From 862937bf1c7975d3f54ae47a2958e47f2c50150f Mon Sep 17 00:00:00 2001
From: Daein Park <bysnupy@hotmail.com>
Date: Wed, 16 Jun 2021 21:25:52 +0900
Subject: [PATCH] Add a flag to enable "Capacity" instead of "Allocatable" for
 an actual node memory total usage.

If "Allocatable" is used to a node total memory size, under high memory pressure or pre-reserved memory value is bigger, the "MEMORY%" can be bigger than 100%.
For suppressing the confusing, add a option to show node real memory usage based on "Capacity".
* Reference: https://github.com/kubernetes/kubernetes/issues/86499
---
 staging/src/k8s.io/kubectl/pkg/cmd/top/top_node.go | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/staging/src/k8s.io/kubectl/pkg/cmd/top/top_node.go b/staging/src/k8s.io/kubectl/pkg/cmd/top/top_node.go
index 2f530d78f51..667fa30c728 100644
--- a/staging/src/k8s.io/kubectl/pkg/cmd/top/top_node.go
+++ b/staging/src/k8s.io/kubectl/pkg/cmd/top/top_node.go
@@ -43,6 +43,7 @@ type TopNodeOptions struct {
 	SortBy             string
 	NoHeaders          bool
 	UseProtocolBuffers bool
+	ShowCapacity       bool
 
 	NodeClient      corev1client.CoreV1Interface
 	Printer         *metricsutil.TopCmdPrinter
@@ -91,6 +92,7 @@ func NewCmdTopNode(f cmdutil.Factory, o *TopNodeOptions, streams genericclioptio
 	cmd.Flags().StringVar(&o.SortBy, "sort-by", o.SortBy, "If non-empty, sort nodes list using specified field. The field can be either 'cpu' or 'memory'.")
 	cmd.Flags().BoolVar(&o.NoHeaders, "no-headers", o.NoHeaders, "If present, print output without headers")
 	cmd.Flags().BoolVar(&o.UseProtocolBuffers, "use-protocol-buffers", o.UseProtocolBuffers, "Enables using protocol-buffers to access Metrics API.")
+	cmd.Flags().BoolVar(&o.ShowCapacity, "show-capacity", o.ShowCapacity, "Print node resources based on Capacity instead of Allocatable(default) of the nodes.")
 
 	return cmd
 }
@@ -186,13 +188,17 @@ func (o TopNodeOptions) RunTopNode() error {
 		nodes = append(nodes, nodeList.Items...)
 	}
 
-	allocatable := make(map[string]v1.ResourceList)
+	availableResources := make(map[string]v1.ResourceList)
 
 	for _, n := range nodes {
-		allocatable[n.Name] = n.Status.Allocatable
+		if !o.ShowCapacity {
+			availableResources[n.Name] = n.Status.Allocatable
+		} else {
+			availableResources[n.Name] = n.Status.Capacity
+		}
 	}
 
-	return o.Printer.PrintNodeMetrics(metrics.Items, allocatable, o.NoHeaders, o.SortBy)
+	return o.Printer.PrintNodeMetrics(metrics.Items, availableResources, o.NoHeaders, o.SortBy)
 }
 
 func getNodeMetricsFromMetricsAPI(metricsClient metricsclientset.Interface, resourceName string, selector labels.Selector) (*metricsapi.NodeMetricsList, error) {