Introduction
============
ifupdown2 is a replacement for the debian network interface
management package ifupdown. It is ifupdown re-written in python. It
maintains the original ifupdown pluggable architecture and extends it further.

It comes as two packages:
    * python-ifupdown2
    * python-ifupdown2-addons

(Packaging may change in the future)

python-ifupdown2
----------------

The python-ifupdown2 package provides the infrastructure for
parsing /etc/network/interfaces file, loading, scheduling, template parsing,
state management and interface dependency generation of interfaces.

It dynamically loads python modules from /usr/share/ifupdownmodules (provided
 by the python-ifupdown2-addons package). To remain compatible with other
packages that depend on ifupdown, it also executes scripts under /etc/network/.
To make the transition smoother, a python module under
/usr/share/ifupdownmodules will override a script by the same name under
/etc/network/.

It publishes an interface object which is passed to all loadble python
modules. For more details on adding a addon module, see the section on
adding python modules.

ifupdown2 module calls all modules for every interface declared in the
/etc/network/interfaces file.


python-ifupdown2-addons
-----------------------

The python-ifupdown2-addons package contains ifupdown2 addon modules.

addon modules are responsible for applying interface configuration.
The modules are installed under /usr/share/ifupdownmodules.

Each module can declare its own set of supported attributes. Each module
is passed the iface object (which is a representation of /etc/network/interfaces
iface entry). Each module is also passed the operation to be performed.

Example modules are /usr/share/ifupdownmodules/address.py,
/usr/share/ifupdownmodules/bridge.py etc

The order in which these modules are invoked is listed in 
/var/lib/ifupdownaddons/addons.conf. There is a ifaddon utility in the works
to better manage the module ordering.

For details on how to add a module, see the api reference and development
documentation.