}"
+    dest: "{{ openstack_service_venv_bin | dirname }}/lib/python2.7/site-packages/{{ rados_module_path.stdout | basename }}"
+    state: link
+    force: "yes"
+  tags:
+    - ceph-python-libs
+
+- name: Link rbd module into the venv
+  file:
+    src: "{{ rbd_module_path.stdout }}"
+    dest: "{{ openstack_service_venv_bin | dirname }}/lib/python2.7/site-packages/{{ rbd_module_path.stdout | basename }}"
+    state: link
+    force: "yes"
+  tags:
+    - ceph-python-libs