Migrate from RHEL to Fedora or CentOS?

[lemon8h8ead]

For various reasons, a friend of mine would like to walk away from an x86 RHEL 4 license and consider using Fedora or CentOS instead. No matter what approach is taken, it will be a distraction from business as usual. So, this manager is looking for the "lesser of evils".

There are very few applications installed on the subject server:

• Apache web server + Perl CGI scripts
• Oracle database server

No matter what course of action is taken, I'll help this friend export+backup all of the web configuration files, web objects, Perl CGI scripts, database tables, database DDL scripts, client application source code, and user directory tree contents. Fortunately, this manager maintains good notes and keeps the important items in a couple of trees. Also, an independent backup system receives deltas every night via FTPS after end of day processing. So, this business is in good shape for a migration.

We were curious about doing a conversion to either Fedora or (perhaps) CentOS instead of re-creating the world. We have time. This will probably take place during the last 2 weeks of the year (relatively "dead" time for the business).

Questions:
1 - Is an "upgrade" to Fedora even possible? Been done before?
2 - Would CentOS 5 be a closer fit and, therefore, lower risk?
3 - Or does doing a ground-up make more sense? (That would be my approach if it were MY business.)

Thank you in advance.

[Seve]

( Moved to Linux Chat )

[leigh123linux]

It would be possible to update to CentOS 5 ( it's real easy )

su
rpm -Uvh http://ftp.heanet.ie/pub/centos/5.2/os/i386/CentOS/centos-release-5-2.el5.centos.i386.rpm
yum clean all
yum update

[nick.stumpos]

yes centos is essentially rhel just without the copyrighted graphics etc. the code is the same. fedora is far more bleeding edge. i would recommend centos over fedora for a production server any day of the week

[lemon8h8ead]

Thanks all for the replies.

One last (not so small, perhaps) thing: There is no `yum` on this RHEL4. I don't know why or when yum might have been introduced to RHEL.

If installing centos-release-5-2.el5.centos.i386.rpm "registers" the system with Centos so that running up2date will work, then probably, this code will work just as well:

sudo rpm -Uvh http://ftp.heanet.ie/pub/centos/5.2/...entos.i386.rpm
sudo up2date --nox -u

Or does someone think that I ought to install just `yum` with up2date and do the mass update with yum?

sudo rpm -Uvh http://ftp.heanet.ie/pub/centos/5.2/...entos.i386.rpm
sudo up2date --nox yum
sudo yum update

Of course, if either code set doesn't work, then we have to strongly consider a re-build.

Here is the content of that RPM file:

/etc/issue
/etc/issue.net
/etc/pki/rpm-gpg
/etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5
/etc/pki/rpm-gpg/RPM-GPG-KEY-beta
/etc/redhat-release
/etc/sysconfig/rhn
/etc/sysconfig/rhn/sources
/etc/yum.repos.d
/etc/yum.repos.d/CentOS-Base.repo
/etc/yum.repos.d/CentOS-Media.repo
/usr/share/doc/centos-release-5
/usr/share/doc/centos-release-5/EULA
/usr/share/doc/centos-release-5/GPL
/usr/share/doc/centos-release-5/autorun-template
/usr/share/eula/eula.en_US
/usr/share/firstboot/modules/eula.py
/usr/share/firstboot/modules/eula.pyc
/usr/share/firstboot/modules/eula.pyo

Thanks in advance.

[forkbomb]

Originally Posted by lemon8h8ead

Thanks all for the replies.

One last (not so small, perhaps) thing: There is no `yum` on this RHEL4. I don't know why or when yum might have been introduced to RHEL.

If installing centos-release-5-2.el5.centos.i386.rpm "registers" the system with Centos so that running up2date will work, then probably, this code will work just as well:

sudo rpm -Uvh http://ftp.heanet.ie/pub/centos/5.2/...entos.i386.rpm
sudo up2date --nox -u

Or does someone think that I ought to install just `yum` with up2date and do the mass update with yum?

sudo rpm -Uvh http://ftp.heanet.ie/pub/centos/5.2/...entos.i386.rpm
sudo up2date --nox yum
sudo yum update

Are you talking about "upgrading" from RHEL4 to CentOS 5? I've not used RH at all, but I have used CentOS, and it seems that there's too much difference between the two to switch from one to the other without a fresh install.

Is that what you were getting at, Leigh - that you can "upgrade" a running RHEL box to CentOS? Seems far-fetched, but I can be an idiot sometimes.

[NoEffex]

Yeah, if you want the latest packages, get fedora. If you want stability, go CentOS.

[leigh123linux]

Originally Posted by tjvanwyk

Are you talking about "upgrading" from RHEL4 to CentOS 5? I've not used RH at all, but I have used CentOS, and it seems that there's too much difference between the two to switch from one to the other without a fresh install.

Is that what you were getting at, Leigh - that you can "upgrade" a running RHEL box to CentOS? Seems far-fetched, but I can be an idiot sometimes.

RHEL & CentOS are basically the same OS so the update should be easy .

[leigh123linux]

Originally Posted by lemon8h8ead

Thanks all for the replies.

One last (not so small, perhaps) thing: There is no `yum` on this RHEL4. I don't know why or when yum might have been introduced to RHEL.

If installing centos-release-5-2.el5.centos.i386.rpm "registers" the system with Centos so that running up2date will work, then probably, this code will work just as well:

sudo rpm -Uvh http://ftp.heanet.ie/pub/centos/5.2/...entos.i386.rpm
sudo up2date --nox -u

Or does someone think that I ought to install just `yum` with up2date and do the mass update with yum?

sudo rpm -Uvh http://ftp.heanet.ie/pub/centos/5.2/...entos.i386.rpm
sudo up2date --nox yum
sudo yum update

Of course, if either code set doesn't work, then we have to strongly consider a re-build.

Here is the content of that RPM file:

/etc/issue
/etc/issue.net
/etc/pki/rpm-gpg
/etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5
/etc/pki/rpm-gpg/RPM-GPG-KEY-beta
/etc/redhat-release
/etc/sysconfig/rhn
/etc/sysconfig/rhn/sources
/etc/yum.repos.d
/etc/yum.repos.d/CentOS-Base.repo
/etc/yum.repos.d/CentOS-Media.repo
/usr/share/doc/centos-release-5
/usr/share/doc/centos-release-5/EULA
/usr/share/doc/centos-release-5/GPL
/usr/share/doc/centos-release-5/autorun-template
/usr/share/eula/eula.en_US
/usr/share/firstboot/modules/eula.py
/usr/share/firstboot/modules/eula.pyc
/usr/share/firstboot/modules/eula.pyo

Thanks in advance.

I would use yum to update .

[Evil_Bert]

RHEL and CentOS packages are allegedly interchangeable - in most cases they're compiled from exactly the same source, so they should be. Here, though, you're upgrading from one major release to the next, so there's risk of breaking something. From what I've read on the web, CentOS <5.0 can't be upgraded successfully to CentOS 5.x due to too many interdependencies .... but there may be fixes.

It would be interesting to see if it worked. If willing to try, I would:
a. get yum (any version)
b. install the CentOS 5.2 release rpm
c. check CentOS 5.2 is your only enabled repo (just in case)
d. update yum separately:

yum update yum

e. then upgrade the rest of the system:

yum upgrade

I'd also be prepared to do a fresh install if the above fails.

Here are a couple of sites with useful advice:
http://www.cyberciti.biz/tips/upgrad...-51-to-52.html
http://www.silfreed.net/content/centos-upgrade-success

Edit: Even though we normally accept that yum upgrade and yum update now do exactly the same thing (due to obsoletes=1 being set in yum.conf), if you're getting yum from CentOS, I don't know what the default setting in yum.conf will be, hence the suggestion of yum upgrade. Alternatively, you could use yum update --obsoletes.

[Evil_Bert]

Originally Posted by lemon8h8ead

... this manager is looking for the "lesser of evils" ...

Having thought about it a bit more ...

Have you considered jus changing to CentOS 4.x? CentOS 4 will remain supported until Feb, 2012, which will give you time to consider other measures - you may even plan on replacing hardware in that timeframe or moving to a virtualised server, in which case, you'd need to do a fresh install then, anyway. So changing to CentOS 4.x may give you what you want now with minimum pain.

Changing from RHEL 4.x to CentOS 4.x seems to be relatively routine. Here's one guide:
Converting RHEL 4 to CentOS 4.

[SlowJet]

Download the CentOS 5.2 dvd and do a proper upgrade.


SJ

[lemon8h8ead]

I followed the following procedure verbatim and it worked like a charm:

http://www.cse.ucsd.edu/deptadmin/cs...o_centos4.html

Thank you, Evil Bert.

It turns out someone at UCSD had developed a shell script to automate the process (at the bottom of http://www.cse.ucsd.edu/deptadmin/cs..._overview.html). I did the manual procedure which did not take very long.

Thanks also to everyone else for the other comments.

[Evil_Bert]

Originally Posted by lemon8h8ead

Thank you, Evil Bert.

You're welcome. We like to see satisfied customers.

(Maybe now is a good time to ask the Admin's for that raise ..... )