synchronous_node_count support (#1484)

* synchronous_node_count support
* notification about Patroni image version
* default synchronous_node_count to 1

Co-authored-by: Felix Kunde <felix-kunde@gmx.de>

charts/postgres-operator/crds/postgresqls.yaml

@@ -343,6 +343,8 @@ spec:
                     type: boolean
                   synchronous_mode_strict:
                     type: boolean
+                  synchronous_node_count:
+                    type: integer
                   ttl:
                     type: integer
               podAnnotations:

docs/reference/cluster_manifest.md

@@ -303,6 +303,9 @@ explanation of `ttl` and `loop_wait` parameters.
 * **synchronous_mode_strict**
   Patroni `synchronous_mode_strict` parameter value. Can be used in addition to `synchronous_mode`. The default is set to `false`. Optional.
 
+* **synchronous_node_count**
+  Patroni `synchronous_node_count` parameter value. Note, this option is only available for Spilo images with Patroni 2.0+. The default is set to `1`. Optional.
+  
 ## Postgres container resources
 
 Those parameters define [CPU and memory requests and limits](https://kubernetes.io/docs/concepts/configuration/manage-compute-resources-container/)

manifests/complete-postgres-manifest.yaml

@@ -119,6 +119,7 @@ spec:
     retry_timeout: 10
     synchronous_mode: false
     synchronous_mode_strict: false
+    synchronous_node_count: 1
     maximum_lag_on_failover: 33554432
 
 # restore a Postgres DB with point-in-time-recovery

manifests/postgresql.crd.yaml

@@ -341,6 +341,8 @@ spec:
                     type: boolean
                   synchronous_mode_strict:
                     type: boolean
+                  synchronous_node_count:
+                    type: integer
                   ttl:
                     type: integer
               podAnnotations:

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

@@ -534,6 +534,9 @@ var PostgresCRDResourceValidation = apiextv1.CustomResourceValidation{
 							"synchronous_mode_strict": {
 								Type: "boolean",
 							},
+							"synchronous_node_count": {
+								Type: "integer",
+							},
 							"ttl": {
 								Type: "integer",
 							},

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

@@ -164,6 +164,7 @@ type Patroni struct {
 	Slots                 map[string]map[string]string `json:"slots,omitempty"`
 	SynchronousMode       bool                         `json:"synchronous_mode,omitempty"`
 	SynchronousModeStrict bool                         `json:"synchronous_mode_strict,omitempty"`
+	SynchronousNodeCount  uint32                       `json:"synchronous_node_count,omitempty" defaults:1`
 }
 
 // StandbyDescription contains s3 wal path

pkg/cluster/k8sres.go

@@ -50,6 +50,7 @@ type patroniDCS struct {
 	MaximumLagOnFailover     float32                      `json:"maximum_lag_on_failover,omitempty"`
 	SynchronousMode          bool                         `json:"synchronous_mode,omitempty"`
 	SynchronousModeStrict    bool                         `json:"synchronous_mode_strict,omitempty"`
+	SynchronousNodeCount     uint32                       `json:"synchronous_node_count,omitempty"`
 	PGBootstrapConfiguration map[string]interface{}       `json:"postgresql,omitempty"`
 	Slots                    map[string]map[string]string `json:"slots,omitempty"`
 }
@@ -262,6 +263,9 @@ PatroniInitDBParams:
 	if patroni.SynchronousModeStrict {
 		config.Bootstrap.DCS.SynchronousModeStrict = patroni.SynchronousModeStrict
 	}
+	if patroni.SynchronousNodeCount >= 1 {
+		config.Bootstrap.DCS.SynchronousNodeCount = patroni.SynchronousNodeCount
+	}
 
 	config.PgLocalConfiguration = make(map[string]interface{})
 

pkg/cluster/k8sres_test.go

@@ -91,11 +91,12 @@ func TestGenerateSpiloJSONConfiguration(t *testing.T) {
 				MaximumLagOnFailover:  33554432,
 				SynchronousMode:       true,
 				SynchronousModeStrict: true,
+				SynchronousNodeCount:  1,
 				Slots:                 map[string]map[string]string{"permanent_logical_1": {"type": "logical", "database": "foo", "plugin": "pgoutput"}},
 			},
 			role:     "zalandos",
 			opConfig: config.Config{},
-			result:   `{"postgresql":{"bin_dir":"/usr/lib/postgresql/11/bin","pg_hba":["hostssl all all 0.0.0.0/0 md5","host    all all 0.0.0.0/0 md5"]},"bootstrap":{"initdb":[{"auth-host":"md5"},{"auth-local":"trust"},"data-checksums",{"encoding":"UTF8"},{"locale":"en_US.UTF-8"}],"users":{"zalandos":{"password":"","options":["CREATEDB","NOLOGIN"]}},"dcs":{"ttl":30,"loop_wait":10,"retry_timeout":10,"maximum_lag_on_failover":33554432,"synchronous_mode":true,"synchronous_mode_strict":true,"slots":{"permanent_logical_1":{"database":"foo","plugin":"pgoutput","type":"logical"}}}}}`,
+			result:   `{"postgresql":{"bin_dir":"/usr/lib/postgresql/11/bin","pg_hba":["hostssl all all 0.0.0.0/0 md5","host    all all 0.0.0.0/0 md5"]},"bootstrap":{"initdb":[{"auth-host":"md5"},{"auth-local":"trust"},"data-checksums",{"encoding":"UTF8"},{"locale":"en_US.UTF-8"}],"users":{"zalandos":{"password":"","options":["CREATEDB","NOLOGIN"]}},"dcs":{"ttl":30,"loop_wait":10,"retry_timeout":10,"maximum_lag_on_failover":33554432,"synchronous_mode":true,"synchronous_mode_strict":true,"synchronous_node_count":1,"slots":{"permanent_logical_1":{"database":"foo","plugin":"pgoutput","type":"logical"}}}}}`,
 		},
 	}
 	for _, tt := range tests {