Avahi-Alias

There are currently no configuration options to set up CNAME mDNS entries with avahi-daemon. These scripts are an adaption of the script at http://www.avahi.org/wiki/Examples/PythonPublishAlias with the following modification:

• Turn the script into a daemon via Upstart.
• Reads CNAMES from flat files in /etc/avahi/alias.d.

Requirements

avahi-alias requires python-avahi. The installation below assumes Upstart and has been tested on Ubuntu 12.04.

Installation using Upstart

1. Copy avahi-alias to /usr/sbin/avahi-alias.
2. Copy avahi-alias.upstart to /etc/init/avahi-alias.conf

Usage

The script reads all the files in /etc/avahi/alias.d. Each non-blank line in each file is interpreted as a CNAME to register. The names must include the domain (e.g., .local).

Example:

	# mkdir -p /etc/avahi/alias.d
	# echo app1.local >> /etc/avahi/alias.d/apps
	# echo app2.local >> /etc/avahi/alias.d/apps
	# echo db.local >> /etc/avahi/alias.d/services
	# service avahi-alias restart

Your machine now has three has CNAMEs: "app1.local", "app2.local", and "db.local".

Motivation

This script is to inject the equivalent of domain CNAME resource records into local DNS-SD records for entries. This allows multiple hostname to resolve to the current host. The need for this is because avahi.hosts will automatically filter out name collisions, and there's currently no means for adding these values through existing service configuration.