From 03157f74a5b0e10cc992142515cab7f784ac6afc Mon Sep 17 00:00:00 2001
From: Vitaliy Kukharik <37010174+vitabaks@users.noreply.github.com>
Date: Fri, 6 Dec 2024 22:04:41 +0500
Subject: [PATCH] Add Upgrade Support for Standby Cluster (#830)

We have now automated the upgrade process for the Patroni Standby Cluster. This allows us to perform upgrades on the cluster copy without impacting the main cluster.

However, this approach requires a preliminary (manual) shutdown of traffic to the main cluster to ensure no recent data changes are lost.
---
 .github/workflows/molecule_pg_upgrade.yml     |  5 +--
 automation/roles/upgrade/README.md            | 18 ++---------
 .../roles/upgrade/tasks/update_config.yml     | 31 +++++++------------
 3 files changed, 15 insertions(+), 39 deletions(-)

diff --git a/.github/workflows/molecule_pg_upgrade.yml b/.github/workflows/molecule_pg_upgrade.yml
index d68632623..3dbb4e013 100644
--- a/.github/workflows/molecule_pg_upgrade.yml
+++ b/.github/workflows/molecule_pg_upgrade.yml
@@ -18,15 +18,12 @@ jobs:
           - distro: debian11
             tag: latest
             namespace: geerlingguy
-          - distro: debian10
+          - distro: ubuntu2404
             tag: latest
             namespace: geerlingguy
           - distro: ubuntu2204
             tag: latest
             namespace: geerlingguy
-          - distro: ubuntu2004
-            tag: latest
-            namespace: geerlingguy
           - distro: rockylinux8
             tag: latest
             namespace: geerlingguy
diff --git a/automation/roles/upgrade/README.md b/automation/roles/upgrade/README.md
index f3060c0d6..80fb2d0c9 100644
--- a/automation/roles/upgrade/README.md
+++ b/automation/roles/upgrade/README.md
@@ -187,22 +187,10 @@ Please see the variable file vars/[upgrade.yml](../../vars/upgrade.yml)
 - Backup the patroni.yml configuration file
 - Edit the patroni.yml configuration file
   - **Update parameters**: `data_dir`, `bin_dir`, `config_dir`
-  - **Check if the 'standby_cluster' parameter is specified**
-    - Remove parameters: `standby_cluster` (if exists)
+  - **Prepare the PostgreSQL parameters**
+    - Notes: Removed or renamed parameters
+  - **Remove 'standby_cluster' parameter (if exists)**
     - Notes: To support upgrades in the Patroni Standby Cluster
-  - **Prepare the PostgreSQL parameters** (removed or renamed parameters)
-    - Check if the '`replacement_sort_tuples`' parameter is specified (removed in PG 11)
-      - remove parameter: 'replacement_sort_tuples' (if exists)
-    - Check if the '`default_with_oids`' parameter is specified (removed in PG 12)
-      - remove parameter: 'default_with_oids' (if exists)
-    - Check if the '`wal_keep_segments`' parameter is specified (removed in PG 13)
-      - replace parameter: 'wal_keep_segments' to '`wal_keep_size`'
-    - Check if the '`operator_precedence_warning`' parameter is specified" (removed in PG 14)
-      - remove parameter: 'operator_precedence_warning' (if exists)
-    - Check if the '`vacuum_cleanup_index_scale_factor`' parameter is specified (removed in PG 14)
-      - remove parameter: 'vacuum_cleanup_index_scale_factor' (if exists)
-    - Check if the '`stats_temp_directory`' parameter is specified (removed in PG 15)
-      - remove parameter: 'stats_temp_directory' (if exists)
 - **Copy pg_hba.conf to `pg_new_confdir`**
   - Notes: to save pg_hba rules
 
diff --git a/automation/roles/upgrade/tasks/update_config.yml b/automation/roles/upgrade/tasks/update_config.yml
index 1b5b863f6..5b343af8f 100644
--- a/automation/roles/upgrade/tasks/update_config.yml
+++ b/automation/roles/upgrade/tasks/update_config.yml
@@ -25,26 +25,6 @@
   loop_control:
     label: '{{ item.replace }}'
 
-# To support upgrades in the Patroni Standby Cluster.
-- block:  # standby_cluster
-    - name: "Edit patroni.yml | check if the 'standby_cluster' parameter is specified"
-      ansible.builtin.command: grep standby_cluster {{ patroni_config_file }}
-      register: standby_cluster_output
-      changed_when: false
-      failed_when: false
-
-    # The standby_cluster parameter will be removed from the bootstrap.dcs section (if exists)
-    # along with all the text between 'standby_cluster' and the next 'initdb' parameter
-    - name: "Edit patroni.yml | remove parameters: standby_cluster (if exists)"
-      ansible.builtin.replace:
-        path: "{{ patroni_config_file }}"
-        regexp: '^\s*standby_cluster:[^\n]*\n(.|\n)*?initdb:'
-        replace: '  initdb:'
-      when: standby_cluster_output.stdout | length > 0
-  when:
-    - patroni_standby_cluster.host is defined
-    - patroni_standby_cluster.host | length > 0
-
 # Prepare the parameters for PostgreSQL (removed or renamed parameters).
 
 - block:  # replacement_sort_tuples (removed in the PG 11)
@@ -269,6 +249,17 @@
 
 # TODO: Prepare the parameters for PostgreSQL 18 and etc.
 
+# To support upgrades in the Patroni Standby Cluster.
+- name: "Edit patroni.yml | remove parameter: standby_cluster (if exists)"
+  ansible.builtin.replace:
+    path: "{{ patroni_config_file }}"
+    regexp: '^\s*standby_cluster:[^\n]*\n(.|\n)*?initdb:'
+    replace: '  initdb:'
+
+- name: "Remove 'standby_cluster' parameter from DCS (if exists)"
+  ansible.builtin.command: patronictl -c {{ patroni_config_file }} edit-config -s standby_cluster=null --force
+  when: inventory_hostname in groups['primary']
+
 # Copy the pg_hba.conf file to a new PostgreSQL to save pg_hba rules.
 - name: "Copy pg_hba.conf to {{ pg_new_confdir }}"
   ansible.builtin.copy: