Ensure /etc/resolv.conf content for CoreOS

Use cloud-init config to replace /etc/resolv.conf with the
content for kubelet to properly configure hostnet pods.

Do not use systemd-resolved yet, see
https://coreos.com/os/docs/latest/configuring-dns.html
"Only nss-aware applications can take advantage of the
systemd-resolved cache. Notably, this means that statically
linked Go programs and programs running within Docker/rkt
will use /etc/resolv.conf only, and will not use the
systemd-resolve cache."

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

roles/dnsmasq/handlers/main.yml

@@ -21,11 +21,23 @@
   notify:
     - Dnsmasq | reload resolvconf
     - Dnsmasq | reload kubelet
+  when: ansible_os_family != "CoreOS"
+
+- name: Dnsmasq | update resolvconf for CoreOS
+  command: /bin/true
+  notify:
+    - Dnsmasq | apply resolvconf cloud-init
+    - Dnsmasq | reload kubelet
+  when: ansible_os_family == "CoreOS"
 
 - name: Dnsmasq | reload resolvconf
   command: /sbin/resolvconf -u
   ignore_errors: true
 
+- name: Dnsmasq | apply resolvconf cloud-init
+  command: /usr/bin/coreos-cloudinit --from-file {{ resolveconf_cloud_init_conf }}
+  when: ansible_os_family == "CoreOS"
+
 - name: Dnsmasq | reload kubelet
   service:
     name: kubelet