feat(pg_wal): add parameter pg_fs_wal (G) for define/changing pg_wal dir

new pg_wal style is `<pg_fs_wal>/<pg_cluster>-<pg_version>/pg_wal` when pg_fs_wal defined

pg_fs_wal validatiton: pg_fs_wal must start with '/' and not contain spaces

modify pg_wal of current pg_cluster:
1. edit and save pigsty.yml by setting the global `pg_wal`
2. run command `./pgsql.yml -l <cls> -t pg_wal`

tested scenarios:
- `pig sty install`
  - pg_fs_wal undefined
  - pg_fs_wal defined
- `bin/pgsql-add pg-a`
  - pg_fs_wal undefined
  - pg_fs_wal defined
- `./pgsql.yml -t pg_wal`
  - set pg_fs_wal=/wal
  - set pg_fs_wal=/wal2 (from /wal)
  - remove pg_fs_wal (from /wal2)
- multiple call `./pgsql.yml -t pg_wal`
  - keep pg_fs_wal undefined or blank
  - keep pg_fs_wal=/wal

`pg-backup full` will be executed automatically if pg_fs_wal changed and apply this settings:
- full installation with valid pg_fs_wal (no backup operation if pg_fs_wal undefined or blank)
- pg_fs_wal changed after installation
  - undefined or empty to `/wal`
  - `/wal` to `/wal2`
  - `/wal2` to undefined or empty

Author: waitingsong

roles/pg_remove/tasks/main.yml

@@ -90,6 +90,13 @@
     - /pg/data
     - "{{ pg_fs_main }}/postgres"
 
+- name: remove pg_fs_wal/?/pg_wal (if pg_fs_wal defined)
+  tags: pg_data
+  when: pg_clean|bool and (pg_fs_wal | length > 0)
+  ignore_errors: yes
+  file: path={{ item }} state=absent
+  with_items:
+    - "{{ pg_fs_wal }}/{{ pg_cluster }}-{{ pg_version }}"
 
 #--------------------------------------------------------------#
 # remove packages                                       [pg_pkg]
@@ -120,12 +127,12 @@
         pg_packages_list: |-
           {% set pkg_map = package_map | default({}) %}
           {% for pkg_list in pg_packages %}{% for pkg in pkg_list | trim | regex_replace('(,|\\s)+', ',') | regex_findall('([^,\\s]+)') | default([]) %}{% if pkg != '' %}{% if pkg in pkg_map %}{% set pkg = pkg_map[pkg] %}{% endif %}{% if not loop.first %},{% endif %}{{ pkg|replace('${pg_version}', pg_version|string)|replace('$v', pg_version|string) }}{% endif %}{% endfor %}
-          
+
           {% endfor %}
         pg_extension_list: |-
           {% set pkg_map = package_map | default({}) %}
           {% for ext_list in pg_extensions %}{% for ext in ext_list | trim | regex_replace('(,|\\s)+', ',') | regex_findall('([^,\\s]+)') | default([]) %}{% if ext != '' %}{% if ext in pkg_map %}{% set ext = pkg_map[ext] %}{% endif %}{% if not loop.first %},{% endif %}{{ ext|replace('${pg_version}', pg_version|string)|replace('$v', pg_version|string) }}{% endif %}{% endfor %}
-          
+
           {% endfor %}
 
     # uninstall extensions first

roles/pgsql/defaults/main.yml

@@ -56,6 +56,7 @@ pg_safeguard: false               # prevent purging running postgres instance? f
 pg_clean: true                    # purging existing postgres during pgsql init? true by default
 pg_data: /pg/data                 # postgres data directory, `/pg/data` by default
 pg_fs_main: /data                 # mountpoint/path for postgres main data, `/data` by default
+pg_fs_wal: ''                     # mountpoint/path for pg_wal dir, default blank, new pg_wal will be <pg_fs_wal>/<pg_cluster>-<pg_version>/pg_wal
 pg_fs_bkup: /data/backups         # mountpoint/path for pg backup data, `/data/backup` by default
 pg_storage_type: SSD              # storage type for pg main data, SSD,HDD, SSD by default
 pg_dummy_filesize: 64MiB          # size of `/pg/dummy`, hold 64MB disk space for emergency use

roles/pgsql/tasks/clean.yml

@@ -19,7 +19,7 @@
       ignore_errors: false
       fail:
         msg: >-
-          Abort because the node {{ inventory_hostname }} seems not managed by pigsty, use ./node.yml to init node first.  
+          Abort because the node {{ inventory_hostname }} seems not managed by pigsty, use ./node.yml to init node first.
 
     # check postgres by listening port
     - name: check postgres exists
@@ -41,7 +41,7 @@
       ignore_errors: false
       fail:
         msg: >-
-          Abort because pg instance {{ pg_cluster }}-{{ pg_seq }} @ {{ inventory_hostname }} exists. 
+          Abort because pg instance {{ pg_cluster }}-{{ pg_seq }} @ {{ inventory_hostname }} exists.
            {% if pg_safeguard|bool %}pg_safeguard enabled, please disable it before purging.{% endif %}
            {% if not pg_clean|bool %}pg_clean = false, use -e pg_safeguard=false to override.{% endif %}
 
@@ -94,7 +94,7 @@
         rm -rf /lib/systemd/system/[email protected] /lib/systemd/system/postgresql.service /etc/init.d/postgresql
         systemctl daemon-reload
         {% endif %}
-        
+
         if ps -u postgres -o pid:1,command | grep -E 'postmaster|postgres:|-D' ; then
             {{ pg_bin_dir }}/pg_ctl -D {{ pg_data }} stop --mode=immediate
         fi
@@ -121,7 +121,7 @@
         {% else %}
         META_DIR="{{ pg_namespace|default('/pg') }}/{{ pg_cluster }}"
         {% endif %}
-        
+
         export ETCDCTL_API=3
         export ETCDCTL_ENDPOINTS="{% for ip in groups['etcd']|sort %}{% if not loop.first %},{% endif %}https://{{ ip }}:{{ etcd_port }}{% endfor %}"
         export ETCDCTL_CACERT=/etc/pki/ca.crt
@@ -145,4 +145,10 @@
         - /etc/pgbouncer
         - /var/run/pgbouncer
 
+    - name: remove pg_fs_wal/?/pg_wal (if pg_fs_wal defined)
+      tags: pg_clean_data
+      when: pg_fs_wal | length > 0
+      file: path={{ item }} state=absent
+      with_items:
+        - "{{ pg_fs_wal }}/{{ pg_cluster }}-{{ pg_version }}"
 ...

roles/pgsql/tasks/dir.yml

@@ -42,6 +42,10 @@
         - "{{ pg_backup_dir }}/backup"
         - "/var/run/postgresql"
 
+    - name: List files in a directory
+      ansible.builtin.command:
+        cmd: ls "{{ pg_cluster_dir }}/data"
+
     # make sure the /var/run/postgresql is created
     - name: create /var/run/postgresql tmpfiles.d
       copy:

roles/pgsql/tasks/main.yml

@@ -83,6 +83,12 @@
   tags: pgbackrest
   when: pgbackrest_enabled|bool
 
+#--------------------------------------------------------------#
+# WAL                                                   [pg_wal]
+#--------------------------------------------------------------#
+- import_tasks: pg_wal.yml
+  tags: pg_wal
+
 #--------------------------------------------------------------#
 # Pgbouncer                                          [pgbouncer]
 #--------------------------------------------------------------#

roles/pgsql/tasks/pg_wal.yml

@@ -0,0 +1,100 @@
+#!/usr/bin/ansible-playbook
+---
+#--------------------------------------------------------------#
+# Modify pg_wal destination if pg_fs_wal defined        [pg_wal]
+# new pg_wal is <pg_fs_wal>/<pg_cluster>-<pg_version>/pg_wal
+#--------------------------------------------------------------#
+
+- name: run pg-role
+  command: /pg/bin/pg-role
+  register: pg_role_cmd
+
+- name: update variable pg_role
+  set_fact:
+    pg_role: "{{ pg_role_cmd.stdout | trim }}"
+
+- name: validate variable pg_fs_wal
+  tags: [ validate_pg_fs_wal ]
+  when: pg_fs_wal | length > 0
+  block:
+    - name: validate pg_fs_wal "{{ pg_fs_wal }}"
+      fail:
+        msg: "The variable pg_fs_wal  must start with '/' and not contain spaces"
+      when: >
+        (pg_fs_wal[0] != '/') or (' ' in pg_fs_wal)
+
+- name: retrieve path of pg_wal directory
+  become: yes
+  block:
+    - name: validate variable pg_data
+      assert:
+        that: pg_data is defined and pg_data | length > 0
+        msg: "pg_data must be defined"
+      changed_when: false
+
+    - name: get current pg_wal real path
+      command: realpath -m "{{ pg_data }}/pg_wal"
+      register: real_curr_pg_wal_cmd
+      changed_when: false
+
+    - name: calculate new pg_data path (parent of target pg_wal)
+      set_fact:
+        target_new_pg_data: >-
+          {% if pg_fs_wal is defined and pg_fs_wal %}
+          {{ pg_fs_wal | trim }}/{{ pg_cluster }}-{{ pg_version }}
+          {% else %}
+          {{ pg_data }}
+          {% endif %}
+      changed_when: false
+
+    - name: get target pg_wal real path
+      command: "realpath -m {{ target_new_pg_data }}"    # do not quote the var like "{{ target_new_pg_data }}"
+      register: new_pg_data_cmd
+      changed_when: false
+
+    - name: Set final path facts
+      set_fact:
+        new_pg_data: "{{ new_pg_data_cmd.stdout }}"
+        real_curr_pg_wal: "{{ real_curr_pg_wal_cmd.stdout }}"
+        pg_wal_dst: "{{ new_pg_data_cmd.stdout }}/pg_wal"
+      changed_when: false
+
+    - name: get current pg_wal stat
+      stat:
+        path: "{{ pg_data }}/pg_wal"  # do not use real_curr_pg_wal, use pg_data instead
+      register: real_curr_pg_wal_stat
+      changed_when: false
+
+    - name: Set real_curr_pg_wal_is_link variable
+      set_fact:
+        real_curr_pg_wal_is_link: "{{ real_curr_pg_wal_stat.stat.exists and real_curr_pg_wal_stat.stat.islnk }}"
+      changed_when: false
+
+    - name: variable output for pg_wal
+      debug:
+        msg: |
+          real_curr_pg_wal: {{ real_curr_pg_wal }}, pg_wal_dst: {{ pg_wal_dst }},
+           real_curr_pg_wal_is_link: {{ real_curr_pg_wal_is_link }},
+           pg_data: {{ pg_data }}, new_pg_data: {{ new_pg_data }},
+           pg_fs_wal: {{ pg_fs_wal }},
+      changed_when: false
+
+
+
+#--------------------------------------------------------------#
+# Modify WAL                                     [modify_pg_wal]
+#--------------------------------------------------------------#
+- include_tasks: pg_wal/pg_wal_modification.yml
+  tags: modify_pg_wal
+  when: (real_curr_pg_wal != pg_wal_dst) and (pg_fs_wal | length > 0)
+
+
+#--------------------------------------------------------------#
+# Restore WAL                                   [restore_pg_wal]
+#--------------------------------------------------------------#
+- include_tasks: pg_wal/pg_wal_restoration.yml
+  tags: restore_pg_wal
+  when: (real_curr_pg_wal != pg_wal_dst) and (pg_fs_wal is not defined or (pg_fs_wal | trim | length == 0))
+
+
+...

roles/pgsql/tasks/pg_wal/pg_wal_after.yml

@@ -0,0 +1,30 @@
+#!/usr/bin/ansible-playbook
+---
+
+- name: operations after updating pg_wal dir
+  vars:
+    tmp_wal_dir:    "pg_wal.tmp-backup"
+    pg_data_lock:   "{{ pg_data }}.locked"
+    pg_wal_src_tmp: "{{ pg_data_lock }}/{{ tmp_wal_dir }}"
+  block:
+    - import_tasks: ../util/grace_start_pg.yml
+    - import_tasks: ../util/grace_patroni_resume.yml
+
+    # finally, check if all postgres is ready
+    - import_tasks: ../util/check_pg_ready.yml
+
+    - name: clean tmp directory after modifying pg_wal
+      ignore_errors: yes
+      file: path={{ item }} state=absent
+      with_items:
+        - "{{ pg_data }}/{{ tmp_wal_dir }}"
+        - "{{ pg_wal_src_tmp }}"
+
+    - name: clean old pg_wal directory after modifying pg_wal
+      ignore_errors: yes
+      when: (real_curr_pg_wal != pg_wal_dst) and (real_curr_pg_wal_is_link == true)
+      file: path={{ item }} state=absent
+      with_items:
+        - "{{ real_curr_pg_wal }}"
+
+...

roles/pgsql/tasks/pg_wal/pg_wal_before.yml

@@ -0,0 +1,21 @@
+#!/usr/bin/ansible-playbook
+---
+
+- name: operations before updating pg_wal dir
+  vars:
+    tmp_wal_dir:    "pg_wal.tmp-backup"
+    pg_data_lock:   "{{ pg_data }}.locked"
+    pg_wal_src_tmp: "{{ pg_data_lock }}/{{ tmp_wal_dir }}"
+  any_errors_fatal: true
+  block:
+    - import_tasks: ../util/pg_backup.yml
+    - import_tasks: ../util/grace_patroni_pause.yml
+    - import_tasks: ../util/grace_stop_pg.yml
+
+    - name: clean tmp dir before modify pg_wal
+      file: path={{ item }} state=absent
+      with_items:
+        - "{{ pg_data_lock }}"
+        - "{{ pg_wal_src_tmp }}"
+
+...

roles/pgsql/tasks/pg_wal/pg_wal_modification.yml

@@ -0,0 +1,67 @@
+#!/usr/bin/ansible-playbook
+---
+#--------------------------------------------------------------#
+# Modify pg_wal destination if pg_fs_wal defined        [pg_wal]
+# new pg_wal is <pg_fs_wal>/<pg_cluster>-<pg_version>/pg_wal
+#--------------------------------------------------------------#
+
+- name: modify postgres wal directory to pg_fs_wal
+  vars:
+    tmp_wal_dir:    "pg_wal.tmp-backup"
+    pg_data_lock:    "{{ pg_data }}.locked"
+    pg_wal_src:     "{{ pg_data_lock }}/pg_wal"
+    pg_wal_src_tmp: "{{ pg_data_lock }}/{{ tmp_wal_dir }}"
+    dbsu:           "{{ pg_dbsu|default('postgres') }}"
+  when: (pg_fs_wal | length > 0) and (real_curr_pg_wal != pg_wal_dst)
+  block:
+    - name: stat new pg_wal before modifying pg_wal
+      find:
+        paths: "{{ pg_wal_dst }}"
+      register: pg_wal_dst_stat
+      ignore_errors: yes
+
+    - name: check if new pg_wal is empty
+      fail:
+        msg: "The directory is not empty: {{ pg_wal_dst }} "
+      when: pg_wal_dst_stat.matched > 0
+
+    - name: create new pg_data dir before modifying pg_wal
+      file: path={{ item }} state=directory owner={{ dbsu }} group=postgres mode=0700
+      with_items:
+        - "{{ new_pg_data }}"
+
+    - import_tasks: pg_wal_before.yml
+
+    - name: clean tmp dir before modify pg_wal
+      file: path={{ item }} state=absent
+      with_items:
+        - "{{ pg_wal_dst }}"
+
+    - name: lock pg data directory temporarily before modifying pg_wal
+      command: mv "{{ pg_data }}" "{{ pg_data_lock }}"
+
+    - name: copy files from backup pg_wal to {{ new_pg_data }}
+      copy:
+        src: "{{ pg_wal_src }}"
+        dest: "{{ new_pg_data }}"
+        owner: postgres
+        group: postgres
+        mode: '0700'
+        remote_src: yes
+
+    - name: backup current pg_wal
+      command: mv "{{ pg_wal_src }}" "{{ pg_wal_src_tmp }}"
+
+    - name: create symlink for pg_wal
+      file:
+        src: "{{ pg_wal_dst }}"
+        dest: "{{ pg_wal_src }}"
+        state: link
+        force: yes
+
+    - name: restore pg data directory after modifying pg_wal
+      command: mv "{{ pg_data_lock }}" "{{ pg_data }}"
+
+    - import_tasks: pg_wal_after.yml
+
+...

roles/pgsql/tasks/pg_wal/pg_wal_restoration.yml

@@ -0,0 +1,58 @@
+#!/usr/bin/ansible-playbook
+---
+#--------------------------------------------------------------#
+# Modify pg_wal destination if pg_fs_wal defined        [pg_wal]
+# new pg_wal is <pg_fs_wal>/<pg_cluster>-<pg_version>/pg_wal
+#--------------------------------------------------------------#
+
+- name: restore postgres wal directory to default
+  vars:
+    tmp_wal_dir:    "pg_wal.tmp-backup"
+    pg_data_lock:   "{{ pg_data }}.locked"
+    pg_wal_src:     "{{ pg_data_lock }}/pg_wal"
+    pg_wal_src_tmp: "{{ pg_data_lock }}/{{ tmp_wal_dir }}"
+    dbsu:           "{{ pg_dbsu|default('postgres') }}"
+  when: real_curr_pg_wal_is_link == true
+  block:
+    - import_tasks: pg_wal_before.yml
+
+    - name: lock pg data directory temporarily before restoring pg_wal
+      command: mv "{{ pg_data }}" "{{ pg_data_lock }}"
+
+    - name: copy current pg_wal to {{ pg_wal_src_tmp }}
+      become: yes
+      copy:
+        src: "{{ pg_wal_src }}"
+        dest: "{{ pg_wal_src_tmp }}"
+        owner: "{{ dbsu }}"
+        group: "{{ dbsu }}"
+        mode: '0700'
+        remote_src: yes
+
+    - name: unlink current pg_wal
+      file: path={{ item }} state=absent
+      with_items:
+        - "{{ pg_wal_src }}"
+
+    - name: restore default pg_wal
+      become: yes
+      command: mv "{{ pg_wal_src_tmp }}/pg_wal" "{{ pg_wal_src }}"
+
+    - name: update pg_wal owner
+      args: { executable: /bin/bash }
+      shell: |
+        chown -R {{ dbsu }}:{{ dbsu }} "{{ pg_wal_src }}"
+        chmod -R 0700 "{{ pg_wal_src }}"
+
+    - name: remove tmp directory after restoring pg_wal
+      become: yes
+      file: path={{ item }} state=absent
+      with_items:
+        - "{{ pg_wal_src_tmp }}"
+        - "{{ real_curr_pg_wal }}"
+
+    - name: restore pg data directory after restoring pg_wal
+      command: mv "{{ pg_data_lock }}" "{{ pg_data }}"
+
+    - import_tasks: pg_wal_after.yml
+...