Implement backward compatibility with older load balancer settings

README.md

@@ -237,6 +237,8 @@ For instance, of a cluster manifest has 1 instance and the min_instances is set
 
 For any Postgresql/Spilo cluster an operator creates two separate k8s services: one for the master pod and one for replica pods. To expose these services to an outer network, one can attach load balancers to them by setting `enableMasterLoadBalancer` and/or `enableReplicaLoadBalancer` to `true` in the cluster manifest. In the case any of these variables is omitted from the manifest, the operator configmap's settings `enable_master_load_balancer` and `enable_replica_load_balancer` apply. Note that the operator settings affect all Postgresql services running in a namespace watched by the operator.
 
+For backward compatibility with already configured clusters we maintain in a cluster manifest older parameter names, namely `useLoadBalancer` for enabling the master service's load balancer and `replicaLoadBalancer` for the replica service. If set, these params take precedence over the newer `enableMasterLoadBalancer` and `enableReplicaLoadBalancer`. Note that in older versions of the operator (before PR #258) `replicaLoadBalancer` was responsible for both creating the replica service and attaching an LB to it; now the service is always created (since k8s service typically is free in the cloud setting), and this param only attaches an LB (that typically costs money).
+
 # Setup development environment
 
 The following steps guide you through the setup to work on the operator itself.

pkg/cluster/k8sres.go

@@ -675,18 +675,31 @@ func (c *Cluster) shouldCreateLoadBalancerForService(role PostgresRole, spec *sp
 
 	case Replica:
 
+		// deprecated option takes priority for backward compatibility
+		if spec.ReplicaLoadBalancer != nil {
+			c.logger.Debugf("The Postgres manifest for the cluster %v sets the deprecated `replicaLoadBalancer` param. Consider using the `enableReplicaLoadBalancer` instead.", c.Name)
+			return *spec.ReplicaLoadBalancer
+		}
+
 		// if the value is explicitly set in a Postgresql manifest, follow this setting
 		if spec.EnableReplicaLoadBalancer != nil {
 			return *spec.EnableReplicaLoadBalancer
 		}
+
 		// otherwise, follow the operator configuration
 		return c.OpConfig.EnableReplicaLoadBalancer
 
 	case Master:
 
+		if spec.UseLoadBalancer != nil {
+			c.logger.Debugf("The Postgres manifest for the cluster %v sets the deprecated `useLoadBalancer` param. Consider using the `enableMasterLoadBalancer` instead.", c.Name)
+			return *spec.UseLoadBalancer
+		}
+
 		if spec.EnableMasterLoadBalancer != nil {
 			return *spec.EnableMasterLoadBalancer
 		}
+
 		return c.OpConfig.EnableMasterLoadBalancer
 
 	default:

pkg/spec/postgresql.go

@@ -96,17 +96,24 @@ type PostgresSpec struct {
 	TeamID              string   `json:"teamId"`
 	AllowedSourceRanges []string `json:"allowedSourceRanges"`
 	DockerImage         string   `json:"dockerImage,omitempty"`
+
 	// vars that enable load balancers are pointers because it is important to know if any of them is omitted from the Postgres manifest
 	// in that case the var evaluates to nil and the value is taken from the operator config
-	EnableMasterLoadBalancer  *bool                `json:"enableMasterLoadBalancer,omitempty"`
-	EnableReplicaLoadBalancer *bool                `json:"enableReplicaLoadBalancer,omitempty"`
-	NumberOfInstances         int32                `json:"numberOfInstances"`
-	Users                     map[string]UserFlags `json:"users"`
-	MaintenanceWindows        []MaintenanceWindow  `json:"maintenanceWindows,omitempty"`
-	Clone                     CloneDescription     `json:"clone"`
-	ClusterName               string               `json:"-"`
-	Databases                 map[string]string    `json:"databases,omitempty"`
-	Tolerations               []v1.Toleration      `json:"tolerations,omitempty"`
+	EnableMasterLoadBalancer  *bool `json:"enableMasterLoadBalancer,omitempty"`
+	EnableReplicaLoadBalancer *bool `json:"enableReplicaLoadBalancer,omitempty"`
+
+	// deprecated load balancer settings mantained for backward compatibility
+	// see "Load balancers" operator docs (PR #258)
+	UseLoadBalancer     *bool `json:"useLoadBalancer,omitempty"`
+	ReplicaLoadBalancer *bool `json:"replicaLoadBalancer,omitempty"`
+
+	NumberOfInstances  int32                `json:"numberOfInstances"`
+	Users              map[string]UserFlags `json:"users"`
+	MaintenanceWindows []MaintenanceWindow  `json:"maintenanceWindows,omitempty"`
+	Clone              CloneDescription     `json:"clone"`
+	ClusterName        string               `json:"-"`
+	Databases          map[string]string    `json:"databases,omitempty"`
+	Tolerations        []v1.Toleration      `json:"tolerations,omitempty"`
 }
 
 // PostgresqlList defines a list of PostgreSQL clusters.