prefilter extension point implementation.

pkg/scheduler/framework/v1alpha1/framework.go

@@ -36,6 +36,7 @@ type framework struct {
 	waitingPods      *waitingPodsMap
 	plugins          map[string]Plugin // a map of initialized plugins. Plugin name:plugin instance.
 	queueSortPlugins []QueueSortPlugin
+	prefilterPlugins []PrefilterPlugin
 	reservePlugins   []ReservePlugin
 	prebindPlugins   []PrebindPlugin
 	postbindPlugins  []PostbindPlugin
@@ -85,6 +86,20 @@ func NewFramework(r Registry, plugins *config.Plugins, args []config.PluginConfi
 		f.plugins[name] = p
 	}
 
+	if plugins.PreFilter != nil {
+		for _, pf := range plugins.PreFilter.Enabled {
+			if pg, ok := f.plugins[pf.Name]; ok {
+				p, ok := pg.(PrefilterPlugin)
+				if !ok {
+					return nil, fmt.Errorf("plugin %v does not extend prefilter plugin", pf.Name)
+				}
+				f.prefilterPlugins = append(f.prefilterPlugins, p)
+			} else {
+				return nil, fmt.Errorf("prefilter plugin %v does not exist", pf.Name)
+			}
+		}
+	}
+
 	if plugins.Reserve != nil {
 		for _, r := range plugins.Reserve.Enabled {
 			if pg, ok := f.plugins[r.Name]; ok {
@@ -185,6 +200,28 @@ func (f *framework) QueueSortFunc() LessFunc {
 	return f.queueSortPlugins[0].Less
 }
 
+// RunPrefilterPlugins runs the set of configured prefilter plugins. It returns
+// *Status and its code is set to non-success if any of the plugins returns
+// anything but Success. If a non-success status is returned, then the scheduling
+// cycle is aborted.
+func (f *framework) RunPrefilterPlugins(
+	pc *PluginContext, pod *v1.Pod) *Status {
+	for _, pl := range f.prefilterPlugins {
+		status := pl.Prefilter(pc, pod)
+		if !status.IsSuccess() {
+			if status.Code() == Unschedulable {
+				msg := fmt.Sprintf("rejected by %v at prefilter: %v", pl.Name(), status.Message())
+				klog.V(4).Infof(msg)
+				return NewStatus(status.Code(), msg)
+			}
+			msg := fmt.Sprintf("error while running %v prefilter plugin for pod %v: %v", pl.Name(), pod.Name, status.Message())
+			klog.Error(msg)
+			return NewStatus(Error, msg)
+		}
+	}
+	return nil
+}
+
 // RunPrebindPlugins runs the set of configured prebind plugins. It returns a
 // failure (bool) if any of the plugins returns an error. It also returns an
 // error containing the rejection message or the error occurred in the plugin.

pkg/scheduler/framework/v1alpha1/interface.go

@@ -126,6 +126,15 @@ type QueueSortPlugin interface {
 	Less(*PodInfo, *PodInfo) bool
 }
 
+// PrefilterPlugin is an interface that must be implemented by "prefilter" plugins.
+// These plugins are called at the beginning of the scheduling cycle.
+type PrefilterPlugin interface {
+	Plugin
+	// Prefilter is called at the beginning of the scheduling cycle. All prefilter
+	// plugins must return success or the pod will be rejected.
+	Prefilter(pc *PluginContext, p *v1.Pod) *Status
+}
+
 // ReservePlugin is an interface for Reserve plugins. These plugins are called
 // at the reservation point. These are meant to update the state of the plugin.
 // This concept used to be called 'assume' in the original scheduler.
@@ -190,6 +199,12 @@ type Framework interface {
 	// QueueSortFunc returns the function to sort pods in scheduling queue
 	QueueSortFunc() LessFunc
 
+	// RunPrefilterPlugins runs the set of configured prefilter plugins. It returns
+	// *Status and its code is set to non-success if any of the plugins returns
+	// anything but Success. If a non-success status is returned, then the scheduling
+	// cycle is aborted.
+	RunPrefilterPlugins(pc *PluginContext, pod *v1.Pod) *Status
+
 	// RunPrebindPlugins runs the set of configured prebind plugins. It returns
 	// *Status and its code is set to non-success if any of the plugins returns
 	// anything but Success. If the Status code is "Unschedulable", it is