Allow specifying primary slot for remote standby (#2065)

charts/postgres-operator/crds/postgresqls.yaml

@@ -479,6 +479,8 @@ spec:
                     type: string
                   standby_port:
                     type: string
+                  standby_primary_slot_name:
+                    type: string
                 oneOf:
                 - required:
                   - s3_wal_path

docs/administrator.md

@@ -1156,6 +1156,7 @@ the `STANDBY_` prefix for Spilo to find the backups and WAL files to stream.
 
 Alternatively, standby clusters can also stream from a remote primary cluster.
 You have to specify the host address. Port is optional and defaults to 5432.
+Moreover, you can also specify a replication slot of the primary.
 Note, that only one of the options (`s3_wal_path`, `gs_wal_path`,
 `standby_host`) can be present under the `standby` top-level key.
 

docs/reference/cluster_manifest.md

@@ -430,6 +430,9 @@ if the `standby` key is present.
   TCP port on which the primary is listening for connections. Patroni will
   use `"5432"` if not set.
 
+* **standby_primary_slot_name**
+  replication slot on the primary.
+
 ## Volume properties
 
 Those parameters are grouped under the `volume` top-level key and define the

docs/user.md

@@ -901,6 +901,15 @@ spec:
   standby:
     standby_host: "acid-minimal-cluster.default"
     standby_port: "5433"
+    standby_primary_slot_name: "slot"
+```
+
+If needed, one can also specify the slot on the primary to use for replication.
+
+```yaml
+spec:
+  standby:
+    standby_primary_slot_name: "slot"
 ```
 
 Note, that the pods and services use the same role labels like for normal clusters:

manifests/postgresql.crd.yaml

@@ -477,6 +477,8 @@ spec:
                     type: string
                   standby_port:
                     type: string
+                  standby_primary_slot_name:
+                    type: string
                 oneOf:
                 - required:
                   - s3_wal_path

manifests/standby-manifest.yaml

@@ -14,3 +14,4 @@ spec:
     # s3_wal_path: "s3://mybucket/spilo/acid-minimal-cluster/abcd1234-2a4b-4b2a-8c9c-c1234defg567/wal/14/"
     standby_host: "acid-minimal-cluster.default"
     # standby_port: "5432"
+    # standby_primary_slot_name: "slot"

pkg/apis/acid.zalan.do/v1/crds.go

@@ -746,6 +746,9 @@ var PostgresCRDResourceValidation = apiextv1.CustomResourceValidation{
 							"standby_port": {
 								Type: "string",
 							},
+							"standby_primary_slot_name": {
+								Type: "string",
+							},
 						},
 						OneOf: []apiextv1.JSONSchemaProps{
 							apiextv1.JSONSchemaProps{Required: []string{"s3_wal_path"}},

pkg/apis/acid.zalan.do/v1/postgresql_type.go

@@ -184,6 +184,7 @@ type StandbyDescription struct {
 	GSWalPath              string `json:"gs_wal_path,omitempty"`
 	StandbyHost            string `json:"standby_host,omitempty"`
 	StandbyPort            string `json:"standby_port,omitempty"`
+	StandbyPrimarySlotName string `json:"standby_primary_slot_name,omitempty"`
 }
 
 // TLSDescription specs TLS properties

pkg/cluster/k8sres.go

@@ -2058,6 +2058,12 @@ func (c *Cluster) generateStandbyEnvironment(description *acidv1.StandbyDescript
 				Value: description.StandbyPort,
 			})
 		}
+		if description.StandbyPrimarySlotName != "" {
+			result = append(result, v1.EnvVar{
+				Name:  "STANDBY_PRIMARY_SLOT_NAME",
+				Value: description.StandbyPrimarySlotName,
+			})
+		}
 	} else {
 		c.logger.Info("standby cluster streaming from WAL location")
 		if description.S3WalPath != "" {

pkg/cluster/k8sres_test.go

@@ -1292,6 +1292,19 @@ func TestStandbyEnv(t *testing.T) {
 			envPos: 1,
 			envLen: 2,
 		},
+		{
+			subTest: "from remote primary with slot",
+			standbyOpts: &acidv1.StandbyDescription{
+				StandbyHost: "remote-primary",
+				StandbyPrimarySlotName: "slot",
+			},
+			env: v1.EnvVar{
+				Name:  "STANDBY_PRIMARY_SLOT_NAME",
+				Value: "slot",
+			},
+			envPos: 1,
+			envLen: 2,
+		},
 		{
 			subTest: "from remote primary - ignore WAL path",
 			standbyOpts: &acidv1.StandbyDescription{