Ansible Role: ipaddr_hash

Provides a Jinja2 filter plugin to compute an IP address given a prefix and a seed, e.g., the inventory_hostname.

This plugin is useful for people seeking a predictable addressing scheme for statically assigned IPv6 addresses based on hostnames.

The algorithm used to derive an ip is simple:

ip = prefix + (sha256(seed) & hostmask)

Requirements

None

Role Variables

None

Dependencies

• Python module netaddr on controller.

Example Playbook

Usage of ipaddr_hash filter:

- hosts: localhost
  tasks:
    - import_role:
        name: znerol.ipaddr_hash

    - debug:
        msg: "Generated IPv6 address for example.com with prefix '2001:db8::/64' is {{ '2001:db8::/64' | ipaddr_hash('example.com') }}"

This should generate the address: 2001:db8::13d2:1255:86ce:1947.

See test/test.yml for sample input/output.

License

GPLv3