[CentOS-devel] Before You Get Mad About The CentOS Stream Change, Think About…

Johnny Hughes

johnny at centos.org
Wed Dec 23 16:00:56 UTC 2020


On 12/23/20 1:14 AM, Gordon Messmer wrote:
> On 12/22/20 10:36 PM, Nico Kadel-Garcia wrote:
>> It's why I say they're taags" and find the model
>> mentioned here that "it's all one branch" to not match reality
> 
> 
> For fun, I'll try again:
> 
> RHEL point releases are branches.  7.6 is a branch.  7.7 is a branch. 
> You can continue running 7.6 and receive security updates after 7.7 is
> released.  Those updates may include packages built specifically for
> 7.6, and not just a selection of the packages for 7.7.  They're
> maintained in parallel, at the same time.  They're branches.
> 
> CentOS point releases weren't individual branches.  There was only one
> CentOS 7 branch.  CentOS 7.6 was just a point in time along the lifetime
> of CentOS 7.  7.6 is not literally a tag, but it's the closest analogy. 
> There was no continued support for CentOS 7.6 after CentOS 7.7 was
> released.  If there's no parallel maintenance, there is only one branch.
> 
> In an VCS, you can create a branch and continue work, and later create
> another branch off of that and continue work, but if you never add any
> work to an older branch after a new branch is created, then you're only
> using branches in a very superficial sense.  There are technically
> branches, but there's no difference in that workflow between several
> branches and just one, because you have just one linear history
> containing every commit.  This resembles CentOS updates.
> 
> RHEL point releases get updates that aren't just updates for a later
> release.  As an analogy, there are updates in the older branches that
> aren't in the new branches, unlike CentOS.
> 
> CentOS has just one branch:
> 
> * 7.5
>  \
>   * 7.6
>    \
>     * 7.7
> 
> RHEL has multiple branches that overlap in time:
> 
> * ---- 7.5
>  \
>   * ---- 7.6
>    \
>     * ---- 7.7
>

This is 100% exactly accurate.  AND, this is how it has been since the
beginning of CentOS Linux.

Stream is really no different than this.  Each major version is one tree
(IE CentOS Stream 8, CentOS Stream 9)

There will be 5 years for each stream tree (after the release of the
RHEL 8.0 or RHEL 9.0 official release).  This results in about 2 years
of overlap (or maybe slightly more) of 2 versions of Stream being active
at the same time so you can plan a migration from one to the other.


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