Add option to disable ipv6 dns lookup

New variable disable_ipv6_dns in kubernetes/preinstall.

roles/kubernetes/preinstall/tasks/main.yml

@@ -97,6 +97,14 @@
   with_items: "{{required_pkgs | default([]) | union(common_required_pkgs|default([]))}}"
   when: ansible_os_family != "CoreOS"
 
+- name: Disable IPv6 DNS lookup
+  lineinfile:
+    dest: /etc/gai.conf
+    line: "precedence ::ffff:0:0/96  100"
+    state: present
+    backup: yes
+  when: disable_ipv6_dns and ansible_os_family != "CoreOS"
+
 # Todo : selinux configuration
 - name: Set selinux policy to permissive
   selinux: policy=targeted state=permissive