Allow conversion master-standby to patroni cluster

Support the deployment of cluster over already existing and running PostgreSQL, including Replica (standby) servers.

You can convert the basic replication configuration to the Patroni cluster.

Specify the variable postgresql_exists='true' in inventory file, and postgresql_version, postgresql_data_dir variables (how in current servers) in vars/Debian.yml (or RedHat.yml).

Author: vitabaks

inventory

@@ -2,7 +2,7 @@
 # Please specify the ip addresses and connection settings for your environment
 # The specified ip addresses will be used to listen by the cluster components.
 
-# "postgresql_exists='true'" if PostgreSQL is already exists and running on master (for initial deployment only)
+# "postgresql_exists='true'" if PostgreSQL is already exists and running
 # "hostname=" variable is optional (used to change the server name)
 
 # if dcs_exists: false and dcs_type: "etcd" (in vars/main.yml)
@@ -24,8 +24,8 @@
 10.128.64.140 hostname=pgnode01 postgresql_exists='false'
 
 [replica]
-10.128.64.142 hostname=pgnode02
-10.128.64.143 hostname=pgnode03
+10.128.64.142 hostname=pgnode02 postgresql_exists='false'
+10.128.64.143 hostname=pgnode03 postgresql_exists='false'
 
 [postgres_cluster:children]
 master

roles/patroni/tasks/main.yml

@@ -362,139 +362,6 @@
   when: postgresql_wal_dir is defined and postgresql_wal_dir | length > 0
   tags: patroni, custom_wal_dir
 
-- block:  # when postgresql exists (master)
-    - name: Prepare PostgreSQL | check that data directory "{{ postgresql_data_dir }}" is initialized on Master
-      stat:
-        path: "{{ postgresql_data_dir }}/PG_VERSION"
-      register: pgdata_initialized
-
-    - name: Prepare PostgreSQL | data directory check result
-      fail:
-        msg: "Whoops! data directory {{ postgresql_data_dir }} is not initialized"
-      when: not pgdata_initialized.stat.exists
-      tags: patroni, patroni_check_init
-
-    - name: Prepare PostgreSQL | check PostgreSQL is started
-      become: true
-      become_user: postgres
-      command: "{{ postgresql_bin_dir }}/pg_ctl status -D {{ postgresql_data_dir }}"
-      register: pg_ctl_status_result
-      changed_when: false
-      failed_when:
-        - pg_ctl_status_result.rc != 0
-        - pg_ctl_status_result.rc != 3
-
-      # "Debian"
-    - name: Prepare PostgreSQL | start PostgreSQL
-      become: true
-      become_user: postgres
-      command: "/usr/bin/pg_ctlcluster {{ postgresql_version }} {{ postgresql_cluster_name }} start"
-      when: pg_ctl_status_result.rc == 3 and
-            ansible_os_family == "Debian"
-
-      # "RedHat" or PostgresPro
-    - name: Prepare PostgreSQL | start PostgreSQL
-      become: true
-      become_user: postgres
-      command: "{{ postgresql_bin_dir }}/pg_ctl start -D {{ postgresql_data_dir }}"
-      when: pg_ctl_status_result.rc == 3 and
-            (ansible_os_family == "RedHat" or
-            postgresql_packages|join(" ") is search("postgrespro"))
-
-    - name: Prepare PostgreSQL | check PostgreSQL is accepting connections
-      become: true
-      become_user: postgres
-      command: "{{ postgresql_bin_dir }}/pg_isready -p {{ postgresql_port }}"
-      register: pg_isready_result
-      until: pg_isready_result.rc == 0
-      retries: 30
-      delay: 10
-      changed_when: false
-
-    - name: Prepare PostgreSQL | generate pg_hba.conf on Master
-      template:
-        src: templates/pg_hba.conf.j2
-        dest: "{{ postgresql_conf_dir }}/pg_hba.conf"
-        owner: postgres
-        group: postgres
-        mode: 0640
-
-    - name: Prepare PostgreSQL | reload for apply the pg_hba.conf
-      become: true
-      become_user: postgres
-      command: "{{ postgresql_bin_dir }}/psql -p {{ postgresql_port }} -c 'SELECT pg_reload_conf()'"
-      register: psql_reload_result
-      failed_when: psql_reload_result.rc != 0
-
-    - name: Prepare PostgreSQL | make sure the user "{{ patroni_superuser_username }}" are present, and password does not differ from the specified
-      postgresql_user:
-        db: postgres
-        name: "{{ patroni_superuser_username }}"
-        password: "{{ patroni_superuser_password }}"
-        encrypted: true
-        role_attr_flags: "SUPERUSER"
-        login_unix_socket: "{{ postgresql_unix_socket_dir }}"
-        port: "{{ postgresql_port }}"
-        state: present
-      become: true
-      become_user: postgres
-
-    - name: Prepare PostgreSQL | make sure the user "{{ patroni_replication_username }}" are present, and password does not differ from the specified
-      postgresql_user:
-        db: postgres
-        name: "{{ patroni_replication_username }}"
-        password: "{{ patroni_replication_password }}"
-        encrypted: true
-        role_attr_flags: "LOGIN,REPLICATION"
-        login_unix_socket: "{{ postgresql_unix_socket_dir }}"
-        port: "{{ postgresql_port }}"
-        state: present
-      become: true
-      become_user: postgres
-
-    - name: Prepare PostgreSQL | waiting for CHECKPOINT to complete before stopping postgresql
-      become: true
-      become_user: postgres
-      command: "{{ postgresql_bin_dir }}/psql -p {{ postgresql_port }} -c 'CHECKPOINT'"
-      register: checkpoint_result
-      until: checkpoint_result.rc == 0
-      retries: 180
-      delay: 15
-
-      # "Debian"
-    - name: Prepare PostgreSQL | stop PostgreSQL (will be managed by patroni)
-      become: true
-      become_user: postgres
-      command: "/usr/bin/pg_ctlcluster {{ postgresql_version }} {{ postgresql_cluster_name }} stop -m fast"
-      register: stop_result
-      until: stop_result.rc == 0
-      retries: 10
-      delay: 30
-      when: ansible_os_family == "Debian" and
-            postgresql_packages|join(" ") is not search("postgrespro")
-
-      # "RedHat" or PostgresPro
-    - name: Prepare PostgreSQL | stop PostgreSQL (will be managed by patroni)
-      become: true
-      become_user: postgres
-      command: "{{ postgresql_bin_dir }}/pg_ctl stop -D {{ postgresql_data_dir }} -m fast"
-      register: stop_result
-      until: stop_result.rc == 0
-      retries: 30
-      delay: 10
-      when: ansible_os_family == "RedHat" or
-            postgresql_packages|join(" ") is search("postgrespro")
-
-    - name: Prepare PostgreSQL | check PostgreSQL is stopped
-      become: true
-      become_user: postgres
-      command: "{{ postgresql_bin_dir }}/pg_ctl status -D {{ postgresql_data_dir }}"
-      register: pg_ctl_stop_result
-      failed_when: pg_ctl_stop_result.rc != 3
-      changed_when: false
-  when: is_master == "true" and postgresql_exists == "true"
-  tags: patroni, patroni_start_master
-
 - block:  # wheh postgresql NOT exists or PITR
     - name: Prepare PostgreSQL | make sure PostgreSQL data directory "{{ postgresql_data_dir }}" exists
       file:
@@ -565,9 +432,156 @@
         - directory
       when: (postgresql_wal_dir is defined and postgresql_wal_dir | length > 0) and
             patroni_cluster_bootstrap_method != "pgbackrest"  # --delta restore
-  when: postgresql_exists != "true"
+  when: postgresql_exists != "true" or patroni_cluster_bootstrap_method != "initdb"
   tags: patroni, point_in_time_recovery
 
+- block:  # when postgresql exists
+    - name: Prepare PostgreSQL | check that data directory "{{ postgresql_data_dir }}" is initialized
+      stat:
+        path: "{{ postgresql_data_dir }}/PG_VERSION"
+      register: pgdata_initialized
+
+    - name: Prepare PostgreSQL | data directory check result
+      fail:
+        msg: "Whoops! data directory {{ postgresql_data_dir }} is not initialized"
+      when: not pgdata_initialized.stat.exists
+      tags: patroni, patroni_check_init
+
+    - block:  # for master only
+        - name: Prepare PostgreSQL | check PostgreSQL is started on Master
+          become: true
+          become_user: postgres
+          command: "{{ postgresql_bin_dir }}/pg_ctl status -D {{ postgresql_data_dir }}"
+          register: pg_ctl_status_result
+          changed_when: false
+          failed_when:
+            - pg_ctl_status_result.rc != 0
+            - pg_ctl_status_result.rc != 3
+
+          # "Debian"
+        - name: Prepare PostgreSQL | start PostgreSQL on Master
+          become: true
+          become_user: postgres
+          command: "/usr/bin/pg_ctlcluster {{ postgresql_version }} {{ postgresql_cluster_name }} start"
+          register: pg_start_on_master
+          when: pg_ctl_status_result.rc == 3 and
+                (ansible_os_family == "Debian" and postgresql_packages|join(" ") is not search("postgrespro"))
+
+          # "RedHat" or PostgresPro
+        - name: Prepare PostgreSQL | start PostgreSQL on Master
+          become: true
+          become_user: postgres
+          command: "{{ postgresql_bin_dir }}/pg_ctl start -D {{ postgresql_data_dir }}"
+          register: pg_start_on_master
+          when: pg_ctl_status_result.rc == 3 and
+                (ansible_os_family == "RedHat" or postgresql_packages|join(" ") is search("postgrespro"))
+
+        - name: Prepare PostgreSQL | check PostgreSQL is accepting connections
+          become: true
+          become_user: postgres
+          command: "{{ postgresql_bin_dir }}/pg_isready -p {{ postgresql_port }}"
+          register: pg_isready_result
+          until: pg_isready_result.rc == 0
+          retries: 30
+          delay: 10
+          changed_when: false
+
+        - name: Prepare PostgreSQL | generate pg_hba.conf on Master
+          template:
+            src: templates/pg_hba.conf.j2
+            dest: "{{ postgresql_conf_dir }}/pg_hba.conf"
+            owner: postgres
+            group: postgres
+            mode: 0640
+
+        - name: Prepare PostgreSQL | reload for apply the pg_hba.conf
+          become: true
+          become_user: postgres
+          command: "{{ postgresql_bin_dir }}/psql -p {{ postgresql_port }} -c 'SELECT pg_reload_conf()'"
+          register: psql_reload_result
+          failed_when: psql_reload_result.rc != 0
+
+        - name: Prepare PostgreSQL | make sure the user "{{ patroni_superuser_username }}" are present, and password does not differ from the specified
+          postgresql_user:
+            db: postgres
+            name: "{{ patroni_superuser_username }}"
+            password: "{{ patroni_superuser_password }}"
+            encrypted: true
+            role_attr_flags: "SUPERUSER"
+            login_unix_socket: "{{ postgresql_unix_socket_dir }}"
+            port: "{{ postgresql_port }}"
+            state: present
+          become: true
+          become_user: postgres
+
+        - name: Prepare PostgreSQL | make sure the user "{{ patroni_replication_username }}" are present, and password does not differ from the specified
+          postgresql_user:
+            db: postgres
+            name: "{{ patroni_replication_username }}"
+            password: "{{ patroni_replication_password }}"
+            encrypted: true
+            role_attr_flags: "LOGIN,REPLICATION"
+            login_unix_socket: "{{ postgresql_unix_socket_dir }}"
+            port: "{{ postgresql_port }}"
+            state: present
+          become: true
+          become_user: postgres
+      when: is_master == "true"
+
+    - name: Prepare PostgreSQL | check PostgreSQL is started
+      become: true
+      become_user: postgres
+      command: "{{ postgresql_bin_dir }}/pg_ctl status -D {{ postgresql_data_dir }}"
+      register: pg_ctl_status_result
+      changed_when: false
+      failed_when:
+        - pg_ctl_status_result.rc != 0
+        - pg_ctl_status_result.rc != 3
+
+    - name: Prepare PostgreSQL | waiting for CHECKPOINT to complete before stopping postgresql
+      become: true
+      become_user: postgres
+      command: "{{ postgresql_bin_dir }}/psql -p {{ postgresql_port }} -c 'CHECKPOINT'"
+      register: checkpoint_result
+      until: checkpoint_result.rc == 0
+      retries: 300
+      delay: 10
+      when: pg_ctl_status_result.rc == 0
+
+      # "Debian"
+    - name: Prepare PostgreSQL | stop PostgreSQL (will be managed by patroni)
+      become: true
+      become_user: postgres
+      command: "/usr/bin/pg_ctlcluster {{ postgresql_version }} {{ postgresql_cluster_name }} stop -m fast"
+      register: stop_result
+      until: stop_result.rc == 0
+      retries: 300
+      delay: 10
+      when: (checkpoint_result.rc is defined and checkpoint_result.rc == 0) and
+            (ansible_os_family == "Debian" and postgresql_packages|join(" ") is not search("postgrespro"))
+
+      # "RedHat" or PostgresPro
+    - name: Prepare PostgreSQL | stop PostgreSQL (will be managed by patroni)
+      become: true
+      become_user: postgres
+      command: "{{ postgresql_bin_dir }}/pg_ctl stop -D {{ postgresql_data_dir }} -m fast"
+      register: stop_result
+      until: stop_result.rc == 0
+      retries: 300
+      delay: 10
+      when: (checkpoint_result.rc is defined and checkpoint_result.rc == 0) and
+            (ansible_os_family == "RedHat" or postgresql_packages|join(" ") is search("postgrespro"))
+
+    - name: Prepare PostgreSQL | check PostgreSQL is stopped
+      become: true
+      become_user: postgres
+      command: "{{ postgresql_bin_dir }}/pg_ctl status -D {{ postgresql_data_dir }}"
+      register: pg_ctl_stop_result
+      failed_when: pg_ctl_stop_result.rc != 3
+      changed_when: false
+  when: postgresql_exists == "true" and patroni_cluster_bootstrap_method == "initdb"
+  tags: patroni, patroni_start_master
+
 - block:  # PITR (custom bootstrap)
 # Prepare (install pexpect, ruamel.yaml)
     - name: Prepare | Make sure the ansible required python library is exist