Introduce dns_mode and resolvconf_mode and implement docker_dns mode

Also update reset.yml to do more dns/network related cleanup.

roles/kubernetes/node/templates/kubelet.j2

@@ -12,9 +12,9 @@ KUBELET_HOSTNAME="--hostname-override={{ ansible_hostname }}"
 {% set kubelet_args_base %}--pod-manifest-path={{ kube_manifest_dir }} --pod-infra-container-image={{ pod_infra_image_repo }}:{{ pod_infra_image_tag }}{% endset %}
 
 {# DNS settings for kubelet #}
-{% if dns_setup|bool and skip_dnsmasq|bool %}
+{% if dns_mode == 'kubedns' %}
 {% set kubelet_args_cluster_dns %}--cluster_dns={{ skydns_server }}{% endset %}
-{% elif dns_setup|bool %}
+{% elif dns_mode == 'dnsmasq_kubedns' %}
 {% set kubelet_args_cluster_dns %}--cluster_dns={{ dns_server }}{% endset %}
 {% else %}
 {% set kubelet_args_cluster_dns %}{% endset %}

roles/kubernetes/preinstall/tasks/main.yml

@@ -172,6 +172,7 @@
   tags: [bootstrap-os, etchosts]
 
 - include: resolvconf.yml
+  when: dns_mode != 'none' and resolvconf_mode == 'host_resolvconf'
   tags: [bootstrap-os, resolvconf]
 
 - name: Check if we are running inside a Azure VM

roles/kubernetes/preinstall/tasks/set_resolv_facts.yml

@@ -67,7 +67,7 @@
 - name: pick dnsmasq cluster IP or default resolver
   set_fact:
     dnsmasq_server: |-
-      {%- if skip_dnsmasq|bool and not dns_early|bool -%}
+      {%- if dns_mode == 'kubedns' and not dns_early|bool -%}
         {{ [ skydns_server ] + upstream_dns_servers|default([]) }}
       {%- elif dns_early|bool -%}
         {{ upstream_dns_servers|default([]) }}