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99ce689411
Ticket:
Reviewed By: CCR-4268
Testing Done: Tested squashing of interfaces with multiple iface stanzas
This is controlled by ifaceobj_squash config variable in
/etc/network/ifupdown2/ifupdown2.conf.
With ifaceobj_squash=1, ifquery and all commands will
output squashed interfaces.
$cat /etc/network/interfaces
auto swp3
iface swp3
mtu 9000
auto swp3
iface swp3 inet static
address 10.0.17.3/24
auto swp3
iface swp3 inet static
address 10.0.18.3/24
address 2000:1000:1000:1000:3::5/128
$ifquery -a
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet dhcp
auto swp3
iface swp3
mtu 9000
address 10.0.17.3/24
address 10.0.18.3/24
address 2000:1000:1000:1000:3::5/128
When and why do we need this ?
- If we preserve multiple ifaceobjects for the same iface,
it gets tricky in some cases to set default policy
values because the addon module run methods are called
on each ifaceobject.
- Each ifaceobject belonging to the same interface
is treated as a separate interface. It is difficult
to remember things accross addon module run methods
- we have a few hacks in place which we would like to
get rid of
Why not turn it on by default ?
- still debating about it. Dont want to break existing
scripts with change of output. Will get some feedback before
I switch the default to squash.
python-ifupdown2
================
This package is a replacement for the debian ifupdown package.
It is ifupdown re-written in python. It maintains the original ifupdown
pluggable architecture and extends it further.
The python-ifupdown2 package provides the infrastructure for
parsing /etc/network/interfaces file, loading, scheduling and state
management 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.
pluggable python modules:
=========================
Unlike original ifupdown, all interface configuration is moved to external
python modules. That includes inet, inet6 and dhcp configurations.
A set of default modules are provided by the python-ifupdown2-addons deb.
python-ifupdown2 expects a few things from the pluggable modules:
- the module should implement a class by the same name
- the interface object (class iface) and the operation to be performed is
passed to the modules
- the python addon class should provide a few methods:
- run() : method to configure the interface.
- get_ops() : must return a list of operations it supports.
eg: 'pre-up', 'post-down'
- get_dependent_ifacenames() : must return a list of interfaces the
interface is dependent on. This is used to build the dependency list
for sorting and executing interfaces in dependency order.
- if the module supports -r option to ifquery, ie ability to construct the
ifaceobj from running state, it can optionally implement the
get_dependent_ifacenames_running() method, to return the list of
dependent interfaces derived from running state of the interface.
This is different from get_dependent_ifacenames() where the dependent
interfaces are derived from the interfaces config file (provided by the
user).
Example: Address handling module /usr/share/ifupdownaddons/address.py
build
=====
- get source
- install build dependencies:
apt-get install python-stdeb
apt-get install python-docutils
- cd <python-ifupdown2 sourcedir> && ./build.sh
(generates python-ifupdown2-<ver>.deb)
install
=======
- remove existing ifupdown package
dpkg -r ifupdown
- install python-ifupdown2 using `dpkg -i`
- or install from deb
dpkg -i python-ifupdown2-<ver>.deb
- note that python-ifupdown2 requires python-ifupdown2-addons package to
function. And python-ifupdown2-addons deb has an install dependency on
python-ifupdown2