Configuration file style guide

To make a configuration file more reusable:

• Use values from Pillar data, instead of hardcoding values.

• Set sensible defaults, for example:

  {{ bind_address|default('127.0.0.1') }}
  

• Make values optional, for example:

  {%- if 'ipv6' in pillar.apache %}
  Listen [{{ pillar.apache.ipv6 }}]:443
  {%- endif %}