From 00a30509d6f08d9ce1d2ee1680fdbc684a41e8af Mon Sep 17 00:00:00 2001
From: Avesh Agarwal <avagarwa@redhat.com>
Date: Mon, 31 Jul 2017 01:13:49 -0400
Subject: [PATCH] Implement ready node lister.

---
 pkg/rescheduler/node/node.go | 78 ++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 pkg/rescheduler/node/node.go

diff --git a/pkg/rescheduler/node/node.go b/pkg/rescheduler/node/node.go
new file mode 100644
index 000000000..5bfe16a8c
--- /dev/null
+++ b/pkg/rescheduler/node/node.go
@@ -0,0 +1,78 @@
+/*
+Copyright 2017 The Kubernetes 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 node
+
+import (
+	"time"
+
+	"k8s.io/api/v1"
+	"k8s.io/apimachinery/pkg/fields"
+	corelisters "k8s.io/client-go/listers/core/v1"
+	"k8s.io/client-go/tools/cache"
+	"k8s.io/kubernetes/pkg/client/clientset_generated/clientset"
+)
+
+// ReadyNodes returns ready nodes irrespective of whether they are
+// schedulable or not.
+func ReadyNodes(client clientset.Interface, stopChannel <-chan struct{}) ([]*v1.Node, error) {
+	nodes, err := nodeLister(client, stopChannel).List(labels.Everything())
+	if err != nil {
+		return []*v1.Node{}, err
+	}
+	readyNodes := make([]*v1.Node, 0, len(nodes))
+	for _, node := range nodes {
+		if IsReady(node) {
+			readyNodes = append(readyNodes, node)
+		}
+	}
+	return readyNodes, nil
+}
+
+func nodeLister(client clientset.Interface, stopChannel <-chan struct{}) corelisters.NodeLister {
+	listWatcher := cache.NewListWatchFromClient(client.CoreV1().RESTClient(), "nodes", v1.NamespaceAll, fields.Everything())
+	store := cache.NewIndexer(cache.MetaNamespaceKeyFunc, cache.Indexers{cache.NamespaceIndex: cache.MetaNamespaceIndexFunc})
+	nodeLister := corelisters.NewNodeLister(store)
+	reflector := cache.NewReflector(listWatcher, &v1.Node{}, store, time.Hour)
+	reflector.RunUntil(stopChannel)
+	return nodeLister
+}
+
+func IsReady(node *v1.Node) bool {
+	for i := range node.Status.Conditions {
+		cond := &node.Status.Conditions[i]
+		// We consider the node for scheduling only when its:
+		// - NodeReady condition status is ConditionTrue,
+		// - NodeOutOfDisk condition status is ConditionFalse,
+		// - NodeNetworkUnavailable condition status is ConditionFalse.
+		if cond.Type == v1.NodeReady && cond.Status != v1.ConditionTrue {
+			glog.V(4).Infof("Ignoring node %v with %v condition status %v", node.Name, cond.Type, cond.Status)
+			return false
+		} /*else if cond.Type == v1.NodeOutOfDisk && cond.Status != v1.ConditionFalse {
+			glog.V(4).Infof("Ignoring node %v with %v condition status %v", node.Name, cond.Type, cond.Status)
+			return false
+		} else if cond.Type == v1.NodeNetworkUnavailable && cond.Status != v1.ConditionFalse {
+			glog.V(4).Infof("Ignoring node %v with %v condition status %v", node.Name, cond.Type, cond.Status)
+			return false
+		}*/
+	}
+	// Ignore nodes that are marked unschedulable
+	/*if node.Spec.Unschedulable {
+		glog.V(4).Infof("Ignoring node %v since it is unschedulable", node.Name)
+		return false
+	}*/
+	return true
+}