From aaa0d12cc7429c4772268f4d41ffb172f89ba665 Mon Sep 17 00:00:00 2001
From: Pavithra Ramesh <pavithrar@google.com>
Date: Fri, 17 Apr 2020 10:36:21 -0700
Subject: [PATCH] Add back anti-affinity to kube-dns pods.

This change also updates to the latest kube-dns images. The
anti-affinity change was previously rolled back in https://github.com/kubernetes/kubernetes/pull/59357
Adding this back as there have been imrpovements in scheduler
performance since.
---
 cluster/addons/dns/kube-dns/kube-dns.yaml.base | 11 +++++++++++
 cluster/addons/dns/kube-dns/kube-dns.yaml.in   | 11 +++++++++++
 cluster/addons/dns/kube-dns/kube-dns.yaml.sed  | 11 +++++++++++
 3 files changed, 33 insertions(+)

diff --git a/cluster/addons/dns/kube-dns/kube-dns.yaml.base b/cluster/addons/dns/kube-dns/kube-dns.yaml.base
index 5e6a938a859..ab1fd09bfb8 100644
--- a/cluster/addons/dns/kube-dns/kube-dns.yaml.base
+++ b/cluster/addons/dns/kube-dns/kube-dns.yaml.base
@@ -90,6 +90,17 @@ spec:
       securityContext:
         supplementalGroups: [ 65534 ]
         fsGroup: 65534
+      affinity:
+        podAntiAffinity:
+          preferredDuringSchedulingIgnoredDuringExecution:
+          - weight: 100
+            podAffinityTerm:
+              labelSelector:
+                matchExpressions:
+                  - key: k8s-app
+                    operator: In
+                    values: ["kube-dns"]
+              topologyKey: kubernetes.io/hostname
       tolerations:
       - key: "CriticalAddonsOnly"
         operator: "Exists"
diff --git a/cluster/addons/dns/kube-dns/kube-dns.yaml.in b/cluster/addons/dns/kube-dns/kube-dns.yaml.in
index ff592801bdf..daf50c54a0e 100644
--- a/cluster/addons/dns/kube-dns/kube-dns.yaml.in
+++ b/cluster/addons/dns/kube-dns/kube-dns.yaml.in
@@ -90,6 +90,17 @@ spec:
       securityContext:
         supplementalGroups: [ 65534 ]
         fsGroup: 65534
+      affinity:
+        podAntiAffinity:
+          preferredDuringSchedulingIgnoredDuringExecution:
+          - weight: 100
+            podAffinityTerm:
+              labelSelector:
+                matchExpressions:
+                  - key: k8s-app
+                    operator: In
+                    values: ["kube-dns"]
+              topologyKey: kubernetes.io/hostname
       tolerations:
       - key: "CriticalAddonsOnly"
         operator: "Exists"
diff --git a/cluster/addons/dns/kube-dns/kube-dns.yaml.sed b/cluster/addons/dns/kube-dns/kube-dns.yaml.sed
index 9c8360f526c..9f944c9a1e7 100644
--- a/cluster/addons/dns/kube-dns/kube-dns.yaml.sed
+++ b/cluster/addons/dns/kube-dns/kube-dns.yaml.sed
@@ -90,6 +90,17 @@ spec:
       securityContext:
         supplementalGroups: [ 65534 ]
         fsGroup: 65534
+      affinity:
+        podAntiAffinity:
+          preferredDuringSchedulingIgnoredDuringExecution:
+          - weight: 100
+            podAffinityTerm:
+              labelSelector:
+                matchExpressions:
+                  - key: k8s-app
+                    operator: In
+                    values: ["kube-dns"]
+              topologyKey: kubernetes.io/hostname
       tolerations:
       - key: "CriticalAddonsOnly"
         operator: "Exists"