From 11888db742c042af607fe084493d30cc2833742c Mon Sep 17 00:00:00 2001
From: Joe Talerico aka rook <joe.talerico@gmail.com>
Date: Thu, 9 Jan 2025 15:10:54 -0500
Subject: [PATCH] Label hint

If the user wants to provide hints to help schedule the client and
server on specific nodes, they can add `netperf=true` label to the nodes
they want tested.

Signed-off-by: Joe Talerico aka rook <joe.talerico@gmail.com>
---
 README.md             | 10 ++++++++++
 pkg/k8s/kubernetes.go | 31 +++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/README.md b/README.md
index 6fa1d79..c7bf5dd 100644
--- a/README.md
+++ b/README.md
@@ -35,6 +35,16 @@ $ cd k8s-netperf
 $ make container-build
 ```
 
+## Label nodes
+k8s-netperf will make the best decision it can to schedule the client and server in your cluster. However,
+you can provide hints to ensure the client and server will always land on specific nodes.
+
+To do this, apply a label to the nodes you want the client and server running
+
+```shell
+$ oc label nodes node-name netperf=true
+```
+
 ## Running with Pods
 Ensure your `kubeconfig` is properly set to the cluster you would like to run `k8s-netperf` against.
 
diff --git a/pkg/k8s/kubernetes.go b/pkg/k8s/kubernetes.go
index 36e953a..2649318 100644
--- a/pkg/k8s/kubernetes.go
+++ b/pkg/k8s/kubernetes.go
@@ -342,6 +342,21 @@ func BuildSUT(client *kubernetes.Clientset, s *config.PerfScenarios) error {
 				RequiredDuringSchedulingIgnoredDuringExecution: workerNodeSelectorExpression,
 			}
 		}
+	} else {
+		affinity := corev1.NodeAffinity{
+			PreferredDuringSchedulingIgnoredDuringExecution: []corev1.PreferredSchedulingTerm{
+				{
+					Weight: 100,
+					Preference: corev1.NodeSelectorTerm{
+						MatchExpressions: []corev1.NodeSelectorRequirement{
+							{Key: "netperf", Operator: corev1.NodeSelectorOpIn, Values: []string{"true"}},
+						},
+					},
+				},
+			},
+		}
+		cdpAcross.NodeAffinity = affinity
+		cdpHostAcross.NodeAffinity = affinity
 	}
 
 	if ncount > 1 {
@@ -427,6 +442,21 @@ func BuildSUT(client *kubernetes.Clientset, s *config.PerfScenarios) error {
 		}
 		sdp.NodeAffinity = affinity
 		sdpHost.NodeAffinity = affinity
+	} else {
+		affinity := corev1.NodeAffinity{
+			PreferredDuringSchedulingIgnoredDuringExecution: []corev1.PreferredSchedulingTerm{
+				{
+					Weight: 100,
+					Preference: corev1.NodeSelectorTerm{
+						MatchExpressions: []corev1.NodeSelectorRequirement{
+							{Key: "netperf", Operator: corev1.NodeSelectorOpIn, Values: []string{"true"}},
+						},
+					},
+				},
+			},
+		}
+		sdp.NodeAffinity = affinity
+		sdpHost.NodeAffinity = affinity
 	}
 	if ncount > 1 {
 		antiAffinity := corev1.PodAntiAffinity{
@@ -583,6 +613,7 @@ func zoneNodeSelectorExpression(zone string) []corev1.PreferredSchedulingTerm {
 			Preference: corev1.NodeSelectorTerm{
 				MatchExpressions: []corev1.NodeSelectorRequirement{
 					{Key: "topology.kubernetes.io/zone", Operator: corev1.NodeSelectorOpIn, Values: []string{zone}},
+					{Key: "netperf", Operator: corev1.NodeSelectorOpIn, Values: []string{"true"}},
 				},
 			},
 		},