tildes/ansible/roles/ipv6_networking/tasks/main.yml

---
- name: Enable IPv6 networking
  blockinfile:
    path: /etc/network/interfaces
    block: |
      iface {{ ipv6_device }} inet6 static
          address {{ ipv6_address }}
          netmask 64

      post-up sleep 5; /sbin/ip -family inet6 route add {{ ipv6_gateway }} dev {{ ipv6_device }}
      post-up sleep 5; /sbin/ip -family inet6 route add default via {{ ipv6_gateway }}
      pre-down /sbin/ip -family inet6 route del default via {{ ipv6_gateway }}
      pre-down /sbin/ip -family inet6 route del {{ ipv6_gateway }} dev {{ ipv6_device }}

# apt seems to hang a lot when using IPv6
- name: Force apt not to use IPv6
  lineinfile:
    path: /etc/apt/apt.conf.d/99force-ipv4
    line: Acquire::ForceIPv4 "true";
    create: true
    owner: root
    group: root
    mode: 0644