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still under construction. If you need assistance, please use centos
mailing lists Welcome to the CentOS-2 Migration Centre
CentOSCentOS 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-2CentOS-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-3.1CentOS-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:
Migrating to CentOSDepending 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 DistributionThis procedure normally requires the following steps:
Benefits
Drawbacks
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 upgradeThis procedure normally requires the following steps:
Benefits
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Errata SupportThis procedure normally requires the following steps:
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Migration MatrixRHL = Red Hat Linux
Whitebox & Tao? Procedures Red Hat Enterprise Linux 2.1 AS/ES/WS x86 Live Errata Update to CentOS-2rpm --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-2Install 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 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 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 Before you reboot into your new kernel you might want to complete the package downgrades sh ./check_packages_centos2.sh
--combine > 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 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.
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