update coredns 1.4.0

roles/cluster-addon/templates/coredns.yaml.j2

@@ -70,7 +70,7 @@ data:
             fallthrough in-addr.arpa ip6.arpa
         }
         prometheus :9153
-        proxy . /etc/resolv.conf
+        forward . /etc/resolv.conf
         cache 30
         loop
         reload
@@ -103,13 +103,16 @@ spec:
       annotations:
         seccomp.security.alpha.kubernetes.io/pod: 'docker/default'
     spec:
+      priorityClassName: system-cluster-critical
       serviceAccountName: coredns
       tolerations:
         - key: "CriticalAddonsOnly"
           operator: "Exists"
+      nodeSelector:
+        beta.kubernetes.io/os: linux
       containers:
       - name: coredns
-        image: coredns/coredns:1.2.6
+        image: coredns/coredns:1.4.0
         imagePullPolicy: IfNotPresent
         resources:
           limits:
@@ -141,6 +144,11 @@ spec:
           timeoutSeconds: 5
           successThreshold: 1
           failureThreshold: 5
+        readinessProbe:
+          httpGet:
+            path: /health
+            port: 8080
+            scheme: HTTP
         securityContext:
           allowPrivilegeEscalation: false
           capabilities:
@@ -185,4 +193,3 @@ spec:
   - name: metrics
     port: 9153
     protocol: TCP
-    targetPort: 9153