From e3dcd96301ee01ded95da9ae3a3091c99a3238ec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20de=20Saint=20Martin?=
<cedric@desaintmartin.fr>
Date: Thu, 9 Aug 2018 17:42:53 +0200
Subject: [PATCH] kubedns & kubedns-autoscaler: Stick to master nodes. (#2909)
* kubedns & kubedns-autoscaler: Stick to master nodes.
- Tolerate only master nodes and not any NoSchedule taint
- Pods are on different nodes
- Pods are required to be on a master node.
* kubedns: use soft nodeAffinity.
Prefer to be on a master node, don't require.
* coredns: Stick to (different) master nodes.
- Pods are on different nodes
- Pods are preferred to be on a master node.
---
.../templates/coredns-deployment.yml.j2 | 16 ++++++++++++++
.../templates/kubedns-autoscaler.yml.j2 | 19 ++++++++++++++++-
.../ansible/templates/kubedns-deploy.yml.j2 | 21 +++++++++++++++++--
3 files changed, 53 insertions(+), 3 deletions(-)
diff --git a/roles/kubernetes-apps/ansible/templates/coredns-deployment.yml.j2 b/roles/kubernetes-apps/ansible/templates/coredns-deployment.yml.j2
index 5cba6f1f0..dc1f51937 100644
--- a/roles/kubernetes-apps/ansible/templates/coredns-deployment.yml.j2
+++ b/roles/kubernetes-apps/ansible/templates/coredns-deployment.yml.j2
@@ -34,6 +34,22 @@ spec:
effect: NoSchedule
- key: "CriticalAddonsOnly"
operator: "Exists"
+ affinity:
+ podAntiAffinity:
+ requiredDuringSchedulingIgnoredDuringExecution:
+ - topologyKey: "kubernetes.io/hostname"
+ labelSelector:
+ matchLabels:
+ k8s-app: coredns{{ coredns_ordinal_suffix | default('') }}
+ nodeAffinity:
+ preferredDuringSchedulingIgnoredDuringExecution:
+ - weight: 100
+ preference:
+ matchExpressions:
+ - key: node-role.kubernetes.io/master
+ operator: In
+ values:
+ - "true"
containers:
- name: coredns
image: "{{ coredns_image_repo }}:{{ coredns_image_tag }}"
diff --git a/roles/kubernetes-apps/ansible/templates/kubedns-autoscaler.yml.j2 b/roles/kubernetes-apps/ansible/templates/kubedns-autoscaler.yml.j2
index d7c30eceb..73ae3a01a 100644
--- a/roles/kubernetes-apps/ansible/templates/kubedns-autoscaler.yml.j2
+++ b/roles/kubernetes-apps/ansible/templates/kubedns-autoscaler.yml.j2
@@ -30,7 +30,24 @@ spec:
spec:
tolerations:
- effect: NoSchedule
- operator: Exists
+ operator: Equal
+ key: node-role.kubernetes.io/master
+ affinity:
+ podAntiAffinity:
+ requiredDuringSchedulingIgnoredDuringExecution:
+ - topologyKey: "kubernetes.io/hostname"
+ labelSelector:
+ matchLabels:
+ k8s-app: kubedns-autoscaler
+ nodeAffinity:
+ preferredDuringSchedulingIgnoredDuringExecution:
+ - weight: 100
+ preference:
+ matchExpressions:
+ - key: node-role.kubernetes.io/master
+ operator: In
+ values:
+ - "true"
containers:
- name: autoscaler
image: "{{ kubednsautoscaler_image_repo }}:{{ kubednsautoscaler_image_tag }}"
diff --git a/roles/kubernetes-apps/ansible/templates/kubedns-deploy.yml.j2 b/roles/kubernetes-apps/ansible/templates/kubedns-deploy.yml.j2
index cfce65f0e..bb040780f 100644
--- a/roles/kubernetes-apps/ansible/templates/kubedns-deploy.yml.j2
+++ b/roles/kubernetes-apps/ansible/templates/kubedns-deploy.yml.j2
@@ -30,8 +30,25 @@ spec:
tolerations:
- key: "CriticalAddonsOnly"
operator: "Exists"
- - effect: NoSchedule
- operator: Exists
+ - effect: "NoSchedule"
+ operator: "Equal"
+ key: "node-role.kubernetes.io/master"
+ affinity:
+ podAntiAffinity:
+ requiredDuringSchedulingIgnoredDuringExecution:
+ - topologyKey: "kubernetes.io/hostname"
+ labelSelector:
+ matchLabels:
+ k8s-app: kube-dns
+ nodeAffinity:
+ preferredDuringSchedulingIgnoredDuringExecution:
+ - weight: 100
+ preference:
+ matchExpressions:
+ - key: node-role.kubernetes.io/master
+ operator: In
+ values:
+ - "true"
volumes:
- name: kube-dns-config
configMap:
--
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