Begin scheduler plugin

plugin/cmd/scheduler/scheduler.go

@@ -0,0 +1,141 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"flag"
+	"math/rand"
+	"time"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/client/cache"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
+	algorithm "github.com/GoogleCloudPlatform/kubernetes/pkg/scheduler"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+	verflag "github.com/GoogleCloudPlatform/kubernetes/pkg/version/flag"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/watch"
+	"github.com/GoogleCloudPlatform/kubernetes/plugin/pkg/scheduler"
+)
+
+var (
+	master = flag.String("master", "", "The address of the Kubernetes API server")
+)
+
+// storeToMinionLister turns a store into a minion lister. The store must contain (only) minions.
+type storeToMinionLister struct {
+	s cache.Store
+}
+
+func (s storeToMinionLister) List() (machines []string, err error) {
+	for _, m := range s.s.List() {
+		machines = append(machines, m.(*api.Minion).ID)
+	}
+	return machines, nil
+}
+
+// storeToPodLister turns a store into a pod lister. The store must contain (only) pods.
+type storeToPodLister struct {
+	s cache.Store
+}
+
+func (s storeToPodLister) ListPods(selector labels.Selector) (pods []api.Pod, err error) {
+	for _, m := range s.s.List() {
+		pod := m.(*api.Pod)
+		if selector.Matches(labels.Set(pod.Labels)) {
+			pods = append(pods, *pod)
+		}
+	}
+	return pods, nil
+}
+
+type binder struct {
+	kubeClient *client.Client
+}
+
+// Bind just does a POST binding RPC.
+func (b binder) Bind(binding *api.Binding) error {
+	return b.kubeClient.Post().Path("bindings").Body(binding).Do().Error()
+}
+
+func main() {
+	flag.Parse()
+	util.InitLogs()
+	defer util.FlushLogs()
+
+	verflag.PrintAndExitIfRequested()
+
+	// This function is long because we inject all the dependencies into scheduler here.
+
+	// TODO: security story for plugins!
+	kubeClient := client.New("http://"+*master, nil)
+
+	// Watch and queue pods that need scheduling.
+	podQueue := cache.NewFIFO()
+	cache.NewReflector(func(resourceVersion uint64) (watch.Interface, error) {
+		// This query will only find pods with no assigned host.
+		return kubeClient.
+			Get().
+			Path("pods").
+			Path("watch").
+			SelectorParam("fields", labels.Set{"DesiredState.Host": ""}.AsSelector()).
+			UintParam("resourceVersion", resourceVersion).
+			Watch()
+	}, &api.Pod{}, podQueue).Run()
+
+	// Watch and cache all running pods. Scheduler needs to find all pods
+	// so it knows where it's safe to place a pod. Cache this locally.
+	podCache := cache.NewStore()
+	cache.NewReflector(func(resourceVersion uint64) (watch.Interface, error) {
+		// This query will only find pods that do have an assigned host.
+		return kubeClient.
+			Get().
+			Path("pods").
+			Path("watch").
+			ParseSelectorParam("fields", "DesiredState.Host!=").
+			UintParam("resourceVersion", resourceVersion).
+			Watch()
+	}, &api.Pod{}, podCache).Run()
+
+	// Watch minions.
+	// Minions may be listed frequently, so provide a local up-to-date cache.
+	minionCache := cache.NewStore()
+	cache.NewReflector(func(resourceVersion uint64) (watch.Interface, error) {
+		// This query will only find pods that do have an assigned host.
+		return kubeClient.
+			Get().
+			Path("minions").
+			Path("watch").
+			UintParam("resourceVersion", resourceVersion).
+			Watch()
+	}, &api.Minion{}, minionCache).Run()
+
+	r := rand.New(rand.NewSource(time.Now().UnixNano()))
+	algo := algorithm.NewRandomFitScheduler(
+		storeToPodLister{podCache}, r)
+
+	s := scheduler.New(&scheduler.Config{
+		MinionLister: storeToMinionLister{minionCache},
+		Algorithm:    algo,
+		NextPod:      func() *api.Pod { return podQueue.Pop().(*api.Pod) },
+		Binder:       binder{kubeClient},
+	})
+
+	s.Run()
+
+	select {}
+}