[CentOS-devel] CentOS 7 Public QA, > Release Beginner's Question - Part Duex

Sun Jun 15 17:28:08 UTC 2014
Scott Dowdle <dowdle at montanalinux.org>

Greetings,

----- Original Message -----
> KB - you mention migration paths from 6 to 7 and branding stuff.  Are
> you envisioning a test like taking an up to date c6 installation and
> the yum installing c7 rpms and looking for hiccups and issues?  I'm
> not quite sure I understand what is meant by migration when as yet
> there is no C7 installer or install tree.

I'm not going to speak for KB (he doesn't even know who I am)... but I imagine he was referring the major version upgrade method Red Hat is promoting with RHEL7.  Fedora made FedUp and it has been in use for a few Fedora releases.  Red Hat has basically adapted preupgrade and fedup and greatly expanded them.  They even put a blurb about it in the RHEL 7 Installation Guide.  

See: https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Installation_Guide/chap-upgrading-your-current-system.html

That refers to a RH Knowledgebase article (customer portal account needed to read):

https://access.redhat.com/site/solutions/637583

I believe accounts are free so those without accounts, you might consider giving it a shot and signing up.  I have an account so I'm able to read it.  Here's a tiny bit of the overview portion:

"Red Hat Enterprise Linux 7 (RHEL 7) is the first major release of RHEL to allow in-place upgrades from the previous RHEL major release (RHEL 6). An in-place upgrade offers a way of upgrading a system to a new major release of Red Hat Enterprise Linux without removing the existing operating system."

In a nutshell you use have to be current / all updated (you are, aren't you?), running the 64bit version (since there isn't a 32bit RHEL7), hopefully you don't have a ton of packages... and no third-party repo stuff (if so, get rid of that stuff for the upgrade process and add it back after)... then install preupgrade-assistant.  preupgrade-assistant (preupg) is a several step process (greatly enhanced beyond Fedora)... and if everything looks good (they have reporting tool with several output options)... then you can give the redhat-upgrade-tool a try.

I'm sure CentOS will have to examine that whole major-upgrade-ball-of-fun for redhat-isms... but I'm guessing the process adapted to upgrade CentOS as well as it upgrades RHEL. I tried it once or twice on Fedora and there really were a number of factors that could make it hit or miss... and I haven't even tried it on RHEL yet... and not sure I ever will.  With Fedora I preferred clean installs over upgrades because I know my systems well enough where a clean install and a data restore is much faster than all of the work involved in the upgrade process.  YMMV.

I see people asking questions on this list like... huh... why is xfs the default filesystem in EL7?  And now someone didn't know about the upgrade tool that's all new in EL7.  Red Hat always releases a ton of documentation and this release is certainly no exception.  They actually added a handful of new guides so check them out.  At the very least everyone interested in helping with CentOS 7 building / development should look at the release notes, don't'cha thinK?

See everything here:

https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/

Unfortunately they don't seem to have the html-single option anymore... where you could show a whole guide as a single HTML page with your browser find function being very helpful (CONTROL-f in Firefox anyway).  They still offer html (page-by-page) and PDF.  Maybe they'll add html-single back in the future?  I've been chugging away threw the documentation and I have a ways to go... and a lot of it is review for me since I'm a hardcore Fedora user... but wow... there is a TON of fantastic documentation just begging to be consumed.  Knowledge is power, eh? :)

TYL,
-- 
Scott Dowdle
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