feat(pgsql): update pg-backup strategy before update hugepage

- full backup when ansible_play_hosts_all contains primary
- full or incremental backup when ansible_play_hosts_all contains no primary

tested scenarios:
- `./pgsql.yml -l <pg_cls> -t pg_hugepage`
  - full backup
- `./pgsql.yml -l '<replica>,<primary>,&<pg_cls>' -t pg_hugepage`
  - full backup
- `./pgsql.yml -l '<replica>,&<pg_cls>' -t pg_hugepage`
  - full or incremental backup

Author: waitingsong

roles/pgsql/tasks/pg_hugepage.yml

@@ -59,9 +59,10 @@
            pt_restart: {{ pt_restart|bool }}
       changed_when: false
 
-    - name: full backup pg before hugepage update if has primary
+    # full back if contains primary, otherwise backup (full or incremental) at primary
+    - name: pg-backup before update hugepage
       include_tasks: util/pg_backup.yml
-      when: hugepages_need_update|bool and pg_role == 'primary'
+      when: hugepages_need_update|bool
 
     - name: update hugepage
       include_tasks: util/pg_write_hugepage.yml

roles/pgsql/tasks/util/pg_backup.yml

@@ -1,9 +1,22 @@
 #!/usr/bin/ansible-playbook
 ---
+#--------------------------------------------------------------#
+# backup pg_cls if pgbackrest enabled               [pg_backup]
+# - full backup when ansible_play_hosts_all contains primary
+# - full or incremental backup when ansible_play_hosts_all contains no primary
+#--------------------------------------------------------------#
+# tested scenarios:
+# - `./pgsql.yml -l <pg_cls> -t pg_hugepage`
+#   - full backup
+# - `./pgsql.yml -l '<replica>,<primary>,&<pg_cls>' -t pg_hugepage`
+#   - full backup
+# - `./pgsql.yml -l '<replica>,&<pg_cls>' -t pg_hugepage`
+#   - full or incremental backup
+#--------------------------------------------------------------#
 
 - name: set variable
   tags: [ pg_hugepage, patroni, pg_launch, pt_restart ]
-  when: pg_role_runtime is undefined
+  when: pg_role_runtime is undefined or pg_primary_host_runtime is undefined
   block:
     - name: run pg-role
       command: /pg/bin/pg-role
@@ -13,29 +26,49 @@
       set_fact:
         pg_role_runtime: "{{ pg_role_cmd.stdout | default(pg_role) | trim }}"
 
+    - name: set variable pg_role_runtime
+      set_fact:
+        pg_role_runtime: "{{ pg_role_cmd.stdout | default(pg_role) | trim }}"
+
+    - name: set pg_primary_host_runtime
+      tags: [ pg_hugepage, patroni, pg_launch, pt_restart ]
+      import_tasks: util/patroni_primary_runtime.yml
 
 - name: pg_backup
   tags: [ pg_hugepage, patroni, pg_launch, pt_restart ]
   when: pgbackrest_enabled|bool
+  become_user: "{{ pg_dbsu }}"
   vars:
-    dbsu: "{{ pg_dbsu|default('postgres') }}"
     pg_role: "{{ pg_role_runtime }}"
   block:
     - name: full backup cls {{ pg_cluster }}
-      become_user: "{{ dbsu }}"
       when: pg_role == 'primary'
       command: /pg/bin/pg-backup full
       register: back_ret_cmd
       ignore_errors: false
 
     - name: show backup result for {{ pg_cluster }}
-      when: pg_role == 'primary'
+      when: pg_role == 'primary' and back_ret_cmd is defined
       debug:
         msg: |
           STDOUT {{ back_ret_cmd.stdout_lines }},
            STDERR {{ back_ret_cmd.stderr_lines }}
       changed_when: false
 
+    - name: set variable pt_backup_at_primary from primary
+      when: pg_role != 'primary' and pg_role_runtime is defined
+      set_fact:
+        pt_backup_at_primary: "{{ (hostvars[pg_primary_host_runtime].back_ret_cmd | default(false) | string | trim | bool) }}"
+      changed_when: false
+
+    - name: full or incr backup cls {{ pg_cluster }} if contains no primary at primary
+      when: pg_role != 'primary' and (not pt_backup_at_primary) and pg_role_runtime is defined
+      command: /pg/bin/pg-backup
+      register: back_ret_cmd
+      delegate_to: "{{ pg_primary_host_runtime }}"
+      run_once: true
+
+
   rescue:
     - name: pg-backup failed for {{ pg_cluster }}
       debug: