F OpenNebula/one-deploy#140: Eliminate ID prediction in generic DS mode

playbooks/site.yml

@@ -1,6 +1,6 @@
 ---
 - hosts: all
-  tags: [frontend, node, grafana, stage1, stage2, stage3]
+  tags: [frontend, node, grafana, stage1, stage2, stage3, stage4]
   collections:
     - opennebula.deploy
   roles:
@@ -101,6 +101,17 @@
       tags: [prometheus]
       when: *prometheus
 
+- hosts: "{{ node_group | d('node') }}"
+  tags: [node, stage2]
+  collections:
+    - opennebula.deploy
+  roles:
+    # NOTE: If datastore IDs are not "predicted" for the generic mode, we try to post-patch
+    #       symlinks iff IDs are merged back into the ds_dict (otherwise nothing should happen).
+    - role: datastore/node
+      tags: [datastore]
+      when: ds.mode is defined and ds.mode == 'generic'
+
 - hosts: "{{ grafana_group | d('grafana') }}"
   collections:
     - opennebula.deploy

roles/datastore/generic/tasks/_init.yml

@@ -0,0 +1,24 @@
+---
+- name: Compute helper facts
+  ansible.builtin.set_fact:
+    ds_names: >-
+      {{ hostvars[leader | d(omit)].ds_names | d(_items | map(attribute='key') | list) }}
+    ds_dict: >-
+      {{ hostvars[leader | d(omit)].ds_dict | d(_items | items2dict) }}
+  vars:
+    _ds: >-
+      {{ ds_defaults | combine(ds.config | d({}), recursive=true) }}
+    _items: >-
+      {{ _ds | dict2items
+             | map(attribute='value')
+             | map('dict2items')
+             | flatten
+             | rejectattr('value.managed', 'false') }}
+
+- name: Ensure /var/lib/one/datastores/ exists
+  ansible.builtin.file:
+    path: /var/lib/one/datastores/
+    state: directory
+    owner: 9869 # oneadmin
+    group: 9869 # oneadmin
+    mode: u=rwx,g=rx,o=

roles/datastore/generic/tasks/_link.yml

@@ -0,0 +1,48 @@
+---
+- name: Convert datastore directories into symlinks
+  ansible.builtin.shell:
+    cmd: |
+      set -o errexit
+
+      if [[ -L '{{ _base_path }}' ]]; then
+        exit 0
+      fi
+
+      if ! [[ -d '{{ _mount_path }}' ]]; then
+        echo 'Symlink target {{ _mount_path }} does not exist or is not a directory.' >&2
+        exit 1
+      fi
+
+      if [[ -d '{{ _base_path }}' ]] && ! rmdir '{{ _base_path }}'; then
+        exit 2
+      fi
+
+      if ! ln -s '{{ _mount_path }}' '{{ _base_path }}'; then
+        exit 3
+      fi
+
+      exit 78 # EREMCHG
+    executable: /bin/bash
+  when:
+    - inventory_hostname in _hosts
+    - ds_dict[item].id is defined
+    # NOTE: It doesn't really make sense to symlink /var/lib/one/datastores/,
+    #       so we use that as a skip condition.
+    - _mount_path != '/var/lib/one/datastores'
+  vars:
+    # This isn't strictly a "mountpoint".
+    _mount_path: >-
+      {{ ds_dict[item].symlink.src | d('/var/lib/one/datastores/') | normpath }}
+    _base_path: >-
+      /var/lib/one/datastores/{{ ds_dict[item].id }}
+    _hosts: >-
+      {{ ds_dict[item].symlink.groups | d([])
+                                      | map('extract', groups)
+                                      | flatten
+                                      | unique }}
+  register: shell
+  changed_when:
+    - shell.rc in [78]
+  failed_when:
+    - shell.rc not in [0, 78]
+  loop: "{{ ds_names }}"

roles/datastore/generic/tasks/frontend.yml

@@ -1,12 +1,13 @@
 ---
 - ansible.builtin.import_tasks:
-    file: "{{ role_path }}/tasks/common.yml"
+    file: "{{ role_path }}/tasks/_init.yml"
 
 - ansible.builtin.include_role:
     name: opennebula/leader
   when: leader is undefined
 
-- when: inventory_hostname == leader
+- delegate_to: "{{ leader }}"
+  run_once: true
   block:
     - name: Get Datastores
       ansible.builtin.shell:
@@ -15,22 +16,20 @@
       changed_when: false
       register: shell
 
-- name: Parse Datastores
-  ansible.builtin.set_fact:
-    ds_names_parsed: >-
-      {{ _names }}
-    ds_dict_parsed: >-
-      {{ dict(_names | zip(_datastores)) }}
-  vars:
-    _document: >-
-      {{ shell.stdout | from_json }}
-    _datastores: >-
-      {{ [_document.DATASTORE_POOL.DATASTORE | d([])] | flatten }}
-    _names: >-
-      {{ _datastores | map(attribute='NAME') | d([]) | list }}
+    - name: Parse Datastores
+      ansible.builtin.set_fact:
+        ds_names_parsed: >-
+          {{ _names }}
+        ds_dict_parsed: >-
+          {{ dict(_names | zip(_datastores)) }}
+      vars:
+        _document: >-
+          {{ shell.stdout | from_json }}
+        _datastores: >-
+          {{ [_document.DATASTORE_POOL.DATASTORE | d([])] | flatten }}
+        _names: >-
+          {{ _datastores | map(attribute='NAME') | d([]) | list }}
 
-- when: inventory_hostname == leader
-  block:
     # NOTE: Only "system" datastores can be enabled or disabled.
     - name: Update Datastores
       ansible.builtin.shell:
@@ -49,9 +48,11 @@
           {{ _combined | opennebula.deploy.to_one }}
         executable: /bin/bash
       changed_when: true
-      when: (_combined | opennebula.deploy.to_one != ds_dict_parsed[item].TEMPLATE | opennebula.deploy.to_one)
-            or
-            (ds_dict[item].enabled is defined and (ds_dict[item].enabled != (ds_dict_parsed[item].STATE | int == 0)))
+      when:
+        - ds_dict[item].id is defined
+        - (_combined | opennebula.deploy.to_one != ds_dict_parsed[item].TEMPLATE | opennebula.deploy.to_one)
+          or
+          (ds_dict[item].enabled is defined and (ds_dict[item].enabled != (ds_dict_parsed[item].STATE | int == 0)))
       loop: "{{ _existing }}"
       vars:
         _existing: >-
@@ -73,6 +74,29 @@
         executable: /bin/bash
       changed_when: true
       loop: "{{ _missing }}"
+      register: shell_create_datastores
       vars:
         _missing: >-
           {{ ds_names | reject('in', ds_names_parsed) }}
+
+    - name: Merge back datastore IDs into ds_dict
+      ansible.builtin.set_fact:
+        ds_dict: >-
+          {{ ds_dict | combine(_update1, _update2, recursive=true) }}
+      vars:
+        # IDs can be sourced either from initial parse or immediately after new datastores are created.
+        _update1: >-
+          {%- set output = [] -%}
+          {%- for item in ds_dict_parsed.items() -%}
+          {{- output.append([item.0, {"id": item.1.ID | int}]) -}}
+          {%- endfor -%}
+          {{- dict(output) -}}
+        _update2: >-
+          {%- set output = [] -%}
+          {%- for item in shell_create_datastores.results -%}
+          {{- output.append([item.item, {"id": item.stdout_lines[-1].split(':')[-1] | trim | int}]) -}}
+          {%- endfor -%}
+          {{- dict(output) -}}
+
+- ansible.builtin.import_tasks:
+    file: "{{ role_path }}/tasks/_link.yml"

roles/datastore/generic/tasks/node.yml

@@ -1,3 +1,6 @@
 ---
 - ansible.builtin.import_tasks:
-    file: "{{ role_path }}/tasks/common.yml"
+    file: "{{ role_path }}/tasks/_init.yml"
+
+- ansible.builtin.import_tasks:
+    file: "{{ role_path }}/tasks/_link.yml"