On 9/29/21 3:24 PM, Gestió Servidors wrote:
Hi,
I'm doing some tests of upgrading CentOS from 7 to 8 reading this step-by-step guide: https://netshopisp.medium.com/how-to-upgrade-linux-servecentos-7-to-centos-8...
I'm trying this upgrade in a VM, so I can save "snapshots" and restart in a past saved point. However, all my test ends wrong, exacly in Step 4 when I run "rpm -e `rpm -q kernel`". Then, systems says that some packages are kernel dependencies. After I remove that dependencies, I can't remove kernel...
One problem which could show up here is that kernel packages have changed/splitted and therefore things are more complicated. At least that's what has happened in the past, don't know about 7->8.
That specific step is probably useless. Installing new kernels for Centos8 will sooner or later remove older kernels coming form C7. If you really want to do this manually you could specify the version on your "rpm -e" command.
If you are not ready to tweak the process a bit while upgrading and just expect a straightforward list of commands, well, as others have explained, there is no guaranteed script or method. If instead you have enough familiarity with the system to work around the obstacles, "impossible" things can often be done: for example, years ago I've managed to upgrade a Fedora 16 from i386 to x86_64, and everybody was swearing it was impossible to do.
I can confirm that because I also migrated a server from i386 to x86_64 in place. That was with an old RHEL release.
I don't remember exactly how I did it but I think I only used rpm for it, no yum.
Unfortunately upgrading complex systems is still a lot of work these days, no matter what all the cloud experts try to tell you :-)
Simon