rbd: support NoDiskConflicts scheduler predicates

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

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