Allow subdomains of dns_domain and fix kubelet restarts

* Add a var for ndots (default 5) and put it hosts' /etc/resolv.conf.
* Poke kube dns container image to v1.7
* In order to apply changes to kubelet, notify it to
be restarted on changes made to /etc/resolv.conf. Ignore errors as the kubelet
may yet to be present up to the moment of the notification being processed.
* Remove unnecessary kubelet restart for master role as the node role ensures
it is up and running. Notify master static pods waiters for apiserver,
scheduler, controller-manager instead.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

roles/kubernetes/master/handlers/main.yml

@@ -4,12 +4,14 @@
   notify:
     - Master | reload systemd
     - Master | reload kubelet
+    - Master | wait for master static pods
 
-- name: wait for master static pods
+- name: Master | wait for master static pods
   command: /bin/true
   notify:
-    - wait for kube-scheduler
-    - wait for kube-controller-manager
+    - Master | wait for the apiserver to be running
+    - Master | wait for kube-scheduler
+    - Master | wait for kube-controller-manager
 
 - name: Master | reload systemd
   command: systemctl daemon-reload
@@ -20,16 +22,23 @@
     name: kubelet
     state: restarted
 
-- name: wait for kube-scheduler
+- name: Master | wait for kube-scheduler
   uri: url=http://localhost:10251/healthz
   register: scheduler_result
   until: scheduler_result.status == 200
   retries: 15
   delay: 5
 
-- name: wait for kube-controller-manager
+- name: Master | wait for kube-controller-manager
   uri: url=http://localhost:10252/healthz
   register: controller_manager_result
   until: controller_manager_result.status == 200
   retries: 15
   delay: 5
+
+- name: Master | wait for the apiserver to be running
+  uri: url=http://localhost:8080/healthz
+  register: result
+  until: result.status == 200
+  retries: 10
+  delay: 6