Re: [PATCH RFC] docs: Add minimum version depencency policy document

[George Dunlap <George.Dunlap@xxxxxxxxxx>]

> On Sep 30, 2020, at 2:11 PM, Jan Beulich <jbeulich@xxxxxxxx> wrote:
> 
> On 30.09.2020 14:57, George Dunlap wrote:
>> --- /dev/null
>> +++ b/docs/policies/dependency-versions.rst
>> @@ -0,0 +1,76 @@
>> +.. SPDX-License-Identifier: CC-BY-4.0
>> +
>> +Build and runtime dependencies
>> +==============================
>> +
>> +Xen depends on other programs and libraries to build and to run.
>> +Chosing a minimum version of these tools to support requires a careful
>> +balance: Supporting older versions of these tools or libraries means
>> +that Xen can compile on a wider variety of systems; but means that Xen
>> +cannot take advantage of features available in newer versions.
>> +Conversely, requiring newer versions means that Xen can take advantage
>> +of newer features, but cannot work on as wide a variety of systems.
> 
> I think "cannot take advantage" is too strict here: It may be more
> cumbersome (and as a result to ugly to maintain), but it ought to
> generally be possible. IOW how about adding "easily"?

Sure.

>> +Specific distro versions supported in this release
>> +--------------------------------------------------
>> +
>> +======== ==================
>> +Distro   Supported releases
>> +======== ==================
>> +Debian   10 (Buster)
>> +Ubuntu   20.10 (Groovy Gorilla), 20.04 (Focal Fossa), 18.04 (Bionic 
>> Beaver), 16.04 (Xenial Xerus)
>> +OpenSUSE Leap 15.2
>> +SLES     SLES 11, 12, 15
> 
> SLE 11 has all support packs in LTSS mode already, so as long as this
> mode is what's equivalent to or even less than "Maintenance updates"
> in what you did say for RHEL, it may want dropping. (Personally I'd
> prefer if we remained sufficiently compatible, but I realize I may be
> the only one.)
> 
> Additionally in service packs things like compiler or binutils versions
> often get updated, so e.g. "SLES 11" alone is not sufficient to know
> what's meant to be supported, it would likely need to be "SLES 11 SP4"
> and alike, just like you also specify a minor version for some of the
> other distros. SLES versions not yet in LTSS at this point are, if I'm
> not mistaken, 12 SP5, 15 SP1, and 15 SP2.

Right, part of the reason this is ‘RFC’ is to get feedback from people who 
actually know something about their various distros.

The list above was made by trying to make sense of the table in the link above 
(https://www.suse.com/lifecycle/).  I think it’s important to have references 
such that the release manager can easily update this list every release.  Do 
you think you could provide a better link?

Thanks,
 -George