Ensure CPUManager TopologyHints are regenerated after kubelet restart

This patch also includes test to make sure the newly added logic works
as expected.

pkg/kubelet/cm/cpumanager/policy_static.go

@@ -320,6 +320,23 @@ func (p *staticPolicy) GetTopologyHints(s state.State, pod v1.Pod, container v1.
 		return nil
 	}
 
+	// Short circuit to regenerate the same hints if there are already
+	// guaranteed CPUs allocated to the Container. This might happen after a
+	// kubelet restart, for example.
+	containerID, _ := findContainerIDByName(&pod.Status, container.Name)
+	if allocated, exists := s.GetCPUSet(containerID); exists {
+		if allocated.Size() != requested {
+			klog.Errorf("[cpumanager] CPUs already allocated to (pod %v, container %v) with different number than request: requested: %d, allocated: %d", string(pod.UID), container.Name, requested, allocated.Size())
+			return map[string][]topologymanager.TopologyHint{
+				string(v1.ResourceCPU): {},
+			}
+		}
+		klog.Infof("[cpumanager] Regenerating TopologyHints for CPUs already allocated to (pod %v, container %v)", string(pod.UID), container.Name)
+		return map[string][]topologymanager.TopologyHint{
+			string(v1.ResourceCPU): p.generateCPUTopologyHints(allocated, requested),
+		}
+	}
+
 	// Get a list of available CPUs.
 	available := p.assignableCPUs(s)
 

pkg/kubelet/cm/cpumanager/policy_static_test.go

@@ -213,6 +213,20 @@ func TestStaticPolicyAdd(t *testing.T) {
 			expCPUAlloc:     true,
 			expCSet:         cpuset.NewCPUSet(1, 5),
 		},
+		{
+			description:     "GuPodMultipleCores, SingleSocketHT, ExpectSameAllocation",
+			topo:            topoSingleSocketHT,
+			numReservedCPUs: 1,
+			containerID:     "fakeID3",
+			stAssignments: state.ContainerCPUAssignments{
+				"fakeID3": cpuset.NewCPUSet(2, 3, 6, 7),
+			},
+			stDefaultCPUSet: cpuset.NewCPUSet(0, 1, 4, 5),
+			pod:             makePod("4000m", "4000m"),
+			expErr:          nil,
+			expCPUAlloc:     true,
+			expCSet:         cpuset.NewCPUSet(2, 3, 6, 7),
+		},
 		{
 			description:     "GuPodMultipleCores, DualSocketHT, ExpectAllocOneSocket",
 			topo:            topoDualSocketHT,

pkg/kubelet/cm/cpumanager/topology_hints_test.go

@@ -23,6 +23,7 @@ import (
 
 	cadvisorapi "github.com/google/cadvisor/info/v1"
 	v1 "k8s.io/api/core/v1"
+	"k8s.io/kubernetes/pkg/kubelet/cm/cpumanager/state"
 	"k8s.io/kubernetes/pkg/kubelet/cm/cpumanager/topology"
 	"k8s.io/kubernetes/pkg/kubelet/cm/cpuset"
 	"k8s.io/kubernetes/pkg/kubelet/cm/topologymanager"
@@ -72,6 +73,7 @@ func TestGetTopologyHints(t *testing.T) {
 		name          string
 		pod           v1.Pod
 		container     v1.Container
+		assignments   state.ContainerCPUAssignments
 		defaultCPUSet cpuset.CPUSet
 		expectedHints []topologymanager.TopologyHint
 	}{
@@ -142,6 +144,86 @@ func TestGetTopologyHints(t *testing.T) {
 				},
 			},
 		},
+		{
+			name:          "Request more CPUs than available",
+			pod:           *testPod2,
+			container:     *testContainer2,
+			defaultCPUSet: cpuset.NewCPUSet(0, 1, 2, 3),
+			expectedHints: nil,
+		},
+		{
+			name:      "Regenerate Single-Node NUMA Hints if already allocated 1/2",
+			pod:       *testPod1,
+			container: *testContainer1,
+			assignments: state.ContainerCPUAssignments{
+				"": cpuset.NewCPUSet(0, 6),
+			},
+			defaultCPUSet: cpuset.NewCPUSet(),
+			expectedHints: []topologymanager.TopologyHint{
+				{
+					NUMANodeAffinity: firstSocketMask,
+					Preferred:        true,
+				},
+				{
+					NUMANodeAffinity: crossSocketMask,
+					Preferred:        false,
+				},
+			},
+		},
+		{
+			name:      "Regenerate Single-Node NUMA Hints if already allocated 1/2",
+			pod:       *testPod1,
+			container: *testContainer1,
+			assignments: state.ContainerCPUAssignments{
+				"": cpuset.NewCPUSet(3, 9),
+			},
+			defaultCPUSet: cpuset.NewCPUSet(),
+			expectedHints: []topologymanager.TopologyHint{
+				{
+					NUMANodeAffinity: secondSocketMask,
+					Preferred:        true,
+				},
+				{
+					NUMANodeAffinity: crossSocketMask,
+					Preferred:        false,
+				},
+			},
+		},
+		{
+			name:      "Regenerate Cross-NUMA Hints if already allocated",
+			pod:       *testPod4,
+			container: *testContainer4,
+			assignments: state.ContainerCPUAssignments{
+				"": cpuset.NewCPUSet(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10),
+			},
+			defaultCPUSet: cpuset.NewCPUSet(),
+			expectedHints: []topologymanager.TopologyHint{
+				{
+					NUMANodeAffinity: crossSocketMask,
+					Preferred:        true,
+				},
+			},
+		},
+		{
+			name:      "Requested less than already allocated",
+			pod:       *testPod1,
+			container: *testContainer1,
+			assignments: state.ContainerCPUAssignments{
+				"": cpuset.NewCPUSet(0, 6, 3, 9),
+			},
+			defaultCPUSet: cpuset.NewCPUSet(),
+			expectedHints: []topologymanager.TopologyHint{},
+		},
+		{
+			name:      "Requested more than already allocated",
+			pod:       *testPod4,
+			container: *testContainer4,
+			assignments: state.ContainerCPUAssignments{
+				"": cpuset.NewCPUSet(0, 6, 3, 9),
+			},
+			defaultCPUSet: cpuset.NewCPUSet(),
+			expectedHints: []topologymanager.TopologyHint{},
+		},
 	}
 	for _, tc := range tcases {
 		topology, _ := topology.Discover(&machineInfo, numaNodeInfo)
@@ -151,9 +233,13 @@ func TestGetTopologyHints(t *testing.T) {
 				topology: topology,
 			},
 			state: &mockState{
+				assignments:   tc.assignments,
 				defaultCPUSet: tc.defaultCPUSet,
 			},
-			topology: topology,
+			topology:          topology,
+			activePods:        func() []*v1.Pod { return nil },
+			podStatusProvider: mockPodStatusProvider{},
+			sourcesReady:      &sourcesReadyStub{},
 		}
 
 		hints := m.GetTopologyHints(tc.pod, tc.container)[string(v1.ResourceCPU)]