Date: Tue, 28 Jul 2020 18:10:33 +0200
From: Natanael Copa <ncopa@alpinelinux.org>
To: Ariadne Conill <ariadne@dereferenced.org>
Cc: ~alpine/devel@lists.alpinelinux.org
Subject: Re: Proposed system change: ifupdown-ng as default network device
 manager
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On Tue, 28 Jul 2020 09:36:13 -0600
Ariadne Conill <ariadne@dereferenced.org> wrote:

> Hello,

Hi,

> 
> At present, Alpine uses BusyBox ifupdown as default network device manager, 
> and a few additional 'addon' packages which provide additional scripts that 
> interact with ifupdown.
> 
> We additionally provide Debian ifupdown and, more recently, ifupdown-ng as 
> alternatives.
> 
> This has gotten us very far over the past decade.  However, in many 
> situations, ifupdown is quite limited, such as in dual-stack scenarios and 
> complex configurations where virtual devices depend on parent devices to be 
> brought up first.
> 
> ## What is ifupdown-ng?
> 
> ifupdown-ng is a lightweight network device manager that is backwards 
> compatible with Debian ifupdown and busybox ifupdown.
...

This is awesome!
 
> Another benefit to ifupdown-ng is the executor concept.  With the current addon 
> scripts, they automatically run for every interface at bring-up and take-down.  
> This means that a misconfiguration may result in the addon script doing 
> something to an interface that was not intended.  By contrast, if you use 
> ifupdown-ng's executors, they will only run when explicitly requested with a 
> use statement.
> 
> ifupdown-ng is 100% backwards compatible with ifupdown, 

This is where I am sold.

> and can even 
> automatically convert an /e/n/i file to use the new syntax with the new 
> ifquery(8) utility, but that's optional.

What are the current limitations?

 
> ## Benefits to Alpine
> 
> * The networking initscript can start interfaces more intelligently by 
> leveraging ifquery(8).  Right now this is achieved by attempting to parse the 
> /e/n/i file with awk.  Instead, we can change networking initscript to bring 
> interfaces up in order according to the dependency tree.

This should solve https://gitlab.alpinelinux.org/alpine/aports/-/issues/11562

> * Configuration of IPv4+IPv6 dual-stack environment is simplified, as
> you can just specify a dual-stack configuration.  Right now to use
> dual-stack, you have to either use up/down statements or use Debian
> ifupdown which is still limited to configuring a single address.
> 
> * Future plans for ifupdown-ng include hotplug support, wifi
> configuration, openrc integration, etc.  Early adoption of
> ifupdown-ng as default network device manager allows for streamlined
> adoption of these later features.
> 
> * If ifupdown is dropped from BusyBox, the difference in install size 
> requirement is only 8KB.

I assume the size would increase as new features are added, but I think
its worth it.
 
> ## Testing
> 
> ifupdown-ng is available in edge right now, in the testing
> repository.  Simply do `apk add ifupdown-ng`.
> 
> ## Contingency Plan
> 
> If ifupdown-ng has release-critical problems, we will simply revert
> the change and continue using BusyBox ifupdown as default, with
> ifupdown-ng as an optional package and revisit this in a future
> release cycle.

sounds good to me.

> 
> ## Timeline
> 
> I would like to flip the default sometime in September, before
> feature freeze, but allowing users enough time to test and validate
> ifupdown-ng with their setups.

sounds good.

Thank you for you work on this!

-nc

> 
> Ariadne
>