From e3dca2b123cb9be641403a4b437c212c15987763 Mon Sep 17 00:00:00 2001
From: Marcin Wielgus <mwielgus@google.com>
Date: Wed, 18 May 2016 15:59:26 +0200
Subject: [PATCH] Cluster-autoscaler: Fast drain impl that doesn't talk to api
 server

---
 cluster-autoscaler/simulator/drain.go | 79 +++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 cluster-autoscaler/simulator/drain.go

diff --git a/cluster-autoscaler/simulator/drain.go b/cluster-autoscaler/simulator/drain.go
new file mode 100644
index 0000000000..01a3f7667a
--- /dev/null
+++ b/cluster-autoscaler/simulator/drain.go
@@ -0,0 +1,79 @@
+/*
+Copyright 2015 The Kubernetes Authors 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 simulator
+
+import (
+	"fmt"
+
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/controller"
+	"k8s.io/kubernetes/pkg/kubelet/types"
+	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/plugin/pkg/scheduler/schedulercache"
+)
+
+// FastGetPodsToMove returns a list of pods that should be moved elsewhere if the node
+// is drained. Raises error if there is an unreplicated pod and force option was not specified.
+// Based on kubectl drain code. It makes an assumption that RC, DS, Jobs and RS were deleted
+// along with their pods (no abandoned pods with dangling created-by annotation). Usefull for fast
+// checks.
+func FastGetPodsToMove(nodeInfo schedulercache.NodeInfo, force bool, decoder runtime.Decoder) ([]*api.Pod, error) {
+	pods := make([]*api.Pod, 0)
+	unreplicatedPodNames := []string{}
+	for _, pod := range nodeInfo.Pods() {
+		_, found := pod.ObjectMeta.Annotations[types.ConfigMirrorAnnotationKey]
+		if found {
+			// Skip mirror pod
+			continue
+		}
+		replicated := false
+		daemonsetPod := false
+
+		creatorRef, found := pod.ObjectMeta.Annotations[controller.CreatedByAnnotation]
+		if found {
+			var sr api.SerializedReference
+			if err := runtime.DecodeInto(decoder, []byte(creatorRef), &sr); err != nil {
+				return pods, err
+			}
+			if sr.Reference.Kind == "ReplicationController" {
+				replicated = true
+			} else if sr.Reference.Kind == "DaemonSet" {
+				daemonsetPod = true
+			} else if sr.Reference.Kind == "Job" {
+				replicated = true
+			} else if sr.Reference.Kind == "ReplicaSet" {
+				replicated = true
+			}
+		}
+
+		switch {
+		case daemonsetPod:
+			break
+		case !replicated:
+			unreplicatedPodNames = append(unreplicatedPodNames, pod.Name)
+			if force {
+				pods = append(pods, pod)
+			}
+		default:
+			pods = append(pods, pod)
+		}
+	}
+	if !force && len(unreplicatedPodNames) > 0 {
+		return []*api.Pod{}, fmt.Errorf("unreplicated pods present")
+	}
+	return pods, nil
+}