rbd: support NoDiskConflicts scheduler predicates

Signed-off-by: Huamin Chen <hchen@redhat.com>

plugin/pkg/scheduler/algorithm/predicates/predicates.go

@@ -76,13 +76,30 @@ func isVolumeConflict(volume api.Volume, pod *api.Pod) bool {
 			}
 		}
 	}
+	if volume.RBD != nil {
+		mon := volume.RBD.CephMonitors
+		pool := volume.RBD.RBDPool
+		image := volume.RBD.RBDImage
+
+		manifest := &(pod.Spec)
+		for ix := range manifest.Volumes {
+			if manifest.Volumes[ix].RBD != nil {
+				mon_m := manifest.Volumes[ix].RBD.CephMonitors
+				pool_m := manifest.Volumes[ix].RBD.RBDPool
+				image_m := manifest.Volumes[ix].RBD.RBDImage
+				if haveSame(mon, mon_m) && pool_m == pool && image_m == image {
+					return true
+				}
+			}
+		}
+	}
 	return false
 }
 
 // NoDiskConflict evaluates if a pod can fit due to the volumes it requests, and those that
 // are already mounted. Some times of volumes are mounted onto node machines.  For now, these mounts
 // are exclusive so if there is already a volume mounted on that node, another pod can't schedule
-// there. This is GCE and Amazon EBS specific for now.
+// there. This is GCE, Amazon EBS, and Ceph RBD specific for now.
 // TODO: migrate this into some per-volume specific code?
 func NoDiskConflict(pod *api.Pod, existingPods []*api.Pod, node string) (bool, error) {
 	manifest := &(pod.Spec)
@@ -412,3 +429,15 @@ func MapPodsToMachines(lister algorithm.PodLister) (map[string][]*api.Pod, error
 	}
 	return machineToPods, nil
 }
+
+// search two arrays and return true if they have at least one common element; return false otherwise
+func haveSame(a1, a2 []string) bool {
+	for _, val1 := range a1 {
+		for _, val2 := range a2 {
+			if val1 == val2 {
+				return true
+			}
+		}
+	}
+	return false
+}

plugin/pkg/scheduler/algorithm/predicates/predicates_test.go

@@ -435,6 +435,61 @@ func TestAWSDiskConflicts(t *testing.T) {
 	}
 }
 
+func TestRBDDiskConflicts(t *testing.T) {
+	volState := api.PodSpec{
+		Volumes: []api.Volume{
+			{
+				VolumeSource: api.VolumeSource{
+					RBD: &api.RBDVolumeSource{
+						CephMonitors: []string{"a", "b"},
+						RBDPool:      "foo",
+						RBDImage:     "bar",
+						FSType:       "ext4",
+					},
+				},
+			},
+		},
+	}
+	volState2 := api.PodSpec{
+		Volumes: []api.Volume{
+			{
+				VolumeSource: api.VolumeSource{
+					RBD: &api.RBDVolumeSource{
+						CephMonitors: []string{"c", "d"},
+						RBDPool:      "foo",
+						RBDImage:     "bar",
+						FSType:       "ext4",
+					},
+				},
+			},
+		},
+	}
+	tests := []struct {
+		pod          *api.Pod
+		existingPods []*api.Pod
+		isOk         bool
+		test         string
+	}{
+		{&api.Pod{}, []*api.Pod{}, true, "nothing"},
+		{&api.Pod{}, []*api.Pod{{Spec: volState}}, true, "one state"},
+		{&api.Pod{Spec: volState}, []*api.Pod{{Spec: volState}}, false, "same state"},
+		{&api.Pod{Spec: volState2}, []*api.Pod{{Spec: volState}}, true, "different state"},
+	}
+
+	for _, test := range tests {
+		ok, err := NoDiskConflict(test.pod, test.existingPods, "machine")
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if test.isOk && !ok {
+			t.Errorf("expected ok, got none.  %v %v %s", test.pod, test.existingPods, test.test)
+		}
+		if !test.isOk && ok {
+			t.Errorf("expected no ok, got one.  %v %v %s", test.pod, test.existingPods, test.test)
+		}
+	}
+}
+
 func TestPodFitsSelector(t *testing.T) {
 	tests := []struct {
 		pod    *api.Pod