Bump kube-dns addon version to v19

Author: aaronlevy

pkg/asset/internal/templates.go

@@ -282,27 +282,33 @@ spec:
 	DNSDeploymentTemplate = []byte(`apiVersion: extensions/v1beta1
 kind: Deployment
 metadata:
-  name: kube-dns-v17.1
+  name: kube-dns-v19
   namespace: kube-system
   labels:
     k8s-app: kube-dns
-    version: v17.1
+    version: v19
     kubernetes.io/cluster-service: "true"
 spec:
   replicas: 1
   template:
     metadata:
       labels:
         k8s-app: kube-dns
-        version: v17.1
+        version: v19
         kubernetes.io/cluster-service: "true"
+      annotations:
+        scheduler.alpha.kubernetes.io/critical-pod: ''
+        scheduler.alpha.kubernetes.io/tolerations: '[{"key":"CriticalAddonsOnly", "operator":"Exists"}]'
     spec:
       containers:
       - name: kubedns
-        image: gcr.io/google_containers/kubedns-amd64:1.5
+        image: gcr.io/google_containers/kubedns-amd64:1.7
         resources:
+          # TODO: Set memory limits when we've profiled the container for large
+          # clusters, then set request = limit to keep this container in
+          # guaranteed class. Currently, this container falls into the
+          # "burstable" category so the kubelet doesn't backoff from restarting it.
           limits:
-            cpu: 100m
             memory: 170Mi
           requests:
             cpu: 100m
@@ -321,11 +327,14 @@ spec:
             path: /readiness
             port: 8081
             scheme: HTTP
+          # we poll on pod startup for the Kubernetes master service and
+          # only setup the /readiness HTTP server once that's available.
           initialDelaySeconds: 30
           timeoutSeconds: 5
         args:
-          - --domain=cluster.local.
-          - --dns-port=10053
+        # command = "/kube-dns"
+        - --domain=cluster.local.
+        - --dns-port=10053
         ports:
         - containerPort: 10053
           name: dns-local
@@ -350,19 +359,22 @@ spec:
         image: gcr.io/google_containers/exechealthz-amd64:1.1
         resources:
           limits:
-            cpu: 10m
             memory: 50Mi
           requests:
             cpu: 10m
+            # Note that this container shouldn't really need 50Mi of memory. The
+            # limits are set higher than expected pending investigation on #29688.
+            # The extra memory was stolen from the kubedns container to keep the
+            # net memory requested by the pod constant.
             memory: 50Mi
         args:
-        - -cmd=nslookup kubernetes.default.svc.cluster.local 127.0.0.1 >/dev/null
+        - -cmd=nslookup kubernetes.default.svc.cluster.local 127.0.0.1 >/dev/null && nslookup kubernetes.default.svc.cluster.local 127.0.0.1:10053 >/dev/null
         - -port=8080
         - -quiet
         ports:
         - containerPort: 8080
           protocol: TCP
-      dnsPolicy: Default
+      dnsPolicy: Default  # Don't use cluster DNS.
 `)
 	DNSSvcTemplate = []byte(`apiVersion: v1
 kind: Service