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Once you go CentOS, is it possible to go back?

Posted: 2005/03/04 18:22:21
by bobjunga
I have new server I am installing RHEL4 on today. I am deciding whether to try CentOS for updates or buy a RHN subscription. If I use update from CentOS, will I still be able to switch back and get a RHN subscription on this machine at some point in the futire if I want? Or will the CentOS updates change some things on the mahine so that RHN won't recognize it as RHEL anymore?


BTW, the 'submit' button for changing the 'form type' on the top of the new post form is unfortunatly named. If you click on it thinking you are subbmitting your form, you actually reset the form and loose the message you typed. Maybe "chnage format" would be a better name.

Once you go CentOS, is it possible to go back?

Posted: 2005/03/04 21:07:41
by tarponbill
I have a similar question --- can I switch to centos 4 after installing RH AS4.

DO I just download atp-get or how would I do it?

Can the process then be reversed and go back to RH AS RHN support?

I guess the bottom line is how switchable is the RH and centos distributions?

If someone can tell me how I would be willing to try it out on a test system.

Re: Once you go CentOS, is it possible to go back?

Posted: 2005/03/05 05:28:22
by stevecoh1
I'm no expert, and the experts can no doubt chime in, but let me give you my experience in going the other way.

I downloaded CentOS ISOs. I then followed the Owl River RH9->Centos guide. All I did was mount the ISO images, and pulled in all the upgrade RPMs with yum. I had get rid of a few RPMs that I didn't really need anyway, which weren't compatible, as Yum told me. Then I ran Yum again. When I was done, and rebooted, I was running CentOS I can't imagine why you couldn't take some hypothetical future RedHat ISOs and do the same thing the other way, especially since CentOS seems to be quite explicitly saying, at least for now, that their policy is NOT to do any value-adds on top of RedHat.

It isn't that you're "reversing" the process, you'd be installing RedHat ISOs over CentOS.

Re: Once you go CentOS, is it possible to go back?

Posted: 2005/03/22 17:32:40
by jmalcolm
I would say that you are correct but I remember that RPM will only want to change packages if they are upgrades. So, you could install a future version of RHEL on top of CentOS 4 as easily as you could install that version over RHEL4. However, trying to install RHEL4 over CentOS 4 would be like installing RHEL4 over RHEL4. It is not really an upgrade.

I would say that you should have very little trouble installing RHEL4 updates from RHN over CentOS 4 as well. If Red Hat is checking the release number it is most likely via the /etc/redhat-release file. If you replace the centos-release RPM with the redhat-release RPM from RHEL4 I bet that Red Hat sees your system as RHEL4 for the purpose of updates. You could at the very least install them manually.