[CentOS-docs] Update for FAQ - q.15 & q.31 update & merge

Fri Jun 5 17:30:46 UTC 2015
Karsten Wade <kwade at redhat.com>

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Folks:

A few of us (KB, Johnny, myself) have begun work on updating the main
FAQs on the CentOS wiki. Mainly that means looking over and updating
for any changes that have been going on in the last 18 months as the
project has expanded to include SIG releases, monthly updates of many
new types, new hardware architectures, and so forth.

For this first update we've got this from the FAQ:

q.15:
http://wiki.centos.org/FAQ/General#head-6e2c3746ec45ac3142917466760321e8
68f43c0e
q.31
http://wiki.centos.org/FAQ/General#head-dcca41e9a3d5ac4c6d900a991990fd11
930867d6

The first item is that these questions are repetitive, so I'd like to
combine them in to a single answer. Second is that version numbering
has expanded, so we need to cover monthly updates and so forth.

Circling around on this, we ended up with the following complete
rewrite that would replace q.31 and retire q.15 (thereby making q.31
in to q.30.) How does this update sound?

If we're close enough, I'll push it to live at the start of next week,
and we can always continue iterating on it.

The text below is in Moin Moin format; I was going to do a diff
between the versions but then we differed so wildly in combining and
rewriting that I think a mental diff will work better. A formatted
draft is here:

http://wiki.centos.org/KarstenWade/GeneralFAQUpdateq31q15

Thanks - Karsten

#######################################################################
## begin
== How does CentOS versioning work? ==

 1. CentOS Linux currently has 3 ''major'' released branches that are
active:  CentOS-5, CentOS-6, and CentOS-7.
 1. CentOS Linux releases ''minor'' (point in time) versions of our
major branches. These minor versions are also sometimes called ''point
releases''. Two very important things about CentOS Linux branches are:
  1. The CentOS Project '''ONLY''' provides updates or other changes
for the latest version of each major branch. Thus, if the latest minor
version of CentOS-6 is version 6.6 then the CentOS Project only
provides updated software for this minor version in the 6 branch. If
you are using an older minor version than the latest in a given
branch, then you are missing security and bugfix updates.
  1. When setting up yum repositories on CentOS Linux you should
'''ONLY''' use the single digit for the active branch, which
corresponds to the CentOS Linux major branch.   For example,
http://mirror.centos.org/centos/5/ ,
http://mirror.centos.org/centos/6/ , or
http://mirror.centos.org/centos/7/ . This is because we move all older
minor branches to http://vault.centos.org/ . Remember from the prior
bullet point, no updates are ever added to minor versions of CentOS
Linux once in the vault.
 1. Since minor versions of CentOS are ''point in time'' releases of a
major branch, starting with CentOS-7, we are now using a date code in
our minor versions.  So you will see CentOS-7 (1406) or CentOS-7
(1503) as a version. This is so that one can know, from the release,
when it happened. In the above examples, the minor versions 1406 means
June 2014 and 1503 means March 2015. In older major branches of
CentOS, such as CentOS-6, we numbered things differently. Those
branches are numbered as 6.0, 6.1, 6.2, etc.
  1. You might be wondering why the change with CentOS-7.
   1. We are trying to make sure people understand they can NOT use
older minor versions and still be secure. Therefore, a date in the
minor version allows users to know with a glance when this minor
version was created. If it is older than many months, there is likely
a new version you should look for.
   1. As organizations move from individual servers having individual
functionality to virtual machine farms and cloud / container
implementations, the CentOS Project is now producing VM, cloud, and
container images as well as installer ISOs. These images have dates in
their name by design. We want users to easily be able to know what
major branch and minor release are in these images, again at a glance.
If your CentOS-7 images have 1504 (April 2015) or 20150402 (April 2nd,
2015) in the name then they are based on the latest release that comes
before this date ... in this case CentOS-7 (1503).
 1. You can see which source code from Red Hat Enterprise Linux was
used to create each minor version of CentOS Linux from the chart
entitled "Archived Versions" from http://wiki.centos.org/Download
## end
#######################################################################

- -- 
Karsten 'quaid' Wade        .^\          CentOS Doer of Stuff
http://TheOpenSourceWay.org    \  http://community.redhat.com
@quaid (identi.ca/twitter/IRC)  \v'             gpg: AD0E0C41
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