cinder: Define backend variables in group_vars/all

The iscsi role derives the cinder-volume/backup inventory groups from
cinder_enabled_backends, but that variable (along with cinder_backends,
cinder_ceph_backends and the cinder_backend_*_name variables) was only
defined in the cinder role defaults. The iscsi play runs before the
cinder play, so the variable is out of scope there and prechecks (and
deploy/reconfigure) fail with:

    'cinder_enabled_backends' is undefined

when a Cinder iSCSI/LVM backend is enabled.

Move these backend variable definitions to group_vars/all/cinder.yml so
they are in scope for every play, including the iscsi role. This also
keeps all cinder backend definitions - including the cinder-backup ceph
backend (cinder_backup_backend_ceph_name, cinder_backup_ceph_backend) -
in one place. All of their dependencies (the enable_cinder_backend_*
flags, cinder_backend_ceph and the ceph_* variables) are already global,
and globals.yml is applied as extra-vars, so operator overrides continue
to take precedence.

Partial-Bug: #2158120
Change-Id: I765f45814382377332ba9f01f1bc52bd4e046170
Signed-off-by: Kari Häkkinen <Kari.Hakkinen@admicom.com>
(cherry picked from commit 2df2ee6e49d0fd58b1781c0b490b019e1936e96b)

3 files changed, 72 insertions, 50 deletions

diff --git a/ansible/group_vars/all/cinder.yml b/ansible/group_vars/all/cinder.yml
index 9418adcc9..a11b19dd8 100644
--- a/ansible/group_vars/all/cinder.yml
+++ b/ansible/group_vars/all/cinder.yml
@@ -12,6 +12,63 @@ enable_cinder_backend_pure_nvme_tcp: false
 enable_cinder_backend_lightbits: false
 
 #################################
+# Cinder backends
+#################################
+# NOTE: These are defined here (rather than in the cinder role defaults) so that
+# they are in scope for other roles - notably iscsi, whose play runs before the
+# cinder play and derives the cinder-volume/backup inventory groups from
+# cinder_enabled_backends.
+cinder_backend_ceph_name: "rbd-1"
+cinder_backend_lvm_name: "lvm-1"
+cinder_backend_nfs_name: "nfs-1"
+cinder_backend_quobyte_name: "QuobyteHD"
+cinder_backend_pure_iscsi_name: "Pure-FlashArray-iscsi"
+cinder_backend_pure_fc_name: "Pure-FlashArray-fc"
+cinder_backend_pure_roce_name: "Pure-FlashArray-roce"
+cinder_backend_pure_nvme_tcp_name: "Pure-FlashArray-nvme-tcp"
+cinder_backend_lightbits_name: "Lightbits-NVMe-TCP"
+
+cinder_backends:
+  - name: "{{ cinder_backend_lvm_name }}"
+    enabled: "{{ enable_cinder_backend_lvm | bool }}"
+  - name: "{{ cinder_backend_nfs_name }}"
+    enabled: "{{ enable_cinder_backend_nfs | bool }}"
+  - name: "{{ cinder_backend_quobyte_name }}"
+    enabled: "{{ enable_cinder_backend_quobyte | bool }}"
+  - name: "{{ cinder_backend_pure_iscsi_name }}"
+    enabled: "{{ enable_cinder_backend_pure_iscsi | bool }}"
+  - name: "{{ cinder_backend_pure_fc_name }}"
+    enabled: "{{ enable_cinder_backend_pure_fc | bool }}"
+  - name: "{{ cinder_backend_pure_roce_name }}"
+    enabled: "{{ enable_cinder_backend_pure_roce | bool }}"
+  - name: "{{ cinder_backend_pure_nvme_tcp_name }}"
+    enabled: "{{ enable_cinder_backend_pure_nvme_tcp | bool }}"
+  - name: "{{ cinder_backend_lightbits_name }}"
+    enabled: "{{ enable_cinder_backend_lightbits | bool }}"
+
+cinder_ceph_backends:
+  - name: "{{ cinder_backend_ceph_name }}"
+    backend_name: "{{ cinder_backend_ceph_name }}"
+    cluster: "{{ ceph_cluster }}"
+    user: "{{ ceph_cinder_user }}"
+    pool: "{{ ceph_cinder_pool_name }}"
+    enabled: "{{ cinder_backend_ceph | bool }}"
+
+cinder_backup_backend_ceph_name: "rbd-1"
+cinder_backup_ceph_backend: >-
+  {{
+    cinder_ceph_backends |
+    selectattr('name', 'equalto', cinder_backup_backend_ceph_name) | list | first |
+    combine({'pool': ceph_cinder_backup_pool_name, 'user': ceph_cinder_backup_user})
+  }}
+
+cinder_enabled_backends: >-
+  {{
+    cinder_backends | selectattr('enabled', 'equalto', true) | list
+    + cinder_ceph_backends | selectattr('enabled', 'equalto', true) | list
+  }}
+
+#################################
 # Cinder options
 #################################
 cinder_backend_ceph: false
diff --git a/ansible/roles/cinder/defaults/main.yml b/ansible/roles/cinder/defaults/main.yml
index 37f7f7aab..c1f051c97 100644
--- a/ansible/roles/cinder/defaults/main.yml
+++ b/ansible/roles/cinder/defaults/main.yml
@@ -253,58 +253,13 @@ cinder_api_workers: "{{ openstack_service_workers }}"
 ####################
 # Cinder
 ####################
-cinder_backends:
-  - name: "{{ cinder_backend_lvm_name }}"
-    enabled: "{{ enable_cinder_backend_lvm | bool }}"
-  - name: "{{ cinder_backend_nfs_name }}"
-    enabled: "{{ enable_cinder_backend_nfs | bool }}"
-  - name: "{{ cinder_backend_quobyte_name }}"
-    enabled: "{{ enable_cinder_backend_quobyte | bool }}"
-  - name: "{{ cinder_backend_pure_iscsi_name }}"
-    enabled: "{{ enable_cinder_backend_pure_iscsi | bool }}"
-  - name: "{{ cinder_backend_pure_fc_name }}"
-    enabled: "{{ enable_cinder_backend_pure_fc | bool }}"
-  - name: "{{ cinder_backend_pure_roce_name }}"
-    enabled: "{{ enable_cinder_backend_pure_roce | bool }}"
-  - name: "{{ cinder_backend_pure_nvme_tcp_name }}"
-    enabled: "{{ enable_cinder_backend_pure_nvme_tcp | bool }}"
-  - name: "{{ cinder_backend_lightbits_name }}"
-    enabled: "{{ enable_cinder_backend_lightbits | bool }}"
-
-cinder_backend_ceph_name: "rbd-1"
-cinder_backend_lvm_name: "lvm-1"
-cinder_backend_nfs_name: "nfs-1"
-cinder_backend_quobyte_name: "QuobyteHD"
-cinder_backend_pure_iscsi_name: "Pure-FlashArray-iscsi"
-cinder_backend_pure_fc_name: "Pure-FlashArray-fc"
-cinder_backend_pure_roce_name: "Pure-FlashArray-roce"
-cinder_backend_pure_nvme_tcp_name: "Pure-FlashArray-nvme-tcp"
-cinder_backend_lightbits_name: "Lightbits-NVMe-TCP"
-
-cinder_ceph_backends:
-  - name: "{{ cinder_backend_ceph_name }}"
-    backend_name: "{{ cinder_backend_ceph_name }}"
-    cluster: "{{ ceph_cluster }}"
-    user: "{{ ceph_cinder_user }}"
-    pool: "{{ ceph_cinder_pool_name }}"
-    enabled: "{{ cinder_backend_ceph | bool }}"
-
-cinder_backup_backend_ceph_name: "rbd-1"
-cinder_backup_ceph_backend: >-
-  {{
-    cinder_ceph_backends |
-    selectattr('name', 'equalto', cinder_backup_backend_ceph_name) | list | first |
-    combine({'pool': ceph_cinder_backup_pool_name, 'user': ceph_cinder_backup_user})
-  }}
-
+# NOTE: the cinder backend definitions (cinder_backends, cinder_ceph_backends,
+# cinder_enabled_backends, cinder_backup_backend_ceph_name,
+# cinder_backup_ceph_backend and the cinder_backend_*_name variables) are
+# defined in group_vars/all/cinder.yml so that all cinder backend definitions
+# live in one place and are in scope for the iscsi role.
 skip_cinder_backend_check: false
 
-cinder_enabled_backends: >-
-  {{
-    cinder_backends | selectattr('enabled', 'equalto', true) | list
-    + cinder_ceph_backends | selectattr('enabled', 'equalto', true) | list
-  }}
-
 ####################
 # Notification
 ####################
diff --git a/releasenotes/notes/fix-iscsi-cinder-enabled-backends-f482e5454dc8fa87.yaml b/releasenotes/notes/fix-iscsi-cinder-enabled-backends-f482e5454dc8fa87.yaml
new file mode 100644
index 000000000..3945ee4da
--- /dev/null
+++ b/releasenotes/notes/fix-iscsi-cinder-enabled-backends-f482e5454dc8fa87.yaml
@@ -0,0 +1,10 @@
+---
+fixes:
+  - |
+    Fixes ``kolla-ansible prechecks`` (and deploy/reconfigure) failing with
+    ``'cinder_enabled_backends' is undefined`` in the ``iscsi`` role when a
+    Cinder iSCSI/LVM backend is enabled. The ``cinder_enabled_backends`` and
+    related backend variables are now defined in ``group_vars/all`` so that
+    they are in scope for the ``iscsi`` role, whose play runs before the
+    ``cinder`` play. `LP#2158120
+    <https://bugs.launchpad.net/kolla-ansible/+bug/2158120>`__