What's in a (CentOS) version number?
The relationship between CentOS and Red Hat has always been interesting. Red Hat provides the source packages that, after removal of branding elements, are built into the CentOS release. By one measure, CentOS is sustaining freeloaders who want to benefit from Red Hat's work without paying for it. By another, CentOS helps Red Hat by bringing users into its ecosystem; some of those users eventually become paying Red Hat customers. So it is not surprising that users can see the recent acquisition of CentOS by Red Hat in two different lights: it's either an attempt to squash a competing distribution or an effort to sustain that distribution with much-needed support.
Either way, changes were always going to happen after the acquisition. CentOS users will certainly be happy about the first of those changes: support for CentOS developers so they can work on the distribution full time, and support for the infrastructure needed to keep CentOS going. But when CentOS project leader Karanbir Singh proposed a change to the seemingly trivial issue of version numbers, users were quick to express their disapproval.
Traditionally, CentOS releases have used the same version number as the RHEL release they are based on; CentOS 6.5 is a rebuild of the RHEL 6.5 release, for example. The CentOS developers now want to change to a scheme where the major number matches the RHEL major number, but the minor number is generated from the release date. So, if the CentOS version of RHEL 7.0 were to come out in July 2014, it might have a version number like 7.1407. Derivative releases from CentOS special interest groups (SIGs) would have an additional, SIG-specific tag appended to that number.
To the CentOS developers, this change offers a number of advantages. The close tie with RHEL version numbers, it is claimed, can confuse users into believing that a release is supported with security updates when it is not; see this detailed message from Johnny Hughes for an explanation of the reasoning there. Putting the release date into the version number makes the age of a release immediately obvious, presumably inspiring users to upgrade to current releases. This scheme would also make it easier to create releases that are not directly tied to RHEL releases; that is something that the SIGs, in particular, would like to be able to do.
Supporting the SIGs is a big part of the project's plan for the future in general. Karsten Wade described it this way:
So it seems that CentOS wants to follow Red Hat into the cloud. Simply providing a rebuild of RHEL is not as exciting as it once was, so the project wants to expand into other areas where, it is hoped, more users are to be found.
It should be possible to expand in this way as long as the core CentOS distribution remains what it has always been. Unfortunately, some users are worried that things will not be that way. Ljubomir Ljubojevic, the maintainer of the CentOS Facebook page, described his feelings about the change:
A large number of "me too" posts made it clear that Ljubomir is not alone in feeling this way. There is a lot of concern that the project might break the core distribution and that adopting a new version numbering scheme looks like a first step in that direction.
For their part, the CentOS developers have tried to address that concern. Karanbir stated directly that there is no plan to change how the core distribution is managed:
For the most part, the users in the discussion seemed to accept that promise, but that made them no happier about the version numbering change. The date-based numbers, they say, make it harder to know which version of RHEL a CentOS release is based on, and it can make it harder to justify installations (or upgrades) to management. All told, it was hard to find a single supportive voice for this change outside of the CentOS core developers.
Those developers have not said anything about what changes, if any, they
might make to their plans in response to the opposition on the list. They
are in a bit of a difficult position: they want to make changes aimed at
attracting a broader set of users, but those changes appear threatening to
their existing users, most of whom are quite happy with the distribution as
it is now and are not asking for anything different. If the existing users
start to
feel that their concerns are not being heard, they may start to look for
alternatives. In this case, the powers that be at CentOS may want to make
a show of listening to those users and finding a way to resolve their
version number concerns that doesn't appear to break the strong connection
between RHEL and CentOS releases.
