From 556acc792b9a496827014b8ed6d1c82612dc3355 Mon Sep 17 00:00:00 2001
From: Victor Marmol <vmarmol@google.com>
Date: Thu, 26 Feb 2015 09:25:01 -0800
Subject: [PATCH] Adding ContainersPerPodCount metric.

This will let us know the composition of pods in clusters.
---
 pkg/kubelet/kubelet.go         |  5 +++++
 pkg/kubelet/metrics/metrics.go | 10 ++++++++--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/pkg/kubelet/kubelet.go b/pkg/kubelet/kubelet.go
index 5ca5b805b56..d918c6003c3 100644
--- a/pkg/kubelet/kubelet.go
+++ b/pkg/kubelet/kubelet.go
@@ -1306,6 +1306,11 @@ func (kl *Kubelet) SyncPods(pods []api.BoundPod, podSyncTypes map[types.UID]metr
 		kl.podWorkers.UpdatePod(pod, func() {
 			metrics.SyncPodLatency.WithLabelValues(podSyncTypes[pod.UID].String()).Observe(metrics.SinceInMicroseconds(start))
 		})
+
+		// Note the number of containers for new pods.
+		if val, ok := podSyncTypes[pod.UID]; ok && (val == metrics.SyncPodCreate) {
+			metrics.ContainersPerPodCount.Observe(float64(len(pod.Spec.Containers)))
+		}
 	}
 
 	// Stop the workers for no-longer existing pods.
diff --git a/pkg/kubelet/metrics/metrics.go b/pkg/kubelet/metrics/metrics.go
index 629bcd0086e..ee8e5bffd84 100644
--- a/pkg/kubelet/metrics/metrics.go
+++ b/pkg/kubelet/metrics/metrics.go
@@ -36,7 +36,13 @@ var (
 			Help:      "Image pull latency in microseconds.",
 		},
 	)
-	// TODO(vmarmol): Break down by number of containers in pod?
+	ContainersPerPodCount = prometheus.NewSummary(
+		prometheus.SummaryOpts{
+			Subsystem: kubeletSubsystem,
+			Name:      "containers_per_pod_count",
+			Help:      "The number of containers per pod.",
+		},
+	)
 	SyncPodLatency = prometheus.NewSummaryVec(
 		prometheus.SummaryOpts{
 			Subsystem: kubeletSubsystem,
@@ -52,7 +58,6 @@ var (
 			Help:      "Latency in microseconds to sync all pods.",
 		},
 	)
-	// TODO(vmarmol): Containers per pod
 	DockerOperationsLatency = prometheus.NewSummaryVec(
 		prometheus.SummaryOpts{
 			Subsystem: kubeletSubsystem,
@@ -73,6 +78,7 @@ func Register(containerCache dockertools.DockerCache) {
 		prometheus.MustRegister(SyncPodLatency)
 		prometheus.MustRegister(DockerOperationsLatency)
 		prometheus.MustRegister(SyncPodsLatency)
+		prometheus.MustRegister(ContainersPerPodCount)
 		prometheus.MustRegister(newPodAndContainerCollector(containerCache))
 	})
 }