implement inter pod topological affinity and anti-affinity

plugin/pkg/scheduler/algorithm/priorities/util/non_zero.go

@@ -16,7 +16,12 @@ limitations under the License.
 
 package util
 
-import "k8s.io/kubernetes/pkg/api"
+import (
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/api/unversioned"
+	"k8s.io/kubernetes/pkg/labels"
+	"k8s.io/kubernetes/pkg/util/sets"
+)
 
 // For each of these resources, a pod that doesn't request the resource explicitly
 // will be treated as having requested the amount indicated below, for the purpose
@@ -48,3 +53,83 @@ func GetNonzeroRequests(requests *api.ResourceList) (int64, int64) {
 	}
 	return outMilliCPU, outMemory
 }
+
+// FilterPodsByNameSpaces filters the pods based the given list of namespaces,
+// empty set of namespaces means all namespaces.
+func FilterPodsByNameSpaces(names sets.String, pods []*api.Pod) []*api.Pod {
+	if len(pods) == 0 || len(names) == 0 {
+		return pods
+	}
+	result := []*api.Pod{}
+	for _, pod := range pods {
+		if names.Has(pod.Namespace) {
+			result = append(result, pod)
+		}
+	}
+	return result
+}
+
+// GetNamespacesFromPodAffinityTerm returns a set of names
+// according to the namespaces indicated in podAffinityTerm.
+// if the NameSpaces is nil considers the given pod's namespace
+// if the Namespaces is empty list then considers all the namespaces
+func GetNamespacesFromPodAffinityTerm(pod *api.Pod, podAffinityTerm api.PodAffinityTerm) sets.String {
+	names := sets.String{}
+	if podAffinityTerm.Namespaces == nil {
+		names.Insert(pod.Namespace)
+	} else if len(podAffinityTerm.Namespaces) != 0 {
+		names.Insert(podAffinityTerm.Namespaces...)
+	}
+	return names
+}
+
+// NodesHaveSameTopologyKeyInternal checks if nodeA and nodeB have same label value with given topologyKey as label key.
+func NodesHaveSameTopologyKeyInternal(nodeA, nodeB *api.Node, topologyKey string) bool {
+	return nodeA.Labels != nil && nodeB.Labels != nil && len(nodeA.Labels[topologyKey]) > 0 && nodeA.Labels[topologyKey] == nodeB.Labels[topologyKey]
+}
+
+type Topologies struct {
+	DefaultKeys []string
+}
+
+// NodesHaveSameTopologyKey checks if nodeA and nodeB have same label value with given topologyKey as label key.
+// If the topologyKey is nil/empty, check if the two nodes have any of the default topologyKeys, and have same corresponding label value.
+func (tps *Topologies) NodesHaveSameTopologyKey(nodeA *api.Node, nodeB *api.Node, topologyKey string) bool {
+	if len(topologyKey) == 0 {
+		// assumes this is allowed only for PreferredDuringScheduling pod anti-affinity (ensured by api/validation)
+		for _, defaultKey := range tps.DefaultKeys {
+			if NodesHaveSameTopologyKeyInternal(nodeA, nodeB, defaultKey) {
+				return true
+			}
+		}
+		return false
+	} else {
+		return NodesHaveSameTopologyKeyInternal(nodeA, nodeB, topologyKey)
+	}
+}
+
+type getNodeFunc func(*api.Pod) (*api.Node, error)
+
+// CheckIfPodMatchPodAffinityTerm checks if podB's affinity request is compatible with podA
+func (tps *Topologies) CheckIfPodMatchPodAffinityTerm(podA *api.Pod, podB *api.Pod, podBAffinityTerm api.PodAffinityTerm, getNodeA, getNodeB getNodeFunc) (bool, error) {
+	names := GetNamespacesFromPodAffinityTerm(podB, podBAffinityTerm)
+	if len(names) != 0 && !names.Has(podA.Namespace) {
+		return false, nil
+	}
+
+	labelSelector, err := unversioned.LabelSelectorAsSelector(podBAffinityTerm.LabelSelector)
+	if err != nil || !labelSelector.Matches(labels.Set(podA.Labels)) {
+		return false, err
+	}
+
+	podANode, err := getNodeA(podA)
+	if err != nil {
+		return false, err
+	}
+	podBNode, err := getNodeB(podB)
+	if err != nil {
+		return false, err
+	}
+
+	return tps.NodesHaveSameTopologyKey(podANode, podBNode, podBAffinityTerm.TopologyKey), nil
+}