[CentOS] upgrading from CentOS 7 to 8

Tue Oct 1 16:59:35 UTC 2019
LAHAYE Olivier <olivier.lahaye at cea.fr>

Your answer has nothing to do with the original question which is related to upgrade method and not condition for reinstalling without loosing data.

Sometimes you need to keep your configuration and want to avoid reconfiguring everything, and reimaging your computer keeping /home is not an option.
Of course having all user files on a separate filesystem helps when reimaging the OS (that what I do as main developer of SystemImager, but in some circumstances, you may want to just upgrade the OS Like you do when you upgrade iOS-12 to iOS-13 or Android-8 to Android-9 without loosing a single bit of configuration.
A mature OS should be able to do upgrade itself without artifacts. MacOS and iOS and now Windows-10 are example of OS that are able to self upgrade from version to version.

Reimaging a computer to perform an upgrade of its OS is just as silly as rebooting a computer to restart a service (that's what windows-10 still do).

That said, the original question is more like: is there a dnf dist-upgrade or similar to what is available on fedora for upgrading centos-7 to centos-8:

$ sudo dnf upgrade --refresh    # Make sur packages are up to date in current OS release and that there are no dependancies issues.
$ sudo dnf install dnf-plugin-system-upgrade    # Add the OS upgrade plugin
$ sudo dnf system-upgrade download --refresh --releasever=30   # example for fedora-29 to 30 
$ sudo dnf system-upgrade reboot

As of writing, dnf-plugin-system-upgrade package is not available in centos-7 and thus this method is not available to upgrade centos-7 to centos-8.


Le 01/10/2019 17:21, « CentOS au nom de mark » <centos-bounces at centos.org au nom de m.roth at 5-cent.us> a écrit :

    KM via CentOS wrote:
    > I searched a bit to see if there is a way to upgrade from CentOS 7
    > directly to CentOS 8.  I found RHEL instructions but not CentOS.  
    > Although they probably should be/would be similar, the instructions I
    > found enable a rhel repository to get the leap command, which I can't
    > seem to do in CentOS.
    > Does anyone know if you can do an upgrade yet.  I know they had been
    > working on it in the past.
    > also - when they say upgrade (for example on the rhel pages), is it in
    > place meaning I can leave my files/data there, or is it strictly a way of
    > installing the OS that is going to wipe out my files?
    Your files - data, home directories, etc, SHOULD NOT BE ON THE SAME
    FILESYSTEM as the o/s: /, /var/, /etc, /usr.
    If you didn't do that (the way M$ does), then you're ok - the o/s can be
    replaced, and it won't hurt anything... just make SURE that you unselect
    the partitions/drives that everything else is on.
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