Ubuntu Core: how the file-system works

[Luca Dionisi]

On Fri, Jan 20, 2017 at 3:06 PM, Mark Shuttleworth <mark at ubuntu.com> wrote:
> On 20/01/17 05:59, Luca Dionisi wrote:
>> First of all I need to understand how the file-system works. Because I
>> need to edit some system files.
>
> Ubuntu Core is designed to offer a super-reliable and predictable
> upgrade experience, so core system files are often fixed ("immutable").
> It will be interesting to know what you need at the base level so we can
> expose it as a standard config element.

Since my "thingy" is going to sport an experimental routing protocol, I need
to change some files on the fly. For instance /etc/iproute/rt_tables. Which
I already see that is not writeable in my Ubuntu Core install.

Also I am going to use some commands that I haven't yet tested on Ubuntu
Core. Mostly "ip" and "iptables", also in non-default network namespaces.
And I don't know if they need internally write-access to some file.

Do you see anything about it that would be infeasible in a Ubuntu Core as
it currently stands?

If not, what is my next step? Will I need to build a custom Ubuntu Core
image? While testing, would I be able to remount the current image file
system in read-write?

--Luca