Merge pull request #37730 from MrHohn/dns-deployment-maxUnavailable

Automatic merge from submit-queue

Set strategy spec for kube-dns to support zero downtime rolling update

From #37728 and coreos/kube-aws#111.

Set `maxUnavailable` to 0 to prevent DNS service outage during update when the replica number is only 1.

Also keeps all kube-dns yaml files in sync.

@bowei @thockin

cluster/addons/dns/skydns-rc.yaml.base

@@ -31,6 +31,10 @@ spec:
   # 1. In order to make Addon Manager do not reconcile this replicas parameter.
   # 2. Default is 1.
   # 3. Will be tuned in real time if DNS horizontal auto-scaling is turned on.
+  strategy:
+    rollingUpdate:
+      maxSurge: 10%
+      maxUnavailable: 0
   selector:
     matchLabels:
       k8s-app: kube-dns

cluster/addons/dns/skydns-rc.yaml.in

@@ -31,6 +31,10 @@ spec:
   # 1. In order to make Addon Manager do not reconcile this replicas parameter.
   # 2. Default is 1.
   # 3. Will be tuned in real time if DNS horizontal auto-scaling is turned on.
+  strategy:
+    rollingUpdate:
+      maxSurge: 10%
+      maxUnavailable: 0
   selector:
     matchLabels:
       k8s-app: kube-dns

cluster/addons/dns/skydns-rc.yaml.sed

@@ -31,6 +31,10 @@ spec:
   # 1. In order to make Addon Manager do not reconcile this replicas parameter.
   # 2. Default is 1.
   # 3. Will be tuned in real time if DNS horizontal auto-scaling is turned on.
+  strategy:
+    rollingUpdate:
+      maxSurge: 10%
+      maxUnavailable: 0
   selector:
     matchLabels:
       k8s-app: kube-dns

cluster/gce/coreos/kube-manifests/addons/dns/skydns-rc.yaml

@@ -11,6 +11,10 @@ spec:
   # 1. In order to make Addon Manager do not reconcile this replicas parameter.
   # 2. Default is 1.
   # 3. Will be tuned in real time if DNS horizontal auto-scaling is turned on.
+  strategy:
+    rollingUpdate:
+      maxSurge: 10%
+      maxUnavailable: 0
   selector:
     matchLabels:
       k8s-app: kube-dns
@@ -57,6 +61,7 @@ spec:
         # command = "/kube-dns"
         - --domain=${DNS_DOMAIN}.
         - --dns-port=10053
+        - --config-map=kube-dns
         - --v=0
         env:
           - name: PROMETHEUS_PORT

cluster/juju/layers/kubernetes/templates/kubedns-rc.yaml

@@ -27,6 +27,10 @@ spec:
   # 1. In order to make Addon Manager do not reconcile this replicas parameter.
   # 2. Default is 1.
   # 3. Will be tuned in real time if DNS horizontal auto-scaling is turned on.
+  strategy:
+    rollingUpdate:
+      maxSurge: 10%
+      maxUnavailable: 0
   selector:
     matchLabels:
       k8s-app: kube-dns
@@ -40,7 +44,7 @@ spec:
     spec:
       containers:
       - name: kubedns
-        image: gcr.io/google_containers/kubedns-{{ arch }}:1.8
+        image: gcr.io/google_containers/kubedns-{{ arch }}:1.9
         resources:
           # TODO: Set memory limits when we've profiled the container for large
           # clusters, then set request = limit to keep this container in
@@ -73,6 +77,7 @@ spec:
         # command = "/kube-dns"
         - --domain={{ pillar['dns_domain'] }}.
         - --dns-port=10053
+        - --config-map=kube-dns
         - --v=0
         - --kube_master_url=http://{{ private_address }}:8080
         {{ pillar['federations_domain_map'] }}