Introduce dns_mode and resolvconf_mode and implement docker_dns mode

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

roles/reset/tasks/main.yml

@@ -1,7 +1,7 @@
 ---
 
 - name: reset | stop services
-  service: name={{item}} state=stopped
+  service: name={{ item }} state=stopped
   with_items:
     - kubelet
     - etcd
@@ -16,13 +16,26 @@
     - etcd
   register: services_removed
 
+- name: reset | remove docker dropins
+  file:
+    path: "/etc/systemd/system/docker.service.d/{{ item }}"
+    state: absent
+  with_items:
+    - docker-dns.conf
+    - docker-options.conf
+  register: docker_dropins_removed
+
 - name: reset | systemctl daemon-reload
   command: systemctl daemon-reload
-  when: services_removed.changed
+  when: services_removed.changed or docker_dropins_removed.changed
 
 - name: reset | remove all containers
   shell: "{{ docker_bin_dir }}/docker ps -aq | xargs -r docker rm -fv"
 
+- name: reset | restart docker if needed
+  service: name=docker state=restarted
+  when: docker_dropins_removed.changed
+
 - name: reset | gather mounted kubelet dirs
   shell: mount | grep /var/lib/kubelet | awk '{print $3}' | tac
   register: mounted_dirs
@@ -42,6 +55,40 @@
     - /etc/cni
     - /etc/nginx
     - /etc/dnsmasq.d
+    - /etc/dnsmasq.conf
+    - /etc/dnsmasq.d-available
     - /etc/etcd.env
     - /etc/calico
     - /opt/cni
+    - /etc/dhcp/dhclient.d/zdnsupdate.sh
+    - /etc/dhcp/dhclient-exit-hooks.d/zdnsupdate
+    - "{{ bin_dir }}/kubelet"
+
+- name: reset | remove dns settings from dhclient.conf
+  blockinfile:
+    dest: "{{ item }}"
+    state: absent
+    follow: yes
+    marker: "# Ansible entries {mark}"
+  failed_when: false
+  with_items:
+    - /etc/dhclient.conf
+    - /etc/dhcp/dhclient.conf
+
+- name: reset | remove host entries from /etc/hosts
+  blockinfile:
+    dest: "/etc/hosts"
+    state: absent
+    follow: yes
+    marker: "# Ansible inventory hosts {mark}"
+
+- name: reset | Restart network
+  service:
+    name: >-
+      {% if ansible_os_family == "RedHat" -%}
+      network
+      {%- elif ansible_os_family == "Debian" -%}
+      networking
+      {%- endif %}
+    state: restarted
+  when: ansible_os_family != "CoreOS"