[Nodelocal DNS cache] Mount host /run/xtables.lock in nodelocaldns container (#4074)

* Mount host /run/xtables.lock in nodelocaldns container

* fix typo in nodelocaldns daemonset manifest yml

* Add prometheus scrape annotation, updateStrategy and reduce termination grace period

* fix indentation

* actually fix it..

* Bump k8s-dns-node-cache tag to 1.15.1 (fixes https://github.com/kubernetes/dns/issues/282)

roles/download/defaults/main.yml

@@ -194,7 +194,7 @@ coredns_version: "1.2.6"
 coredns_image_repo: "coredns/coredns"
 coredns_image_tag: "{{ coredns_version }}"
 
-nodelocaldns_version: "1.15.0"
+nodelocaldns_version: "1.15.1"
 nodelocaldns_image_repo: "k8s.gcr.io/k8s-dns-node-cache"
 nodelocaldns_image_tag: "{{ nodelocaldns_version }}"
 

roles/kubernetes-apps/ansible/tasks/nodelocaldns.yml

@@ -6,7 +6,7 @@
   with_items:
     - { name: nodelocaldns, file: nodelocaldns-config.yml, type: configmap }
     - { name: nodelocaldns, file: nodelocaldns-sa.yml, type: sa }
-    - { name: nodelocaldns, file: nodelocaldns-deamonset.yml, type: daemonset }
+    - { name: nodelocaldns, file: nodelocaldns-daemonset.yml, type: daemonset }
   register: nodelocaldns_manifests
   vars:
     clusterIP: "{{ skydns_server }}"

roles/kubernetes-apps/ansible/templates/nodelocaldns-daemonset.yml.j2

@@ -15,6 +15,9 @@ spec:
     metadata:
       labels:
         k8s-app: nodelocaldns
+      annotations:
+        prometheus.io/scrape: 'true'
+        prometheus.io/port: '9253'
     spec:
 {% if kube_version is version('v1.11.1', '>=') %}
       priorityClassName: system-cluster-critical
@@ -62,6 +65,8 @@ spec:
         volumeMounts:
         - name: config-volume
           mountPath: /etc/coredns
+        - name: xtables-lock
+          mountPath: /run/xtables.lock
       volumes:
         - name: config-volume
           configMap:
@@ -69,4 +74,14 @@ spec:
             items:
             - key: Corefile
               path: Corefile
-      terminationGracePeriodSeconds: 30
+        - name: xtables-lock
+          hostPath:
+            path: /run/xtables.lock
+            type: FileOrCreate
+      # Minimize downtime during a rolling upgrade or deletion; tell Kubernetes to do a "force
+      # deletion": https://kubernetes.io/docs/concepts/workloads/pods/pod/#termination-of-pods.
+      terminationGracePeriodSeconds: 0
+  updateStrategy:
+    rollingUpdate:
+      maxUnavailable: {{ serial | default('20%') }}
+    type: RollingUpdate