This was my experience with upgrading, your mileage may vary especially if it's in kilometers. This is what I had to do to get my system running again.
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In order to attempt this upgrade, I had to use "linux upgradeany", a mode not listed for the installer CDs.
My first problem was I could no longer boot the system after the upgrade. My grub menu showed my old FC2 kernel, Fedora Core (2.6.10-1.14_FC2), but not the kernel for Centos. Trying to boot this FC2 kernel it froze after "Enabling swap space:"
* Boot up the "linux rescue", chroot /mnt/sysimage * used lynx to download kernel-2.6.9-5.EL.i686.rpm * rpm -ivh kernel-2.6.9-5.EL.i686.rpm
warning: kernel-2.6.9-5.EL.i686.rpm: V3 DSA signature: NOKEY, key ID 4fe06303 error: failed to stat /dev/shm: No such file or directory Preparing... ################################################## package kernel-2.6.10-1.14_FC2 (which is newer than kernel-2.6.9-5.EL) is already installed
* rpm -ivh --old-package kernel-2.6.9-5.EL.i686.rpm
warning: kernel-2.6.9-5.EL.i686.rpm: V3 DSA signature: NOKEY, key ID 4fe06303 error: failed to stat /dev/shm: No such file or directory Preparing... ################################################## error: %pre(kernel-2.6.9-5.EL.i686) scriptlet failed, exit status 255 error: install: %pre scriptlet failed (2), skipping kernel-2.6.9-5.EL
* rpm2cpio kernel-2.6.9-5.EL.i686.rpm | cpio -i --make-directories * mv boot/* /boot/ * mv lib/modules/* /lib/modules/ * depmod -a * mkinitrd /boot/initrd-2.6.9-5.EL 2.6.9-5.EL * edit /etc/grub.conf an add in this kernel
* rebooted into the Centos-4 system at this point just need to do some finishing work to get things started
* fedora-release-2-4.i386 wasn't upgraded to centos-release
* yum wouldn't run as the fedora release version was 2 cp /etc/yum.conf /etc/yum.conf.old cp /etc/yum.conf.rpmnew /etc/yum.conf
wget http://beta.centos.org/centos/4.0beta/os/i386/CentOS/RPMS/centos-release-4.0...
rpm -e --nodeps fedora-release rpm -ivh centos-release-4.0beta-5.i386.rpm rpm --import /usr/share/rhn/RPM-GPG-KEY-centos4.0beta yum clean all rpm -e --nodeps $(rpm -qa | grep kernel | grep FC2) yum install kernel (or rpm -ivh kernel-2.6.9-5.EL.i686.rpm) yum update
-Mike