upgrade: compatibility with multiple pgbouncers

molecule/pg_upgrade/converge.yml

@@ -16,6 +16,7 @@
         consul_node_role: server # if dcs_type: "consul"
         consul_bootstrap_expect: true # if dcs_type: "consul"
         postgresql_version: "14" # redefine the version to install for the upgrade test
+        pgbouncer_processes: 1 # Test multiple pgbouncer processes (so_reuseport)
         cacheable: true
 
     - name: Set variables for custom PostgreSQL data and WAL directory test

roles/pgbouncer/templates/pgbouncer.ini.j2

@@ -7,10 +7,10 @@
 
 [pgbouncer]
 logfile = {{ pgbouncer_log_dir }}/pgbouncer{{ '-%d' % (idx + 1) if idx > 0 else '' }}.log
-pidfile = /run/pgbouncer/pgbouncer{{ '-%d' % (idx + 1) if idx > 0 else '' }}.pid
+pidfile = /run/pgbouncer{{ '-%d' % (idx + 1) if idx > 0 else '' }}/pgbouncer.pid
 listen_addr = {{ pgbouncer_listen_addr | default('0.0.0.0') }}
 listen_port = {{ pgbouncer_listen_port | default(6432) }}
-unix_socket_dir = /run/pgbouncer/pgbouncer{{ '-%d' % (idx + 1) if idx > 0 else '' }}
+unix_socket_dir = /var/run/pgbouncer{{ '-%d' % (idx + 1) if idx > 0 else '' }}
 auth_type = {{ pgbouncer_auth_type }}
 {% if pgbouncer_auth_user | bool %}
 auth_user = {{ pgbouncer_auth_username }}

roles/pgbouncer/templates/pgbouncer.service.j2

@@ -9,16 +9,16 @@ User=postgres
 Group=postgres
 
 PermissionsStartOnly=true
-ExecStartPre=-/bin/mkdir -p /run/pgbouncer/pgbouncer{{ '-%d' % (idx + 1) if idx > 0 else '' }} {{ pgbouncer_log_dir }}
-ExecStartPre=/bin/chown -R postgres:postgres /run/pgbouncer {{ pgbouncer_log_dir }}
+ExecStartPre=-/bin/mkdir -p /run/pgbouncer /var/run/pgbouncer{{ '-%d' % (idx + 1) if idx > 0 else '' }} {{ pgbouncer_log_dir }}
+ExecStartPre=/bin/chown -R postgres:postgres /run/pgbouncer /var/run/pgbouncer{{ '-%d' % (idx + 1) if idx > 0 else '' }} {{ pgbouncer_log_dir }}
 {% if ansible_os_family == "Debian" %}
 ExecStart=/usr/sbin/pgbouncer -d {{ pgbouncer_conf_dir }}/pgbouncer{{ '-%d' % (idx + 1) if idx > 0 else '' }}.ini
 {% endif %}
 {% if ansible_os_family == "RedHat" %}
 ExecStart=/usr/bin/pgbouncer -d {{ pgbouncer_conf_dir }}/pgbouncer{{ '-%d' % (idx + 1) if idx > 0 else '' }}.ini
 {% endif %}
 ExecReload=/bin/kill -SIGHUP $MAINPID
-PIDFile=/run/pgbouncer/pgbouncer{{ '-%d' % (idx + 1) if idx > 0 else '' }}.pid
+PIDFile=/run/pgbouncer{{ '-%d' % (idx + 1) if idx > 0 else '' }}/pgbouncer.pid
 Restart=on-failure
 
 LimitNOFILE=100000

roles/upgrade/tasks/pgbouncer_pause.yml

@@ -36,6 +36,21 @@
       and state <> 'idle'
       and query_start < clock_timestamp() - interval '{{ pg_slow_active_query_treshold_to_terminate }} ms'
       {{ "and backend_type = 'client backend'" if pg_old_version is version('10', '>=') else '' }}
+    # Depending on the number of PgBouncer processes, it either uses a local connection or the socket paths for each PgBouncer process.
+    pgbouncer_pause_command: >-
+      {% if pgbouncer_processes | default(1) | int == 1 %}
+      bash -c 'PGPASSWORD={{ patroni_superuser_password }} psql -h localhost -p {{ pgbouncer_listen_port }} -U {{ patroni_superuser_username }} -d pgbouncer -tAXc "PAUSE"'
+      {% else %}
+        {% set unix_socket_dir = [] %}
+        {% for i in range(0, pgbouncer_processes | default(1) | int) %}
+            {% if i == 0 %}
+                {{ unix_socket_dir.append('/var/run/pgbouncer') }}
+            {% else %}
+                {{ unix_socket_dir.append('/var/run/pgbouncer-' + i | string) }}
+            {% endif %}
+        {% endfor %}
+        echo -e "{{ unix_socket_dir | join('\n') }}" | xargs -I {} -P {{ pgbouncer_processes | default(1) | int }} bash -c 'PGPASSWORD={{ patroni_superuser_password }} psql -h {} -p {{ pgbouncer_listen_port }} -U {{ patroni_superuser_username }} -d pgbouncer -tAXc "PAUSE"'
+      {% endif %}
   ansible.builtin.shell: |
     set -o pipefail;
 
@@ -46,7 +61,7 @@
     # it is assumed that pgbouncer is installed on database servers
     pgb_servers="$pg_servers"
     pgb_count="$pg_count"
-    pgb_pause_command="psql -h localhost -p {{ pgbouncer_listen_port }} -U {{ patroni_superuser_username }} -d pgbouncer -tAXc \"PAUSE\""
+    pgb_pause_command="{{ pgbouncer_pause_command }}"
     pgb_resume_command='kill -SIGUSR2 $(pidof pgbouncer)'
 
     start_time=$(date +%s)

roles/upgrade/tasks/pre_checks.yml

@@ -336,12 +336,38 @@
 # PgBouncer (if 'pgbouncer_pool_pause' is 'true')
 # test access via localhost to be able to perform 'PAUSE' command
 - name: '[Pre-Check] Test PgBouncer access via localhost'
-  ansible.builtin.command: >
-    psql -h localhost -p {{ pgbouncer_listen_port }} -U {{ patroni_superuser_username }} -d pgbouncer -tAXc "SHOW POOLS"
+  ansible.builtin.command: >-
+    psql -h localhost
+    -p {{ pgbouncer_listen_port }}
+    -U {{ patroni_superuser_username }}
+    -d pgbouncer
+    -tAXc "SHOW POOLS"
+  changed_when: false
+  environment:
+    PGPASSWORD: "{{ patroni_superuser_password }}"
+  when:
+    - pgbouncer_install | bool
+    - pgbouncer_pool_pause | bool
+    - pgbouncer_processes | default(1) | int == 1
+
+- name: '[Pre-Check] Test PgBouncer access via unix socket'
+  ansible.builtin.command: >-
+    psql -h /var/run/pgbouncer{{ '-%d' % (idx + 1) if idx > 0 else '' }}
+    -p {{ pgbouncer_listen_port }}
+    -U {{ patroni_superuser_username }}
+    -d pgbouncer
+    -tAXc "SHOW POOLS"
+  loop: "{{ range(0, (pgbouncer_processes | default(1) | int)) | list }}"
+  loop_control:
+    index_var: idx
+    label: "{{ 'pgbouncer' if idx == 0 else 'pgbouncer-%d' % (idx + 1) }}"
   changed_when: false
+  environment:
+    PGPASSWORD: "{{ patroni_superuser_password }}"
   when:
     - pgbouncer_install | bool
     - pgbouncer_pool_pause | bool
+    - pgbouncer_processes | default(1) | int > 1
 
 # Check the VIP address
 - name: Make sure that the cluster ip address (VIP) "{{ cluster_vip }}" is running