diff --git a/op/reboot.go b/op/reboot.go
index 03817c8a..d870d3ae 100644
--- a/op/reboot.go
+++ b/op/reboot.go
@@ -568,6 +568,13 @@ func drainBackOff(ctx context.Context, inf cke.Infrastructure, entry *cke.Reboot
 		"name":      entry.Node,
 		log.FnError: err,
 	})
+	etcdEntry, err := inf.Storage().GetRebootsEntry(ctx, entry.Index)
+	if err != nil {
+		return err
+	}
+	if etcdEntry.Status == cke.RebootStatusCancelled {
+		return nil
+	}
 	entry.Status = cke.RebootStatusQueued
 	entry.LastTransitionTime = time.Now().Truncate(time.Second).UTC()
 	entry.DrainBackOffCount++
diff --git a/op/reboot_decide.go b/op/reboot_decide.go
index c72e6b88..6f8f388c 100644
--- a/op/reboot_decide.go
+++ b/op/reboot_decide.go
@@ -196,12 +196,10 @@ func ChooseDrainedNodes(c *cke.Cluster, apiServers map[string]bool, rqEntries []
 			return nil
 		}
 	}
-	if len(workerInProgress) >= maxConcurrentReboots {
-		return nil
-	} else if len(workerInProgress)+len(workerDrainable) <= maxConcurrentReboots {
-		return workerDrainable
+	if len(workerInProgress) < maxConcurrentReboots && len(workerDrainable) > 0 {
+		return workerDrainable[:1]
 	} else {
-		return workerDrainable[:maxConcurrentReboots-len(workerInProgress)]
+		return nil
 	}
 }
 
diff --git a/server/strategy.go b/server/strategy.go
index c02704e5..bc5e5c46 100644
--- a/server/strategy.go
+++ b/server/strategy.go
@@ -104,7 +104,7 @@ func DecideOps(c *cke.Cluster, cs *cke.ClusterStatus, constraints *cke.Constrain
 	}
 
 	// 11. Reboot nodes if reboot request has been arrived to the reboot queue, and the number of unreachable nodes is less than a threshold.
-	if ops, phaseReboot := rebootOps(c, constraints, rebootArgs, nf); phaseReboot {
+	if ops := rebootOps(c, constraints, rebootArgs, nf); len(ops) > 0 {
 		if !nf.EtcdIsGood() {
 			log.Warn("cannot reboot nodes because etcd cluster is not responding and in-sync", nil)
 			return nil, cke.PhaseRebootNodes
@@ -871,26 +871,33 @@ func repairOps(c *cke.Cluster, cs *cke.ClusterStatus, constraints *cke.Constrain
 	return ops, phaseRepair
 }
 
-func rebootOps(c *cke.Cluster, constraints *cke.Constraints, rebootArgs DecideOpsRebootArgs, nf *NodeFilter) (ops []cke.Operator, phaseReboot bool) {
+func rebootOps(c *cke.Cluster, constraints *cke.Constraints, rebootArgs DecideOpsRebootArgs, nf *NodeFilter) (ops []cke.Operator) {
 	if len(rebootArgs.RQEntries) == 0 {
-		return nil, false
+		return nil
 	}
 	if len(c.Reboot.RebootCommand) == 0 {
 		log.Warn("reboot command is not specified in the cluster configuration", nil)
-		return nil, false
+		return nil
 	}
 	if len(c.Reboot.BootCheckCommand) == 0 {
 		log.Warn("boot check command is not specified in the cluster configuration", nil)
-		return nil, false
+		return nil
 	}
 
 	if len(rebootArgs.RebootCancelled) > 0 {
-		phaseReboot = true
 		ops = append(ops, op.RebootCancelOp(rebootArgs.RebootCancelled))
-		return ops, phaseReboot
+	}
+	if len(rebootArgs.RebootDequeued) > 0 {
+		ops = append(ops, op.RebootDequeueOp(rebootArgs.RebootDequeued))
+	}
+	if len(ops) > 0 {
+		return ops
+	}
+
+	if len(rebootArgs.DrainCompleted) > 0 {
+		ops = append(ops, op.RebootRebootOp(nf.HealthyAPIServer(), rebootArgs.DrainCompleted, &c.Reboot))
 	}
 	if len(rebootArgs.NewlyDrained) > 0 {
-		phaseReboot = true
 		sshCheckNodes := make([]*cke.Node, 0, len(nf.cluster.Nodes))
 		for _, node := range nf.cluster.Nodes {
 			if !rebootProcessing(rebootArgs.RQEntries, node.Address) {
@@ -903,23 +910,11 @@ func rebootOps(c *cke.Cluster, constraints *cke.Constraints, rebootArgs DecideOp
 			ops = append(ops, op.RebootDrainStartOp(nf.HealthyAPIServer(), rebootArgs.NewlyDrained, &c.Reboot))
 		}
 	}
-	if len(rebootArgs.DrainCompleted) > 0 {
-		phaseReboot = true
-		ops = append(ops, op.RebootRebootOp(nf.HealthyAPIServer(), rebootArgs.DrainCompleted, &c.Reboot))
-	}
 	if len(rebootArgs.DrainTimedout) > 0 {
-		phaseReboot = true
 		ops = append(ops, op.RebootDrainTimeoutOp(rebootArgs.DrainTimedout))
 	}
-	if len(rebootArgs.RebootDequeued) > 0 {
-		phaseReboot = true
-		ops = append(ops, op.RebootDequeueOp(rebootArgs.RebootDequeued))
-	}
-	if len(ops) > 0 {
-		phaseReboot = true
-	}
 
-	return ops, phaseReboot
+	return ops
 }
 
 func rebootUncordonOp(cs *cke.ClusterStatus, rqEntries []*cke.RebootQueueEntry, nf *NodeFilter) cke.Operator {