kubernetes_use_configmap (#887)

* kubernetes_use_configmap

* Update manifests/postgresql-operator-default-configuration.yaml

Co-Authored-By: Felix Kunde <felix-kunde@gmx.de>

* Update manifests/configmap.yaml

Co-Authored-By: Felix Kunde <felix-kunde@gmx.de>

* Update charts/postgres-operator/values.yaml

Co-Authored-By: Felix Kunde <felix-kunde@gmx.de>

* go.fmt

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

charts/postgres-operator/crds/operatorconfigurations.yaml

@@ -66,6 +66,8 @@ spec:
               type: boolean
             etcd_host:
               type: string
+            kubernetes_use_configmaps:
+              type: boolean
             max_instances:
               type: integer
               minimum: -1  # -1 = disabled

charts/postgres-operator/values-crd.yaml

@@ -23,6 +23,8 @@ configGeneral:
   enable_shm_volume: true
   # etcd connection string for Patroni. Empty uses K8s-native DCS.
   etcd_host: ""
+  # Select if setup uses endpoints (default), or configmaps to manage leader (DCS=k8s)
+  # kubernetes_use_configmaps: false
   # Spilo docker image
   docker_image: registry.opensource.zalan.do/acid/spilo-12:1.6-p2
   # max number of instances in Postgres cluster. -1 = no limit

charts/postgres-operator/values.yaml

@@ -23,6 +23,8 @@ configGeneral:
   enable_shm_volume: "true"
   # etcd connection string for Patroni. Empty uses K8s-native DCS.
   etcd_host: ""
+  # Select if setup uses endpoints (default), or configmaps to manage leader (DCS=k8s)
+  # kubernetes_use_configmaps: "false"
   # Spilo docker image
   docker_image: registry.opensource.zalan.do/acid/spilo-12:1.6-p2
   # max number of instances in Postgres cluster. -1 = no limit

docs/reference/operator_parameters.md

@@ -80,6 +80,12 @@ Those are top-level keys, containing both leaf keys and groups.
   Patroni native Kubernetes support is used. The default is empty (use
   Kubernetes-native DCS).
 
+* **kubernetes_use_configmaps**
+  Select if setup uses endpoints (default), or configmaps to manage leader when
+  DCS is kubernetes (not etcd or similar). In OpenShift it is not possible to
+  use endpoints option, and configmaps is required. By default, 
+  `kubernetes_use_configmaps: false`, meaning endpoints will be used.
+
 * **docker_image**
   Spilo Docker image for Postgres instances. For production, don't rely on the
   default image, as it might be not the most up-to-date one. Instead, build

manifests/configmap.yaml

@@ -43,6 +43,7 @@ data:
   # enable_team_superuser: "false"
   enable_teams_api: "false"
   # etcd_host: ""
+  # kubernetes_use_configmaps: "false"
   # infrastructure_roles_secret_name: postgresql-infrastructure-roles
   # inherited_labels: application,environment
   # kube_iam_role: ""

manifests/operatorconfiguration.crd.yaml

@@ -42,6 +42,8 @@ spec:
               type: boolean
             etcd_host:
               type: string
+            kubernetes_use_configmaps:
+              type: boolean
             max_instances:
               type: integer
               minimum: -1  # -1 = disabled

manifests/postgresql-operator-default-configuration.yaml

@@ -5,6 +5,7 @@ metadata:
 configuration:
   # enable_crd_validation: true
   etcd_host: ""
+  # kubernetes_use_configmaps: false
   docker_image: registry.opensource.zalan.do/acid/spilo-12:1.6-p2
   # enable_shm_volume: true
   max_instances: -1

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

@@ -727,6 +727,9 @@ var OperatorConfigCRDResourceValidation = apiextv1beta1.CustomResourceValidation
 					"etcd_host": {
 						Type: "string",
 					},
+					"kubernetes_use_configmaps": {
+						Type: "boolean",
+					},
 					"max_instances": {
 						Type:        "integer",
 						Description: "-1 = disabled",

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

@@ -183,6 +183,7 @@ type OperatorLogicalBackupConfiguration struct {
 type OperatorConfigurationData struct {
 	EnableCRDValidation        *bool                              `json:"enable_crd_validation,omitempty"`
 	EtcdHost                   string                             `json:"etcd_host,omitempty"`
+	KubernetesUseConfigMaps    bool                               `json:"kubernetes_use_configmaps,omitempty"`
 	DockerImage                string                             `json:"docker_image,omitempty"`
 	Workers                    uint32                             `json:"workers,omitempty"`
 	MinInstances               int32                              `json:"min_instances,omitempty"`

pkg/cluster/k8sres.go

@@ -672,6 +672,10 @@ func (c *Cluster) generateSpiloPodEnvVars(uid types.UID, spiloConfiguration stri
 		envVars = append(envVars, v1.EnvVar{Name: "ETCD_HOST", Value: c.OpConfig.EtcdHost})
 	}
 
+	if c.patroniKubernetesUseConfigMaps() {
+		envVars = append(envVars, v1.EnvVar{Name: "KUBERNETES_USE_CONFIGMAPS", Value: "true"})
+	}
+
 	if cloneDescription.ClusterName != "" {
 		envVars = append(envVars, c.generateCloneEnvironment(cloneDescription)...)
 	}
@@ -1406,7 +1410,7 @@ func (c *Cluster) generateService(role PostgresRole, spec *acidv1.PostgresSpec)
 		Type:  v1.ServiceTypeClusterIP,
 	}
 
-	if role == Replica {
+	if role == Replica || c.patroniKubernetesUseConfigMaps() {
 		serviceSpec.Selector = c.roleLabelsSet(false, role)
 	}
 

pkg/cluster/util.go

@@ -510,6 +510,15 @@ func (c *Cluster) patroniUsesKubernetes() bool {
 	return c.OpConfig.EtcdHost == ""
 }
 
+func (c *Cluster) patroniKubernetesUseConfigMaps() bool {
+	if !c.patroniUsesKubernetes() {
+		return false
+	}
+
+	// otherwise, follow the operator configuration
+	return c.OpConfig.KubernetesUseConfigMaps
+}
+
 func (c *Cluster) needConnectionPoolerWorker(spec *acidv1.PostgresSpec) bool {
 	if spec.EnableConnectionPooler == nil {
 		return spec.ConnectionPooler != nil

pkg/controller/operator_config.go

@@ -35,6 +35,7 @@ func (c *Controller) importConfigurationFromCRD(fromCRD *acidv1.OperatorConfigur
 	// general config
 	result.EnableCRDValidation = fromCRD.EnableCRDValidation
 	result.EtcdHost = fromCRD.EtcdHost
+	result.KubernetesUseConfigMaps = fromCRD.KubernetesUseConfigMaps
 	result.DockerImage = fromCRD.DockerImage
 	result.Workers = fromCRD.Workers
 	result.MinInstances = fromCRD.MinInstances

pkg/util/config/config.go

@@ -108,6 +108,7 @@ type Config struct {
 	ConnectionPooler
 
 	WatchedNamespace        string            `name:"watched_namespace"` // special values: "*" means 'watch all namespaces', the empty string "" means 'watch a namespace where operator is deployed to'
+	KubernetesUseConfigMaps bool              `name:"kubernetes_use_configmaps" default:"false"`
 	EtcdHost                string            `name:"etcd_host" default:""` // special values: the empty string "" means Patroni will use K8s as a DCS
 	DockerImage             string            `name:"docker_image" default:"registry.opensource.zalan.do/acid/spilo-12:1.6-p2"`
 	Sidecars                map[string]string `name:"sidecar_docker_images"`