Add config switch to share pg_socket in /var/run/postgresql via an emptyDir with the sidecar containers (#962)

pkg/cluster/k8sres.go

@@ -713,6 +713,7 @@ func (c *Cluster) generatePodTemplate(
 	spiloContainer *v1.Container,
 	initContainers []v1.Container,
 	sidecarContainers []v1.Container,
+	sharePGSocketWithSidecars *bool,
 	tolerationsSpec *[]v1.Toleration,
 	spiloRunAsUser *int64,
 	spiloRunAsGroup *int64,
@@ -775,6 +776,10 @@ func (c *Cluster) generatePodTemplate(
 		podSpec.PriorityClassName = priorityClassName
 	}
 
+	if sharePGSocketWithSidecars != nil && *sharePGSocketWithSidecars {
+		addVarRunVolume(&podSpec)
+	}
+
 	if additionalSecretMount != "" {
 		addSecretVolume(&podSpec, additionalSecretMount, additionalSecretMountPath)
 	}
@@ -1357,6 +1362,7 @@ func (c *Cluster) generateStatefulSet(spec *acidv1.PostgresSpec) (*appsv1.Statef
 		spiloContainer,
 		initContainers,
 		sidecarContainers,
+		c.OpConfig.SharePGSocketWithSidecars,
 		&tolerationSpec,
 		effectiveRunAsUser,
 		effectiveRunAsGroup,
@@ -1550,6 +1556,28 @@ func addShmVolume(podSpec *v1.PodSpec) {
 	podSpec.Volumes = volumes
 }
 
+func addVarRunVolume(podSpec *v1.PodSpec) {
+	volumes := append(podSpec.Volumes, v1.Volume{
+		Name: "postgresql-run",
+		VolumeSource: v1.VolumeSource{
+			EmptyDir: &v1.EmptyDirVolumeSource{
+				Medium: "Memory",
+			},
+		},
+	})
+
+	for i := range podSpec.Containers {
+		mounts := append(podSpec.Containers[i].VolumeMounts,
+			v1.VolumeMount{
+				Name:      "postgresql-run",
+				MountPath: "/var/run/postgresql",
+			})
+		podSpec.Containers[i].VolumeMounts = mounts
+	}
+
+	podSpec.Volumes = volumes
+}
+
 func addSecretVolume(podSpec *v1.PodSpec, additionalSecretMount string, additionalSecretMountPath string) {
 	volumes := append(podSpec.Volumes, v1.Volume{
 		Name: additionalSecretMount,
@@ -2080,6 +2108,7 @@ func (c *Cluster) generateLogicalBackupJob() (*batchv1.CronJob, error) {
 		logicalBackupContainer,
 		[]v1.Container{},
 		[]v1.Container{},
+		util.False(),
 		&[]v1.Toleration{},
 		nil,
 		nil,