K8SPG-737: expose /pgdata mountpoint for node_exporter

https://perconadev.atlassian.net/browse/K8SPG-737

Author: pooknull

e2e-tests/tests/monitoring-pmm3/08-check-mountpoint-expose.yaml

@@ -0,0 +1,20 @@
+apiVersion: kuttl.dev/v1beta1
+kind: TestStep
+commands:
+  - script: |-
+      set -o errexit
+      set -o xtrace
+
+      source ../../functions
+
+      series_fetched=$(curl --insecure -G "https://admin:admin@$(get_service_ip monitoring-service)/prometheus/api/v1/query_range" \
+           --data-urlencode "query=node_filesystem_free_bytes{mountpoint=\"/pgdata\"}" \
+           --data-urlencode "start=$(($(date +%s) - 300))" \
+           --data-urlencode "end=$(date +%s)" \
+           --data-urlencode "step=5s" | jq -r '.stats.seriesFetched')
+
+      if [[ $series_fetched == 0 ]]; then 
+        echo "seriesFetched is 0"
+        exit 1
+      fi
+    timeout: 360

e2e-tests/tests/monitoring/08-check-mountpoint-expose.yaml

@@ -0,0 +1,20 @@
+apiVersion: kuttl.dev/v1beta1
+kind: TestStep
+commands:
+  - script: |-
+      set -o errexit
+      set -o xtrace
+
+      source ../../functions
+
+      series_fetched=$(curl --insecure -G "https://admin:admin@$(get_service_ip monitoring-service)/prometheus/api/v1/query_range" \
+           --data-urlencode "query=node_filesystem_free_bytes{mountpoint=\"/pgdata\"}" \
+           --data-urlencode "start=$(($(date +%s) - 300))" \
+           --data-urlencode "end=$(date +%s)" \
+           --data-urlencode "step=5s" | jq -r '.stats.seriesFetched')
+
+      if [[ $series_fetched == 0 ]]; then 
+        echo "seriesFetched is 0"
+        exit 1
+      fi
+    timeout: 360

…ng/08-deleted-from-server-inventory.yaml …ng/09-deleted-from-server-inventory.yamle2e-tests/tests/monitoring/08-deleted-from-server-inventory.yaml renamed to e2e-tests/tests/monitoring/09-deleted-from-server-inventory.yaml e2e-tests/tests/monitoring/08-deleted-from-server-inventory.yaml renamed to e2e-tests/tests/monitoring/09-deleted-from-server-inventory.yaml

@@ -1351,7 +1351,7 @@ func generateInstanceStatefulSetIntent(_ context.Context,
 	// ShareProcessNamespace makes Kubernetes' pause process PID 1 and lets
 	// containers see each other's processes.
 	// - https://docs.k8s.io/tasks/configure-pod-container/share-process-namespace/
-	sts.Spec.Template.Spec.ShareProcessNamespace = initialize.Bool(true)
+	sts.Spec.Template.Spec.ShareProcessNamespace = initialize.Bool(false) // K8SPG-737: should be false
 
 	// Patroni calls the Kubernetes API and pgBackRest may interact with a cloud
 	// storage provider. Use the instance ServiceAccount and automatically mount

internal/controller/postgrescluster/instance.go

@@ -7,6 +7,7 @@ import (
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/util/intstr"
 
+	"github.com/percona/percona-postgresql-operator/internal/postgres"
 	v2 "github.com/percona/percona-postgresql-operator/pkg/apis/pgv2.percona.com/v2"
 )
 
@@ -80,6 +81,11 @@ func sidecarContainerV2(pgc *v2.PerconaPGCluster) corev1.Container {
 				MountPath: "/pgconf/tls",
 				ReadOnly:  true,
 			},
+			{
+				Name:      postgres.DataVolumeMount().Name,
+				MountPath: postgres.DataVolumeMount().MountPath,
+				ReadOnly:  true,
+			},
 		},
 		Env: []corev1.EnvVar{
 			{
@@ -288,6 +294,11 @@ func sidecarContainerV3(pgc *v2.PerconaPGCluster) corev1.Container {
 				MountPath: "/pgconf/tls",
 				ReadOnly:  true,
 			},
+			{
+				Name:      postgres.DataVolumeMount().Name,
+				MountPath: postgres.DataVolumeMount().MountPath,
+				ReadOnly:  true,
+			},
 		},
 		Env: []corev1.EnvVar{
 			{