Make Prometheus cAdvisor metrics labels consistent

Prometheus requires that all metrics in the same family have the same labels, so we arrange to supply blank strings for missing labels See google/cadvisor#1704
cofyc · Sep 25, 2017 · 6b7f334 · 6b7f334
1 parent 2c2fe6e
commit 6b7f334
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Showing 2 changed files with 32 additions and 16 deletions.
diff --git a/pkg/kubelet/cadvisor/cadvisor_linux.go b/pkg/kubelet/cadvisor/cadvisor_linux.go
@@ -74,21 +74,29 @@ func init() {
 }
 
 func containerLabels(c *cadvisorapi.ContainerInfo) map[string]string {
-	set := map[string]string{metrics.LabelID: c.Name}
+	// Prometheus requires that all metrics in the same family have the same labels,
+	// so we arrange to supply blank strings for missing labels
+	var name, image, podName, namespace, containerName string
 	if len(c.Aliases) > 0 {
-		set[metrics.LabelName] = c.Aliases[0]
-	}
-	if image := c.Spec.Image; len(image) > 0 {
-		set[metrics.LabelImage] = image
+		name = c.Aliases[0]
 	}
+	image = c.Spec.Image
 	if v, ok := c.Spec.Labels[types.KubernetesPodNameLabel]; ok {
-		set["pod_name"] = v
+		podName = v
 	}
 	if v, ok := c.Spec.Labels[types.KubernetesPodNamespaceLabel]; ok {
-		set["namespace"] = v
+		namespace = v
 	}
 	if v, ok := c.Spec.Labels[types.KubernetesContainerNameLabel]; ok {
-		set["container_name"] = v
+		containerName = v
+	}
+	set := map[string]string{
+		metrics.LabelID:    c.Name,
+		metrics.LabelName:  name,
+		metrics.LabelImage: image,
+		"pod_name":         podName,
+		"namespace":        namespace,
+		"container_name":   containerName,
 	}
 	return set
 }

diff --git a/pkg/kubelet/server/server.go b/pkg/kubelet/server/server.go
@@ -816,21 +816,29 @@ func (a prometheusHostAdapter) GetMachineInfo() (*cadvisorapi.MachineInfo, error
 
 // containerPrometheusLabels maps cAdvisor labels to prometheus labels.
 func containerPrometheusLabels(c *cadvisorapi.ContainerInfo) map[string]string {
-	set := map[string]string{metrics.LabelID: c.Name}
+	// Prometheus requires that all metrics in the same family have the same labels,
+	// so we arrange to supply blank strings for missing labels
+	var name, image, podName, namespace, containerName string
 	if len(c.Aliases) > 0 {
-		set[metrics.LabelName] = c.Aliases[0]
-	}
-	if image := c.Spec.Image; len(image) > 0 {
-		set[metrics.LabelImage] = image
+		name = c.Aliases[0]
 	}
+	image = c.Spec.Image
 	if v, ok := c.Spec.Labels[kubelettypes.KubernetesPodNameLabel]; ok {
-		set["pod_name"] = v
+		podName = v
 	}
 	if v, ok := c.Spec.Labels[kubelettypes.KubernetesPodNamespaceLabel]; ok {
-		set["namespace"] = v
+		namespace = v
 	}
 	if v, ok := c.Spec.Labels[kubelettypes.KubernetesContainerNameLabel]; ok {
-		set["container_name"] = v
+		containerName = v
+	}
+	set := map[string]string{
+		metrics.LabelID:    c.Name,
+		metrics.LabelName:  name,
+		metrics.LabelImage: image,
+		"pod_name":         podName,
+		"namespace":        namespace,
+		"container_name":   containerName,
 	}
 	return set
 }