[CentOS] Upgrading to CentOS 7

[Jim Perrin]

On 05/19/2015 09:12 AM, Timothy Murphy wrote:
> Johnny Hughes wrote:
> 
>> On 05/19/2015 07:43 AM, Timothy Murphy wrote:
>>> I read in <http://wiki.centos.org/TipsAndTricks/CentOSUpgradeTool>
>>>
>>> "Warning: use of this tool is currently not recommended as several
>>> system- critical packages are of a higher version number in CentOS 6.6
>>> than they are in CentOS 7 so those do not get upgraded correctly. This
>>> renders yum and several other system tools non-functional."
>>>
>>> Does this still hold?
>>> It seems to me a bit pointless to offer a tool
>>> with the warning that it does not work.
> 
>> It is not pointless, some people want to do it.
>>
>> I would not use it.
> 
> First of all, thank you very much, Johnny, for all your work.
> You are doing a fantastic job.
> 
> However, I find your answer here a little odd.
> It's a bit like the surgeon saying, "I wouldn't have this operation,
> but if you want it just lie back."
> 

That's not far from the truth. Upstream, this tool supports a very
limited scope, and has a rather substantial pre-upgrade test to
determine how feasible it is. Since we don't differentiate between
Server, Workstation, etc it's a bit more interesting for us to say "yeah
sure you can totally run this". If you add 3rd party packages into the
mix, it gets even crazier.

>> The best way to do any major update is to backup your data, install the
>> OS, bring back your data and make all the newer services (if you are
>> moving things like databases or web directories, etc.).
>>
>> Some people want to take shortcuts to this procedure, and with enough
>> effort, that tool can work.  But to me, there is too much effort and
>> there are too many older packages left around as clutter, so I would
>> never do it.
> 
> If it would take you a lot of time and effort to clean up after the upgrade
> I can't imagine how long it would take me.

If you have a good config management environment set up, rolling out a
new build to replace older systems is much easier than walking through
an update on each system. I really recommend people use ansible, chef,
puppet.. whatever they're comfortable with to do some basic automation.


>> Red Hat released this, so we rebuilt it .. that does not mean one should
>> use it.
> 
> Strange.

It's a feature people have wanted/demanded for years. It doesn't make it
sane, just popular.



-- 
Jim Perrin
The CentOS Project | http://www.centos.org
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