[CentOS] Upgrading from CentOS 5.6 to 6.0

[Always Learning]

On Sun, 2011-07-24 at 15:59 +0200, Alexander Dalloz wrote:


> Paul,
> 
> as much as I understand your point of view, I must disagree taking
> upstream's and CentOS's position. Your description reflects a home user
> or an administrator with just less than a handful of systems.

Alexander,

I have 11 servers all running C 5.6 and will stay on 5.x while
everything works satisfactorily. For development and experimentation I
use 2 desktops, laptop and notebook running C 5.6 as a server/client
(server/normal user). The 6.x kernel offers me new development
possibilities.

> CentOS and RHEL aims for the enterprise use. Of course that does not
> imply people can not rely on this stable platform in very small
> environments, but that's not the focus of the OS design.

The operating system comprises several parts. The kernel, Red Hat's
versions of various semi-system/application software, the extras like
clustering and kvm. The focus of the design is to provide a very stable
base upon which many different additions will successfully operate and
co-exist.

Red Hat provide one basic version of their RHEL which can be used both
as a server and as a client (meaning 'normal user' environment). You may
have noticed RH's endorsement of Gnome. RHEL is an enterprise operating
system but enterprise, in the commercial understanding of the word,
means more than a server farm or racks in a data centre. It means the
entire corporation - servers and end-users. From the payroll system to
the chief executive officer's desk. RHEL does all these different tasks
admirably well. 

>  And speaking
> about the enterprise scenario, no serious administrator will risk the
> proper function of his install base by going risky paths.

Is 'risky path' someone wanting to easily upgrade/convert from 5.x to 6.x ?

> Typically the
> OS is just the base for the middleware and application level. Switching
> to a new major level of OS with lots of important changes means, the
> administrator will have to test and adjust his setup of OS and
> application use in multiple aspects. This even applies to applications
> the base OS ships with.

The large? jump from 5.x to 6.x and the resulting pressure on people to
find the problems and solve them is, obviously, time consuming and for
some demanding.

If some (certainly not 'all') of the 'new' 6.x
systems/changes/improvements were available in 5.x, people could
gradually learn about them including any changes. This pre-knowledge
spread over a year, would make major version transitions easier and
quicker. I acknowledge this is not a Centos issue but a Red Hat policy.
A solution is to experiment with the relevant Fedora versions.

> In enterprise environments, where the CentOS systems are more than a
> simple shell box or a trivial webserver, it is more time consuming to
> find all the possible places to adjust the obsolete configurations being
> transferred by an upgrade and to find the tripping points

Hopefully each application has just one configuration file in one known
location. Keeping a set-up simple and ensuring up-to-date documentation
should avoid 'obsolete configurations' existing and 'tripping points'
occurring.


-- 
With best regards,

Paul.
England,
EU.