chaos: add initial commit for chaos monkeys

pkg/chaos/chaos.go

@@ -0,0 +1,62 @@
+// Copyright 2016 The kube-etcd-controller Authors
+//
+// 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 chaos
+
+import (
+	"context"
+	"math/rand"
+
+	"github.com/Sirupsen/logrus"
+	"golang.org/x/time/rate"
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/client/unversioned"
+	"k8s.io/kubernetes/pkg/labels"
+)
+
+// Monkeys knows how to crush pods and nodes.
+type Monkeys struct {
+	k8s *unversioned.Client
+}
+
+// TODO: respect context in k8s operations.
+func (m *Monkeys) CrushPods(ctx context.Context, ns string, ls labels.Selector, killRate int) {
+	limiter := rate.NewLimiter(rate.Limit(killRate), killRate)
+	for {
+		err := limiter.Wait(ctx)
+		if err != nil { // user cancellation
+			logrus.Infof("crushPods is cancelled for selector %v by the user: %v", ls.String(), err)
+			return
+		}
+
+		pods, err := m.k8s.Pods(ns).List(api.ListOptions{LabelSelector: ls})
+		if err != nil {
+			logrus.Errorf("failed to list pods for selector %v: %v", ls.String(), err)
+			continue
+		}
+		if len(pods.Items) == 0 {
+			logrus.Infof("no pods to kill for selector %v", ls.String())
+			continue
+		}
+
+		// todo: kill multiple pods in one round?
+		tokill := pods.Items[rand.Intn(len(pods.Items))].Name
+		err = m.k8s.Pods(ns).Delete(tokill, nil)
+		if err != nil {
+			logrus.Errorf("failed to kill pod %v: %v", tokill, err)
+			continue
+		}
+		logrus.Infof("killed pod %v for selector %v", tokill, ls.String())
+	}
+}