[CentOS] Upgrading CentOS from 7 to 8

Wed Sep 29 13:56:05 UTC 2021
Valeri Galtsev <galtsev at kicp.uchicago.edu>

On 9/29/21 8:29 AM, J Martin Rushton via CentOS wrote:
> It's not supported.  RH has a method that sometimes works for RHEL, but 
> there is no safe CentOS way to do a major upgrade.  You need to 
> reinstall the OS and migrate your applications.

+1 The system "binary clone" of which CentOS is (or was rather) is not 
designed to be "upgraded". The routine way is: install new release, copy 
all accounts, and data from old system to it, install services, 
configure them to a degree possible close to what was on old system.

This horse have been beaten to death. The problem someone asking this is 
a consequence it people not doing search first (I for one use 
duckduckgo), and reading all search reveals with open eyes, not picking 
something to one's liking. Like: I want to do an upgrade. No matter all 
search shows is: "install new release,...". I did find one post about 
upgrade. But why it doesn't work?! Just read any of other posts about 
upgrade, saying to the effect: it doesn't, shouldn't work, and going 
into various lengts of explaining why.

I know what I said doesn't make pleasant reading, but it hopefully will 
help someone with "modus operandi".


> On 29/09/2021 14:24, 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-ec2db96a189b 
>> 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...
>> Anybody has tested process upgrade from 7 to 8?
>> Thanks.
>> _______________________________________________
>> CentOS mailing list
>> CentOS at centos.org
>> https://lists.centos.org/mailman/listinfo/centos

Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247