resources: run metrics-exporter in same pod as smbd

When config option metrics-exporter-mode is "enabled", run the
metrics-exporter container along-side smbd, within the same pod. Both
containers share the same volumes.

Image of smbmetrics exporter is developed within a separate repository:

  https://github.com/samba-in-kubernetes/smbmetrics

Signed-off-by: Shachar Sharon <[email protected]>

Author: synarete

internal/resources/deployments.go

@@ -51,7 +51,7 @@ func buildDeployment(cfg *conf.OperatorConfig,
 			Template: corev1.PodTemplateSpec{
 				ObjectMeta: metav1.ObjectMeta{
 					Labels:      labels,
-					Annotations: annotationsForSmbPod(cfg.SmbdContainerName),
+					Annotations: annotationsForSmbPod(cfg),
 				},
 				Spec: buildPodSpec(planner, cfg, pvcName),
 			},
@@ -86,9 +86,20 @@ func labelValue(s ...string) string {
 	return out
 }
 
-func annotationsForSmbPod(name string) map[string]string {
-	return map[string]string{
+func annotationsForSmbPod(cfg *conf.OperatorConfig) map[string]string {
+	name := cfg.SmbdContainerName
+	annotations := map[string]string{
 		"kubectl.kubernetes.io/default-logs-container": name,
 		"kubectl.kubernetes.io/default-container":      name,
 	}
+	if withMetricsExporter(cfg) {
+		for k, v := range annotationsForSmbMetricsPod() {
+			annotations[k] = v
+		}
+	}
+	return annotations
+}
+
+func withMetricsExporter(cfg *conf.OperatorConfig) bool {
+	return strings.ToLower(cfg.MetricsExporterMode) == "enabled"
 }

internal/resources/metrics.go

@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: Apache-2.0
+
+package resources
+
+import (
+	"strconv"
+
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/util/intstr"
+)
+
+var (
+	// defaultMetricsPort is the default port used to export prometheus metrics
+	defaultMetricsPort = int(8080)
+	// defaultMetricsPath is the default HTTP path to export prometheus metrics
+	defaultMetricsPath = "/metrics"
+)
+
+// annotationsForSmbMetricsPod returns the default annotation which are
+// required on the pod which executes the smbmetrics container, in order for
+// Prometheus to scrape it.
+func annotationsForSmbMetricsPod() map[string]string {
+	return map[string]string{
+		"prometheus.io/scrape": "true",
+		"prometheus.io/port":   strconv.Itoa(defaultMetricsPort),
+		"prometheus.io/path":   defaultMetricsPath,
+	}
+}
+
+// buildSmbMetricsContainer returns the appropriate Container definition for
+// smbmetrics exporter.
+func buildSmbMetricsContainer(image string,
+	volmnts []corev1.VolumeMount) corev1.Container {
+	portnum := defaultMetricsPort
+	return corev1.Container{
+		Image:   image,
+		Name:    "samba-metrics",
+		Command: []string{"/bin/smbmetrics"},
+		Ports: []corev1.ContainerPort{{
+			ContainerPort: int32(portnum),
+			Name:          "smbmetrics",
+		}},
+		VolumeMounts: volmnts,
+		ReadinessProbe: &corev1.Probe{
+			Handler: corev1.Handler{
+				TCPSocket: &corev1.TCPSocketAction{
+					Port: intstr.FromInt(portnum),
+				},
+			},
+		},
+		LivenessProbe: &corev1.Probe{
+			Handler: corev1.Handler{
+				TCPSocket: &corev1.TCPSocketAction{
+					Port: intstr.FromInt(portnum),
+				},
+			},
+		},
+	}
+}

internal/resources/pods.go

@@ -90,10 +90,9 @@ func buildADPodSpec(
 		},
 	)
 
-	containers := []corev1.Container{
-		buildSmbdCtr(planner, podEnv, smbdVols),
-		buildWinbinddCtr(planner, podEnv, smbServerVols),
-	}
+	containers := buildSmbdCtrs(planner, podEnv, smbdVols)
+	containers = append(containers,
+		buildWinbinddCtr(planner, podEnv, smbServerVols))
 
 	if planner.DNSRegister() != pln.DNSRegisterNever {
 		watchVol := svcWatchVolumeAndMount(
@@ -146,9 +145,7 @@ func buildUserPodSpec(
 	podEnv := defaultPodEnv(planner)
 	podSpec := defaultPodSpec(planner)
 	podSpec.Volumes = getVolumes(vols)
-	podSpec.Containers = []corev1.Container{
-		buildSmbdCtr(planner, podEnv, vols),
-	}
+	podSpec.Containers = buildSmbdCtrs(planner, podEnv, vols)
 	return podSpec
 }
 
@@ -256,7 +253,7 @@ func buildClusteredUserPodSpec(
 	// smbd
 	containers = append(
 		containers,
-		buildSmbdCtr(planner, podEnv, volumes))
+		buildSmbdCtrs(planner, podEnv, volumes)...)
 
 	podSpec := defaultPodSpec(planner)
 	podSpec.Volumes = getVolumes(volumes)
@@ -398,7 +395,7 @@ func buildClusteredADPodSpec(
 	// smbd
 	containers = append(
 		containers,
-		buildSmbdCtr(planner, podEnv, volumes))
+		buildSmbdCtrs(planner, podEnv, volumes)...)
 
 	// dns-register containers
 	if planner.DNSRegister() != pln.DNSRegisterNever {
@@ -423,6 +420,19 @@ func buildClusteredADPodSpec(
 	return podSpec
 }
 
+func buildSmbdCtrs(
+	planner *pln.Planner,
+	env []corev1.EnvVar,
+	vols []volMount) []corev1.Container {
+	// ---
+	ctrs := []corev1.Container{}
+	ctrs = append(ctrs, buildSmbdCtr(planner, env, vols))
+	if withMetricsExporter(planner.GlobalConfig) {
+		ctrs = append(ctrs, buildSmbdMetricsCtr(planner, vols))
+	}
+	return ctrs
+}
+
 func buildSmbdCtr(
 	planner *pln.Planner,
 	env []corev1.EnvVar,
@@ -457,6 +467,14 @@ func buildSmbdCtr(
 	}
 }
 
+func buildSmbdMetricsCtr(
+	planner *pln.Planner,
+	vols []volMount) corev1.Container {
+	// ---
+	return buildSmbMetricsContainer(
+		planner.GlobalConfig.SmbdMetricsContainerImage, getMounts(vols))
+}
+
 func buildWinbinddCtr(
 	planner *pln.Planner,
 	env []corev1.EnvVar,

internal/resources/statefulsets.go

@@ -47,7 +47,7 @@ func buildStatefulSet(
 			Template: corev1.PodTemplateSpec{
 				ObjectMeta: metav1.ObjectMeta{
 					Labels:      labels,
-					Annotations: annotationsForSmbPod(planner.GlobalConfig.SmbdContainerName),
+					Annotations: annotationsForSmbPod(planner.GlobalConfig),
 				},
 				Spec: podSpec,
 			},