Running resource predicate on kubelet.

Added checking on kubelet if scheduled pods do not exceed resources. Related to #5207.

pkg/kubelet/kubelet.go

@@ -32,7 +32,6 @@ import (
 	"time"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/resource"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/validation"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/capabilities"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
@@ -47,6 +46,7 @@ import (
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/probe"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/scheduler"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/types"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
 	utilErrors "github.com/GoogleCloudPlatform/kubernetes/pkg/util/errors"
@@ -321,6 +321,9 @@ type Kubelet struct {
 
 	// Manager for images.
 	imageManager imageManager
+
+	// Cached MachineInfo returned by cadvisor.
+	machineInfo *cadvisorApi.MachineInfo
 }
 
 // getRootDir returns the full path to the directory under which kubelet can
@@ -1477,7 +1480,7 @@ func (kl *Kubelet) SyncPods(allPods []api.Pod, podSyncTypes map[types.UID]metric
 	kl.removeOrphanedStatuses(podFullNames)
 
 	// Filter out the rejected pod. They don't have running containers.
-	kl.handleHostPortConflicts(allPods)
+	kl.handleNotfittingPods(allPods)
 	var pods []api.Pod
 	for _, pod := range allPods {
 		status, ok := kl.getPodStatusFromCache(GetPodFullName(&pod))
@@ -1636,14 +1639,44 @@ func getHostPortConflicts(pods []api.Pod) []api.Pod {
 	return conflicts
 }
 
-// handleHostPortConflicts handles pods that conflict on Port.HostPort values.
-func (kl *Kubelet) handleHostPortConflicts(pods []api.Pod) {
+func (kl *Kubelet) getPodsExceedingCapacity(pods []api.Pod) []api.Pod {
+	info, err := kl.GetCachedMachineInfo()
+	if err != nil {
+		glog.Error("error getting machine info: %v", err)
+		return []api.Pod{}
+	}
+
+	// Respect the pod creation order when resolving conflicts.
+	sort.Sort(podsByCreationTime(pods))
+
+	capacity := CapacityFromMachineInfo(info)
+	return scheduler.GetPodsExceedingCapacity(pods, capacity)
+}
+
+// handleNotfittingPods handles pods that do not fit on the node.
+// Currently conflicts on Port.HostPort values and exceeding node capacity are handled.
+func (kl *Kubelet) handleNotfittingPods(pods []api.Pod) {
 	conflicts := getHostPortConflicts(pods)
+	conflictsMap := map[types.UID]bool{}
 	for _, pod := range conflicts {
 		kl.recorder.Eventf(&pod, "hostPortConflict", "Cannot start the pod due to host port conflict.")
 		kl.setPodStatusInCache(GetPodFullName(&pod), api.PodStatus{
 			Phase:   api.PodFailed,
 			Message: "Pod cannot be started due to host port conflict"})
+		conflictsMap[pod.UID] = true
+	}
+	remainingPods := []api.Pod{}
+	for _, pod := range pods {
+		if !conflictsMap[pod.UID] {
+			remainingPods = append(remainingPods, pod)
+		}
+	}
+	conflicts = kl.getPodsExceedingCapacity(remainingPods)
+	for _, pod := range conflicts {
+		kl.recorder.Eventf(&pod, "capacityExceeded", "Cannot start the pod due to exceeded capacity.")
+		kl.setPodStatusInCache(GetPodFullName(&pod), api.PodStatus{
+			Phase:   api.PodFailed,
+			Message: "Pod cannot be started due to exceeded capacity"})
 	}
 }
 
@@ -1867,20 +1900,13 @@ func (kl *Kubelet) tryUpdateNodeStatus() error {
 
 	// TODO: Post NotReady if we cannot get MachineInfo from cAdvisor. This needs to start
 	// cAdvisor locally, e.g. for test-cmd.sh, and in integration test.
-	info, err := kl.GetMachineInfo()
+	info, err := kl.GetCachedMachineInfo()
 	if err != nil {
 		glog.Error("error getting machine info: %v", err)
 	} else {
 		node.Status.NodeInfo.MachineID = info.MachineID
 		node.Status.NodeInfo.SystemUUID = info.SystemUUID
-		node.Spec.Capacity = api.ResourceList{
-			api.ResourceCPU: *resource.NewMilliQuantity(
-				int64(info.NumCores*1000),
-				resource.DecimalSI),
-			api.ResourceMemory: *resource.NewQuantity(
-				info.MemoryCapacity,
-				resource.BinarySI),
-		}
+		node.Spec.Capacity = CapacityFromMachineInfo(info)
 	}
 
 	newCondition := api.NodeCondition{
@@ -2155,6 +2181,14 @@ func (kl *Kubelet) GetRootInfo(req *cadvisorApi.ContainerInfoRequest) (*cadvisor
 	return kl.cadvisor.ContainerInfo("/", req)
 }
 
-func (kl *Kubelet) GetMachineInfo() (*cadvisorApi.MachineInfo, error) {
-	return kl.cadvisor.MachineInfo()
+// GetCachedMachineInfo assumes that the machine info can't change without a reboot
+func (kl *Kubelet) GetCachedMachineInfo() (*cadvisorApi.MachineInfo, error) {
+	if kl.machineInfo == nil {
+		info, err := kl.cadvisor.MachineInfo()
+		if err != nil {
+			return nil, err
+		}
+		kl.machineInfo = info
+	}
+	return kl.machineInfo, nil
 }

pkg/kubelet/kubelet_test.go

@@ -412,6 +412,7 @@ var emptyPodUIDs map[types.UID]metrics.SyncPodType
 
 func TestSyncPodsDoesNothing(t *testing.T) {
 	testKubelet := newTestKubelet(t)
+	testKubelet.fakeCadvisor.On("MachineInfo").Return(&cadvisorApi.MachineInfo{}, nil)
 	kubelet := testKubelet.kubelet
 	fakeDocker := testKubelet.fakeDocker
 	waitGroup := testKubelet.waitGroup
@@ -454,6 +455,7 @@ func TestSyncPodsDoesNothing(t *testing.T) {
 
 func TestSyncPodsWithTerminationLog(t *testing.T) {
 	testKubelet := newTestKubelet(t)
+	testKubelet.fakeCadvisor.On("MachineInfo").Return(&cadvisorApi.MachineInfo{}, nil)
 	kubelet := testKubelet.kubelet
 	fakeDocker := testKubelet.fakeDocker
 	waitGroup := testKubelet.waitGroup
@@ -506,6 +508,7 @@ func matchString(t *testing.T, pattern, str string) bool {
 
 func TestSyncPodsCreatesNetAndContainer(t *testing.T) {
 	testKubelet := newTestKubelet(t)
+	testKubelet.fakeCadvisor.On("MachineInfo").Return(&cadvisorApi.MachineInfo{}, nil)
 	kubelet := testKubelet.kubelet
 	fakeDocker := testKubelet.fakeDocker
 	waitGroup := testKubelet.waitGroup
@@ -557,6 +560,7 @@ func TestSyncPodsCreatesNetAndContainer(t *testing.T) {
 
 func TestSyncPodsCreatesNetAndContainerPullsImage(t *testing.T) {
 	testKubelet := newTestKubelet(t)
+	testKubelet.fakeCadvisor.On("MachineInfo").Return(&cadvisorApi.MachineInfo{}, nil)
 	kubelet := testKubelet.kubelet
 	fakeDocker := testKubelet.fakeDocker
 	waitGroup := testKubelet.waitGroup
@@ -604,6 +608,7 @@ func TestSyncPodsCreatesNetAndContainerPullsImage(t *testing.T) {
 
 func TestSyncPodsWithPodInfraCreatesContainer(t *testing.T) {
 	testKubelet := newTestKubelet(t)
+	testKubelet.fakeCadvisor.On("MachineInfo").Return(&cadvisorApi.MachineInfo{}, nil)
 	kubelet := testKubelet.kubelet
 	fakeDocker := testKubelet.fakeDocker
 	waitGroup := testKubelet.waitGroup
@@ -648,6 +653,7 @@ func TestSyncPodsWithPodInfraCreatesContainer(t *testing.T) {
 
 func TestSyncPodsWithPodInfraCreatesContainerCallsHandler(t *testing.T) {
 	testKubelet := newTestKubelet(t)
+	testKubelet.fakeCadvisor.On("MachineInfo").Return(&cadvisorApi.MachineInfo{}, nil)
 	kubelet := testKubelet.kubelet
 	fakeDocker := testKubelet.fakeDocker
 	waitGroup := testKubelet.waitGroup
@@ -708,6 +714,7 @@ func TestSyncPodsWithPodInfraCreatesContainerCallsHandler(t *testing.T) {
 
 func TestSyncPodsDeletesWithNoPodInfraContainer(t *testing.T) {
 	testKubelet := newTestKubelet(t)
+	testKubelet.fakeCadvisor.On("MachineInfo").Return(&cadvisorApi.MachineInfo{}, nil)
 	kubelet := testKubelet.kubelet
 	fakeDocker := testKubelet.fakeDocker
 	waitGroup := testKubelet.waitGroup
@@ -779,6 +786,7 @@ func TestSyncPodsDeletesWithNoPodInfraContainer(t *testing.T) {
 func TestSyncPodsDeletesWhenSourcesAreReady(t *testing.T) {
 	ready := false
 	testKubelet := newTestKubelet(t)
+	testKubelet.fakeCadvisor.On("MachineInfo").Return(&cadvisorApi.MachineInfo{}, nil)
 	kubelet := testKubelet.kubelet
 	fakeDocker := testKubelet.fakeDocker
 	kubelet.sourcesReady = func() bool { return ready }
@@ -823,6 +831,7 @@ func TestSyncPodsDeletesWhenSourcesAreReady(t *testing.T) {
 
 func TestSyncPodsDeletes(t *testing.T) {
 	testKubelet := newTestKubelet(t)
+	testKubelet.fakeCadvisor.On("MachineInfo").Return(&cadvisorApi.MachineInfo{}, nil)
 	kubelet := testKubelet.kubelet
 	fakeDocker := testKubelet.fakeDocker
 	fakeDocker.ContainerList = []docker.APIContainers{
@@ -1694,6 +1703,7 @@ func TestSyncPodEventHandlerFails(t *testing.T) {
 
 func TestSyncPodsWithPullPolicy(t *testing.T) {
 	testKubelet := newTestKubelet(t)
+	testKubelet.fakeCadvisor.On("MachineInfo").Return(&cadvisorApi.MachineInfo{}, nil)
 	kubelet := testKubelet.kubelet
 	fakeDocker := testKubelet.fakeDocker
 	waitGroup := testKubelet.waitGroup
@@ -2758,6 +2768,8 @@ func TestGetHostPortConflicts(t *testing.T) {
 func TestHandlePortConflicts(t *testing.T) {
 	testKubelet := newTestKubelet(t)
 	kl := testKubelet.kubelet
+	testKubelet.fakeCadvisor.On("MachineInfo").Return(&cadvisorApi.MachineInfo{}, nil)
+
 	spec := api.PodSpec{Containers: []api.Container{{Ports: []api.ContainerPort{{HostPort: 80}}}}}
 	pods := []api.Pod{
 		{
@@ -2783,7 +2795,7 @@ func TestHandlePortConflicts(t *testing.T) {
 	// The newer pod should be rejected.
 	conflictedPodName := GetPodFullName(&pods[0])
 
-	kl.handleHostPortConflicts(pods)
+	kl.handleNotfittingPods(pods)
 	if len(kl.podStatuses) != 1 {
 		t.Fatalf("expected length of status map to be 1. Got map %#v.", kl.podStatuses)
 	}
@@ -2807,15 +2819,76 @@ func TestHandlePortConflicts(t *testing.T) {
 	}
 }
 
+// Tests that we handle exceeded resources correctly by setting the failed status in status map.
+func TestHandleMemExceeded(t *testing.T) {
+	testKubelet := newTestKubelet(t)
+	kl := testKubelet.kubelet
+	testKubelet.fakeCadvisor.On("MachineInfo").Return(&cadvisorApi.MachineInfo{MemoryCapacity: 100}, nil)
+
+	spec := api.PodSpec{Containers: []api.Container{{Resources: api.ResourceRequirements{
+		Limits: api.ResourceList{
+			"memory": resource.MustParse("90"),
+		},
+	}}}}
+	pods := []api.Pod{
+		{
+			ObjectMeta: api.ObjectMeta{
+				UID:       "123456789",
+				Name:      "newpod",
+				Namespace: "foo",
+			},
+			Spec: spec,
+		},
+		{
+			ObjectMeta: api.ObjectMeta{
+				UID:       "987654321",
+				Name:      "oldpod",
+				Namespace: "foo",
+			},
+			Spec: spec,
+		},
+	}
+	// Make sure the Pods are in the reverse order of creation time.
+	pods[1].CreationTimestamp = util.NewTime(time.Now())
+	pods[0].CreationTimestamp = util.NewTime(time.Now().Add(1 * time.Second))
+	// The newer pod should be rejected.
+	notfittingPodName := GetPodFullName(&pods[0])
+
+	kl.handleNotfittingPods(pods)
+	if len(kl.podStatuses) != 1 {
+		t.Fatalf("expected length of status map to be 1. Got map %#v.", kl.podStatuses)
+	}
+	// Check pod status stored in the status map.
+	status, ok := kl.podStatuses[notfittingPodName]
+	if !ok {
+		t.Fatalf("status of pod %q is not found in the status map.", notfittingPodName)
+	}
+	if status.Phase != api.PodFailed {
+		t.Fatalf("expected pod status %q. Got %q.", api.PodFailed, status.Phase)
+	}
+
+	// Check if we can retrieve the pod status from GetPodStatus().
+	kl.pods = pods
+	status, err := kl.GetPodStatus(notfittingPodName, "")
+	if err != nil {
+		t.Fatalf("unable to retrieve pod status for pod %q: #v.", notfittingPodName, err)
+	}
+	if status.Phase != api.PodFailed {
+		t.Fatalf("expected pod status %q. Got %q.", api.PodFailed, status.Phase)
+	}
+}
+
 func TestPurgingObsoleteStatusMapEntries(t *testing.T) {
 	testKubelet := newTestKubelet(t)
+	testKubelet.fakeCadvisor.On("MachineInfo").Return(&cadvisorApi.MachineInfo{}, nil)
+
 	kl := testKubelet.kubelet
 	pods := []api.Pod{
 		{Spec: api.PodSpec{Containers: []api.Container{{Ports: []api.ContainerPort{{HostPort: 80}}}}}},
 		{Spec: api.PodSpec{Containers: []api.Container{{Ports: []api.ContainerPort{{HostPort: 80}}}}}},
 	}
 	// Run once to populate the status map.
-	kl.handleHostPortConflicts(pods)
+	kl.handleNotfittingPods(pods)
 	if len(kl.podStatuses) != 1 {
 		t.Fatalf("expected length of status map to be 1. Got map %#v.", kl.podStatuses)
 	}
@@ -3064,6 +3137,7 @@ func TestCreateMirrorPod(t *testing.T) {
 
 func TestDeleteOrphanedMirrorPods(t *testing.T) {
 	testKubelet := newTestKubelet(t)
+	testKubelet.fakeCadvisor.On("MachineInfo").Return(&cadvisorApi.MachineInfo{}, nil)
 	kl := testKubelet.kubelet
 	manager := testKubelet.fakeMirrorManager
 	orphanedPodNames := []string{"pod1_ns", "pod2_ns"}

pkg/kubelet/runonce.go

@@ -55,7 +55,7 @@ func (kl *Kubelet) runOnce(pods []api.Pod, retryDelay time.Duration) (results []
 	if kl.dockerPuller == nil {
 		kl.dockerPuller = dockertools.NewDockerPuller(kl.dockerClient, kl.pullQPS, kl.pullBurst)
 	}
-	kl.handleHostPortConflicts(pods)
+	kl.handleNotfittingPods(pods)
 
 	ch := make(chan RunPodResult)
 	for i := range pods {

pkg/kubelet/runonce_test.go

@@ -24,8 +24,10 @@ import (
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/client/record"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet/cadvisor"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet/dockertools"
 	docker "github.com/fsouza/go-dockerclient"
+	cadvisorApi "github.com/google/cadvisor/info/v1"
 )
 
 type listContainersResult struct {
@@ -68,10 +70,14 @@ func (d *testDocker) InspectContainer(id string) (*docker.Container, error) {
 }
 
 func TestRunOnce(t *testing.T) {
+	cadvisor := &cadvisor.Mock{}
+	cadvisor.On("MachineInfo").Return(&cadvisorApi.MachineInfo{}, nil)
 	kb := &Kubelet{
 		rootDirectory: "/tmp/kubelet",
 		recorder:      &record.FakeRecorder{},
+		cadvisor:      cadvisor,
 	}
+
 	if err := kb.setupDataDirs(); err != nil {
 		t.Errorf("Failed to init data dirs: %v", err)
 	}

pkg/kubelet/server.go

@@ -33,7 +33,6 @@ import (
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/latest"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/resource"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/healthz"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/httplog"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
@@ -50,7 +49,6 @@ import (
 type Server struct {
 	host HostInterface
 	mux  *http.ServeMux
-	machineInfo *cadvisorApi.MachineInfo
 }
 
 type TLSOptions struct {
@@ -84,7 +82,7 @@ type HostInterface interface {
 	GetContainerInfo(podFullName string, uid types.UID, containerName string, req *cadvisorApi.ContainerInfoRequest) (*cadvisorApi.ContainerInfo, error)
 	GetRootInfo(req *cadvisorApi.ContainerInfoRequest) (*cadvisorApi.ContainerInfo, error)
 	GetDockerVersion() ([]uint, error)
-	GetMachineInfo() (*cadvisorApi.MachineInfo, error)
+	GetCachedMachineInfo() (*cadvisorApi.MachineInfo, error)
 	GetPods() ([]api.Pod, util.StringSet)
 	GetPodByName(namespace, name string) (*api.Pod, bool)
 	GetPodStatus(name string, uid types.UID) (api.PodStatus, error)
@@ -329,33 +327,14 @@ func (s *Server) handleLogs(w http.ResponseWriter, req *http.Request) {
 	s.host.ServeLogs(w, req)
 }
 
-// getCachedMachineInfo assumes that the machine info can't change without a reboot
-func (s *Server) getCachedMachineInfo() (*cadvisorApi.MachineInfo, error) {
-	if s.machineInfo == nil {
-		info, err := s.host.GetMachineInfo()
-		if err != nil {
-			return nil, err
-		}
-		s.machineInfo = info
-	}
-	return s.machineInfo, nil
-}
-
 // handleNodeInfoVersioned handles node info requests against the Kubelet.
 func (s *Server) handleNodeInfoVersioned(w http.ResponseWriter, req *http.Request) {
-	info, err := s.getCachedMachineInfo()
+	info, err := s.host.GetCachedMachineInfo()
 	if err != nil {
 		s.error(w, err)
 		return
 	}
-	capacity := api.ResourceList{
-		api.ResourceCPU: *resource.NewMilliQuantity(
-			int64(info.NumCores*1000),
-			resource.DecimalSI),
-		api.ResourceMemory: *resource.NewQuantity(
-			info.MemoryCapacity,
-			resource.BinarySI),
-	}
+	capacity := CapacityFromMachineInfo(info)
 	data, err := json.Marshal(api.NodeInfo{
 		Capacity: capacity,
 		NodeSystemInfo: api.NodeSystemInfo{
@@ -363,6 +342,7 @@ func (s *Server) handleNodeInfoVersioned(w http.ResponseWriter, req *http.Reques
 			SystemUUID: info.SystemUUID,
 		},
 	})
+
 	if err != nil {
 		s.error(w, err)
 		return
@@ -373,7 +353,7 @@ func (s *Server) handleNodeInfoVersioned(w http.ResponseWriter, req *http.Reques
 
 // handleSpec handles spec requests against the Kubelet.
 func (s *Server) handleSpec(w http.ResponseWriter, req *http.Request) {
-	info, err := s.getCachedMachineInfo()
+	info, err := s.host.GetCachedMachineInfo()
 	if err != nil {
 		s.error(w, err)
 		return

pkg/kubelet/server_test.go

@@ -76,7 +76,7 @@ func (fk *fakeKubelet) GetDockerVersion() ([]uint, error) {
 	return fk.dockerVersionFunc()
 }
 
-func (fk *fakeKubelet) GetMachineInfo() (*cadvisorApi.MachineInfo, error) {
+func (fk *fakeKubelet) GetCachedMachineInfo() (*cadvisorApi.MachineInfo, error) {
 	return fk.machineInfoFunc()
 }
 

pkg/kubelet/util.go

@@ -17,10 +17,13 @@ limitations under the License.
 package kubelet
 
 import (
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/resource"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/capabilities"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/client/record"
 	"github.com/golang/glog"
+	cadvisorApi "github.com/google/cadvisor/info/v1"
 )
 
 // TODO: move this into pkg/capabilities
@@ -40,3 +43,15 @@ func SetupEventSending(client *client.Client, hostname string) {
 	glog.Infof("Sending events to api server.")
 	record.StartRecording(client.Events(""))
 }
+
+func CapacityFromMachineInfo(info *cadvisorApi.MachineInfo) api.ResourceList {
+	c := api.ResourceList{
+		api.ResourceCPU: *resource.NewMilliQuantity(
+			int64(info.NumCores*1000),
+			resource.DecimalSI),
+		api.ResourceMemory: *resource.NewQuantity(
+			info.MemoryCapacity,
+			resource.BinarySI),
+	}
+	return c
+}

pkg/scheduler/predicates.go

@@ -22,7 +22,6 @@ import (
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
-	"github.com/golang/glog"
 )
 
 type NodeInfo interface {
@@ -102,6 +101,28 @@ func getResourceRequest(pod *api.Pod) resourceRequest {
 	return result
 }
 
+func GetPodsExceedingCapacity(pods []api.Pod, capacity api.ResourceList) []api.Pod {
+	exceedingPods := []api.Pod{}
+	totalMilliCPU := capacity.Cpu().MilliValue()
+	totalMemory := capacity.Memory().Value()
+	milliCPURequested := int64(0)
+	memoryRequested := int64(0)
+	for ix := range pods {
+		podRequest := getResourceRequest(&pods[ix])
+		fitsCPU := totalMilliCPU == 0 || (totalMilliCPU-milliCPURequested) >= podRequest.milliCPU
+		fitsMemory := totalMemory == 0 || (totalMemory-memoryRequested) >= podRequest.memory
+		if !fitsCPU || !fitsMemory {
+			// the pod doesn't fit
+			exceedingPods = append(exceedingPods, pods[ix])
+		} else {
+			// the pod fits
+			milliCPURequested += podRequest.milliCPU
+			memoryRequested += podRequest.memory
+		}
+	}
+	return exceedingPods
+}
+
 // PodFitsResources calculates fit based on requested, rather than used resources
 func (r *ResourceFit) PodFitsResources(pod api.Pod, existingPods []api.Pod, node string) (bool, error) {
 	podRequest := getResourceRequest(&pod)
@@ -113,22 +134,13 @@ func (r *ResourceFit) PodFitsResources(pod api.Pod, existingPods []api.Pod, node
 	if err != nil {
 		return false, err
 	}
-	milliCPURequested := int64(0)
-	memoryRequested := int64(0)
-	for ix := range existingPods {
-		existingRequest := getResourceRequest(&existingPods[ix])
-		milliCPURequested += existingRequest.milliCPU
-		memoryRequested += existingRequest.memory
+	pods := []api.Pod{}
+	copy(pods, existingPods)
+	pods = append(existingPods, pod)
+	if len(GetPodsExceedingCapacity(pods, info.Spec.Capacity)) > 0 {
+		return false, nil
 	}
-
-	totalMilliCPU := info.Spec.Capacity.Cpu().MilliValue()
-	totalMemory := info.Spec.Capacity.Memory().Value()
-
-	fitsCPU := totalMilliCPU == 0 || (totalMilliCPU-milliCPURequested) >= podRequest.milliCPU
-	fitsMemory := totalMemory == 0 || (totalMemory-memoryRequested) >= podRequest.memory
-	glog.V(3).Infof("Calculated fit: cpu: %v, memory %v", fitsCPU, fitsMemory)
-
-	return fitsCPU && fitsMemory, nil
+	return true, nil
 }
 
 func NewResourceFitPredicate(info NodeInfo) FitPredicate {