CentOS-2 Enterprise Linux 2.1AS
Maintained by John Newbigin

Warning: This page is still under construction.  If you need assistance, please use centos mailing lists

Welcome to the CentOS-2 Migration Centre

cAos is a community of open source contributors and users focused on producing enterprise-level, community-produced and managed Linux solutions.

CentOS

CentOS is designed specifically to be as close to Red Hat Enterprise Linux as possible but without trademark restrictions.  The Red Hat guidelines for trademark removal have been followed and some other references to Red Hat have been removed.  CentOS is functionally identical to Red Hat Enterprise Linux.

CentOS-2

CentOS-2 is the free version of Red Hat Enterprise Linux 2.1AS.  There is no ES or WS versions because these are functional subsets of AS.  Because CentOS is free as in beer, there is no need to use a cut down version.  Red Hat release updates to their Enterprise Linux 2.1 every 3 months.  These updates are just a collection of errata and do not constitute a version number increase.  Currently the only available version of CentOS-2 is final.  That version contains a number of errata over the original Red Hat release but there have been a large number of errata since that release.  There may be an update of CentOS-2 released in the future but it will likely not be any different to installing final and all the available errata.

CentOS-3.1

CentOS-3.1 is the free version of Red Hat Enterprise Linux 3AS.  There is no ES or WS versions because there are functional subsets of AS.  Because CentOS is free as in beer, there is no need to use a cut down version.  Red Hat release updates to their Enterprise Linux 3 every 3 months.  These updates are just a collection of errata but are treated as minor version number increases for CentOS-3 numbering. xxxx what is the new version???

This table shows a summary of the cAos Foundation distributions:

Distribution CentOS-2 CentOS-3.1 cAos 1.0 cAos 2.0
Community Composed No No Yes Yes
Community Built Yes Yes Yes Yes
Community Supported Yes Yes Yes Yes
Free as in Speech Yes Yes Yes Yes
Free as in Beer Yes Yes Yes Yes
Financial Donation Requested Yes Yes Yes Yes
Operating System Base RHEL 2.1 RHEL 3 CentOS-2 CentOS-3/Custom

 

Migrating to CentOS

Depending on what linux distribution you are currently running and what distribution you wish to migrate to, there are a number if methods which may be possible.  These methods are briefly described here:

Install new Distribution

This procedure normally requires the following steps:

  • Backup existing operating system (optional but recommended)

  • Backup existing data and configuration

  • Install new distribution

  • Restore required data and configuration

Benefits

  • Most reliable method

  • Clean install removes legacy software and unsupported 3rd party software

  • Reproducible install

Drawbacks

  • High risk.  Aborting the upgrade requires restoration of original operating system and data

Other techniques

If extra hardware is available then the new installation can be done without impacting the existing system.  Data and configuration can then be copied at leisure.  At any time the original system is available so the procedure can be aborted.  After the upgrade the old system is still available for instant access to potentially missing configuration etc.

Live upgrade

This procedure normally requires the following steps:

  • Backup existing operating system

  • Backup existing data and configuration

  • Upgrade all packages to new distribution

Benefits

  • No need to reinstall and restore data from backups

  • Configuration can be migrated

Drawbacks

  • High risk

  • High failure rate

  • Configuration may not be compatible

  • Not normally supported

  • Requires extra disk space?

Errata Support

This procedure normally requires the following steps:

  • Install new update tools

  • Uninstall software which is not longer licensed

Benefits

  • No reinstallation

  • No backups

  • Revertible

Drawbacks

  • Operating System will contain a mixture of vendors

 

Migration Matrix

RHL = Red Hat Linux
RHEL = Red Hat Enterprise Linux

Arch Current Distro Procedure New Distro Notes
x86 RHL 7.2 Install CentOS-2
Live CentOS-2 untested
RHL 7.3 Install CentOS-2 Package downgrades?
RHL 8 Install CentOS-3 Binary compatibility?
RHL 9 Install CentOS-3
RHEL 2.1AS
RHEL 2.1ES
RHEL 2.1WS
Install CentOS-2 100% compatible
Live CentOS-2 Required?
Errata CentOS-2
RHEL 3 Install CentOS-3
Live CentOS-3
Errata CentOS-3
itanium
AMD64/
EM64T
iSeries/
pSeries
zSeries/
S/390

Whitebox & Tao?

Procedures

Red Hat Enterprise Linux 2.1 AS/ES/WS x86 Live Errata Update to CentOS-2

rpm --test --erase up2date up2date-gnome rhn_register rhn_register-gnome

rpm -ivh http://mirror.centos.org/centos-2/final/i386/CentOS/RPMS/yum-1.0.3-1_73.noarch.rpm

Edit /etc/yum.conf to select appropriate mirror.  You only need the [base] and [updates] sections.

export http_proxy=http://myproxy:8000/

run yum upgrade

Yum will download the headers and so some churning for a while.  When prompted enter y

After a while you should get the message Transaction(s) Complete.  This means all centos branded upgrades have completed.

Sideways releases.  These are packages which make your machine appear like a centos box rather than a redhat box.  The package names are different so yum can't do this on it's own.  This step is optional but recommended.

rpm --erase redhat-release-ws redhat-release-es redhat-release-as; yum install centos-release-as

You will only have one of these packages installed so rpm will print a warning but you can safely ignore that.

rpm --erase redhat-logos --nodeps; yum install centos-logos

If you want to restore a working rpmdb-redhat (because redhat ship broken updates)

rpm --erase rpmdb-redhat; yum install rpmdb-redhat

Join xxx@centos.org mailling list. When errata are released, just run yum update

 

Red Hat 7.2 Live Upgrade to CentOS-2

Install Red Hat 7.2

Apply all available patches from Red Hat (and Progeny if available)

Clean up .rpmnew & .rpmsave files to prevent confusion later. (locate is your friend)

make a boot disk just in case. mkbootdisk `uname -r`

You will need around 250Meg of free disk space under /var/cache/yum to upgrade a typical install.  If you have a complete install this might be more.  If you want, now is a good time to make /var/cache/yum a symlink to another disk.

If you are using lilo as your boot loader it is probably a good idea to switch to grub.  The kernel rpms will automatically update the grub config file.  If you use lilo you will have to maintain the config and run lilo manually.  <instructions on installing grub...>

Install yum for CentOS-2

rpm -ivh http://mirror.centos.org/centos-2/final/i386/CentOS/RPMS/yum-1.0.3-1_73.noarch.rpm

Edit /etc/yum.conf to select appropriate mirror.  You only need the [base] and [updates] sections.

run yum upgrade

Yum will download the headers and so some churning for a while.  When prompted enter y

After a (long) while you should get the message Transaction(s) Complete.  This means all the upgrades have completed.  You might want to run yum upgrade again to make sure.  There should be nothing left to do the second time.

Once yum has done it's stuff, there are a few more packages which you will need to attend to.

Sideways releases.  These are packages which make your machine appear like a centos box rather than a redhat box.  The package names are different so yum can't do this on it's own.  This step is optional but recommended.

rpm --erase redhat-release; yum install centos-release-as
rpm --erase redhat-logos --nodeps; yum install centos-logos

Downgrades.  Many packages in CentOS-2 are numbered differently to the Red Hat 7.2 versions.  This means a newer version may have a smaller version number.  Yum doesn't like that so I have a bash script which will detect these packages.

Obtain and run check_packages_centos2.sh.  It will recommend some rpm commands to run.  The script is not very smart and you will have to combine packages which have interdependencies like glibc and glibc-common.

wget check_packages_centos2.sh
sh ./check_packages_centos2.sh > todo
vi todo (delete the lines you don't want)
. todo

Note: some users have had better success upgrading to the CentOS-2 glibc before running the yum upgrade.  If you are getting errors then then you might want to try that.  You may also want to upgrade rpm before other packages.

Not all the downgrades will work yet.  You can try using the --combine parameter to the script.  You will still have to edit the resulting rpm command but it will fix most of the problem packages.  For everything else you can rerun the script once you get the new kernel going.

You should install and boot a new kernel before you remove the existing (currently running) kernel.  You might also have to install labaio

yum install labaio
rpm -i http://bender.it.swin.edu.au/centos-2/updates/i686/kernel-2.4.9-e.49.i686.rpm --oldpackage

Before you reboot into your new kernel you might want to complete the package downgrades

sh ./check_packages_centos2.sh --combine > todo
vi todo (delete the lines you don't want (like modutils))
. todo

Reboot.  Assuming everything goes OK in the reboot you will be able to log back in and erase the old kernels

rpm -q kernel
rpm --erase kernel-
<version>

Last step, run yum again to make sure you have all the updates applied.

yum update

issues

Note: When you run rpm with a URL as a parameter, the file is downloaded but is not stored locally.  If the transaction fails and you run the command again the file will be download again.  For local networks that shouldn't be a problem but if you are downloading over the internet you might want to download using wget first and then install from a local file.

 

Family Tree

 

RH50 19971201 Hurricane
RH51 19980601 Manhattan
RH52 19981012 Apollo
RH60 19990419 Hedwig
RH61 19991004 Cartman
RH62 20000327 Zoot
RH70 20000925 Guinness
RH71 20010416 Seawolf
RH72 20011022 Enigma
RH73 20020506 Valhalla
RH80 20020930 Psyche
RH9 20030331 Shrike
FC1 20040305 Yarrow
FC2 20040518 Tettnang
FC3 20041108 Heidelberg

EL21 20020506 Pensacola Panama ?
EL3 20031022 Taroon
EL4 20050201 Nahant

CentOS-2 20040504
CentOS-3.1 20040513
CentOS-4 20050301


Last modified 20050812
Maintained by John Newbigin Home Page