Fedora Ring 0 definition

[Josh Boyer]

On Wed, Sep 2, 2015 at 2:59 PM, Brendan Conoboy <blc at redhat.com> wrote:
> Re-sending this with a better title so people might read it ;-)

I read it last week.  Perhaps the lack of commentary isn't because of
the title.  It's because there is nothing new here.  The proposal
boils down to "collection/classification of packages that are
important."  There is nothing about how to actually start here.  See
below.

>> At Flock 2015 there was a 2 hour session on the subject of rings which
>> are basically policy zones inhabited by packages.  Right now fedora
>> packaging has 1 policy, so the entire OS is in a single ring. Creating
>> more rings means creating more policies.  By doing this Fedora can
>> become adopt the flexible to appeal to diverse development communities
>> and thus grow.  The general consensus at Flock was that Environments
>> and Stacks should take the lead in helping to define new rings, and
>> especially how the rings interact.  As a side note, everyone agreed
>> the word "rings" breaks down the further you get away from the center,
>> but nobody has come up with something better yet (Venns? Blobs?
>> Zones?).  A week or so ago, a small Environments and Stacks meeting
>> took place where it was generally agreed that the Base working group
>> was the right place to define Ring 0.  That brings us to this
>> morning's BaseWG meeting.  I talked a lot so here is a rough recap
>> integrating a few of the questions and comments people had (Do read
>> the log if you have time!)
>>
>> Right now the Fedora distribution is 1 ring, let's call it ring 1. The
>> distribution contains an operating system and numerous applications
>> that run on that operating system.  When we talk about defining ring 0
>> we're really talking about distinguishing between the operating system
>> and the applications that run on top of it.
>>
>> We want to go from this:
>>
>> Ring 1: The Fedora Distribution
>>
>> To this:
>>
>> The Fedora Distribution:
>> Ring 0: The Linux Operating System
>> Ring 1: The Applications and Stacks
>>
>> It seems quite modest, but working through the details on what this
>> means is hard.  What is an operating system in the Linux context? Ring
>> 0 will likely have the strictest set of policies of all the rings, so
>> we want to keep it as small as possible, but it is more than a minimal
>> install.  These are the traits of rings in general and ring 0 in
>> particular as I see it:

The original incarnation of the Base WG defined this already.  How
does your definition differ?  For that matter, how does your
definition differ from the existing critpath concept that is already
implemented in bodhi?

>> 1. Ring 0 is a repository of rpm packages built in koji.
>>
>> 2. Ring 0 contains, but is not limited to, the minimal install of
>> packages to go from Power On to a login prompt.

Define login prompt.

>> 3. Ring 0 passes repoclosure on its own (Packages listed as hard
>> "Requires" in a ring 0 spec file are themselves are implicitly ring 0).
>>
>> 4. Ring 0 is not self hosting.  Packages listed in "BuildRequires" do
>> not need to be members of Ring 1.  This isn't ideal, but it's a
>> practical consideration.

These match the previous definition that the Base WG came up with.
Nothing came of that except the dependency reduction work that a few
people jumped into and Harald bravely carried on with.

>> 5. Ring membership is at the source package level, not the binary
>> package.  If one source package's binary/noarch sub-package is in ring
>> 0, all sub-packages are in ring 0.

Also the same as before.

>> 6. Ring 0 contains the minimal libraries that define the OS API/ABI,
>> such as glibc.  This probably happens implicitly by #3, repoclosure.
>>
>> 7. Ring 0 contains the tools needed to update existing packages and
>> install new packages.

Which is where a lot of the bulk came from in the original definition.
This brings in python at a minimum.  If by tools you mean "graphical
updaters" then you're almost back to Ring 0 being Fedora distribution.
So precise language is needed.

(Also, the original definition included Anaconda because you need
something to actually install Fedora Ring 0 with and that brought in
GTK, etc).)

>> That's the starting point, but it is by no means comprehensive.  The
>> OS probably provides specific services beyond the ability to login,
>> for instance.  Which styles of boot are supported?  Where does
>> installation infrastructure like anaconda land?  This is equal parts
>> philosophy and practicality.  Also, policies for ring 0 may differ
>> from what Base has previously adopted: Do we create a ring 0 minimal
>> compose since we already need to check repoclosure?  This might be a
>> great way to refactor primary/secondary such that we can gracefully
>> transition i686 down and secondary arches up.  Lots of opportunities,
>> much to consider.

That's what we said last time :)

Seriously, I'm not meaning to dissuade you at all here.  I'm
suggesting that you do NOT wait for lots of people to chime in on what
Ring 0 is and instead come up with a concrete definition for it.
That's the what.  You're almost there.

What is going to get you the most commentary comes after that.  The
why and how.  Why is Ring 0 defined this way, and how is this proposal
going to change things within the Fedora project/Fedora distribution?

Answer those questions, particularly the impact to package
maintainers, and you'll get a lot more feedback.  I promise.

josh