[NodeKiller] Add randomization on node killing

clusterloader2/pkg/chaos/nodes.go

@@ -86,6 +86,7 @@ func (k *NodeKiller) pickNodes() ([]v1.Node, error) {
 	for i := range prometheusPods {
 		if prometheusPods[i].Spec.NodeName != "" {
 			nodesHasPrometheusPod.Insert(prometheusPods[i].Spec.NodeName)
+			klog.Infof("%s: Node %s removed from killing. Runs pod %s", k, prometheusPods[i].Spec.NodeName, prometheusPods[i].Name)
 		}
 	}
 
@@ -98,11 +99,17 @@ func (k *NodeKiller) pickNodes() ([]v1.Node, error) {
 	rand.Shuffle(len(nodes), func(i, j int) {
 		nodes[i], nodes[j] = nodes[j], nodes[i]
 	})
-	numNodes := int(k.config.FailureRate * float64(len(nodes)))
-	if len(nodes) > numNodes {
-		return nodes[:numNodes], nil
+	expectedNodesToFail := k.config.FailureRate * float64(len(nodes))
+	nodesToFail := nodes[:0]
+	klog.Infof("%s: %d nodes available, estimating to select %f nodes", k, len(nodes), expectedNodesToFail)
+	for _, node := range nodes {
+		if rand.Float64() < k.config.FailureRate {
+			klog.Infof("%s: Node %q schedule for failure", k, node.Name)
+			nodesToFail = append(nodesToFail, node)
+		}
 	}
-	return nodes, nil
+	klog.Infof("%s: Total %d nodes scheduled for failure", k, len(nodesToFail))
+	return nodesToFail, nil
 }
 
 func (k *NodeKiller) kill(nodes []v1.Node) {