postgres: option to enable quorum-based replication

Signed-off-by: Andrei Kvapil <kvapss@gmail.com>

packages/apps/postgres/Chart.yaml

@@ -16,7 +16,7 @@ type: application
 # This is the chart version. This version number should be incremented each time you make changes
 # to the chart and its templates, including the app version.
 # Versions are expected to follow Semantic Versioning (https://semver.org/)
-version: 0.2.1
+version: 0.3.0
 
 # This is the version number of the application being deployed. This version number should be
 # incremented each time you make changes to the application. Versions are not expected to

packages/apps/postgres/README.md

@@ -35,11 +35,13 @@ more details:
 
 ### Common parameters
 
-| Name       | Description                                     | Value   |
-| ---------- | ----------------------------------------------- | ------- |
-| `external` | Enable external access from outside the cluster | `false` |
-| `size`     | Persistent Volume size                          | `10Gi`  |
-| `replicas` | Number of MariaDB replicas                      | `2`     |
+| Name                     | Description                                                                                                             | Value   |
+| ------------------------ | ----------------------------------------------------------------------------------------------------------------------- | ------- |
+| `external`               | Enable external access from outside the cluster                                                                         | `false` |
+| `size`                   | Persistent Volume size                                                                                                  | `10Gi`  |
+| `replicas`               | Number of Postgres replicas                                                                                             | `2`     |
+| `quorum.minSyncReplicas` | Minimum number of synchronous replicas that must acknowledge a transaction before it is considered committed.           | `0`     |
+| `quorum.maxSyncReplicas` | Maximum number of synchronous replicas that can acknowledge a transaction (must be lower than the number of instances). | `0`     |
 
 ### Configuration parameters
 

packages/apps/postgres/templates/db.yaml

@@ -11,6 +11,9 @@ spec:
     parameters:
       max_wal_senders: "30"
 
+  minSyncReplicas: {{ .Values.quorum.minSyncReplicas }}
+  maxSyncReplicas: {{ .Values.quorum.maxSyncReplicas }}
+
   monitoring:
     enablePodMonitor: true
 

packages/apps/postgres/values.schema.json

@@ -14,9 +14,24 @@
         },
         "replicas": {
             "type": "number",
-            "description": "Number of MariaDB replicas",
+            "description": "Number of Postgres replicas",
             "default": 2
         },
+        "quorum": {
+            "type": "object",
+            "properties": {
+                "minSyncReplicas": {
+                    "type": "number",
+                    "description": "Minimum number of synchronous replicas that must acknowledge a transaction before it is considered committed.",
+                    "default": 0
+                },
+                "maxSyncReplicas": {
+                    "type": "number",
+                    "description": "Maximum number of synchronous replicas that can acknowledge a transaction (must be lower than the number of instances).",
+                    "default": 0
+                }
+            }
+        },
         "databases": {
             "type": "object",
             "description": "Databases configuration",

packages/apps/postgres/values.yaml

@@ -2,12 +2,19 @@
 
 ## @param external Enable external access from outside the cluster
 ## @param size Persistent Volume size
-## @param replicas Number of MariaDB replicas
+## @param replicas Number of Postgres replicas
 ##
 external: false
 size: 10Gi
 replicas: 2
 
+## Configuration for the quorum-based synchronous replication
+## @param quorum.minSyncReplicas Minimum number of synchronous replicas that must acknowledge a transaction before it is considered committed.
+## @param quorum.maxSyncReplicas Maximum number of synchronous replicas that can acknowledge a transaction (must be lower than the number of instances).
+quorum:
+  minSyncReplicas: 0
+  maxSyncReplicas: 0
+
 ## @section Configuration parameters
 
 ## @param users [object] Users configuration

packages/apps/versions_map

@@ -14,7 +14,8 @@ mysql 0.2.0 8b975ff0
 mysql 0.3.0 HEAD
 postgres 0.1.0 f642698
 postgres 0.2.0 7cd7de73
-postgres 0.2.1 HEAD
+postgres 0.2.1 4a97e297
+postgres 0.3.0 HEAD
 rabbitmq 0.1.0 f642698
 rabbitmq 0.2.0 HEAD
 redis 0.1.1 f642698