Upgrading from 6.10

[lbon]

Wanted to write in the CentOS6 groups, but they are now read only as no one should use them any longer.

Well... we use them, and we would like to use the CentOS installations that we have for so long as we can. They run in a VMware esx 7 environment.

I guess that it would be best to run CentOS7 as this is supported officially on ESX7 and ESX8 (CentOS 6 and 8 only supported "Legacy")

I know CentOS 7 has end of life 2024... but being able to run CentOS for one more year is ok.

Now to the issue. I read different reg. upgrading from 6 to 7... most says this is not possible at all... others has guidelines on how to actually do it... but it does not work for me.

Has anyone successfully upgraded frem 6.10 to 7 in anyway - and if so: how?

Regards, Lars.

[TrevorH]

There is no upgrade path from one CentOS major version to another. It's a re-install. And since CentOS 7 goes EOL in about 10 months, I would recommend looking at alternatives. All of Rocky, Alma and Oracle Enterprise Linux attempt to build clones of RHEL in the same way that CentOS did and produce RHEL-alike 8 and 9 distros. You could look at one of those as a replacement. Or you could move to something entirely different without the Red Hat drama like Debian.

It's not worth exchanging one EOL distro for one that only has 10 months of life left. Look at moving to something that will last you a good long while.

CentOS is dead.

[lbon]

I understand that CentOS is dead... But if I can squeeze a little life out from it even if only 10 months in a fairly easy way, I would be ok with it. Like if I can do an in place upgrade, which some people claims should be possible.

Although I haven't succeeded doing that yet... Maybe because it really isn't possible...

[TrevorH]

The problem is that 6 to 7 is the version change where a lot changed. 7 has systemd, 6 does not. Once you go from 7 on it's more similar so really, 9 is not that much different to 7 except that it's 8 or 9 years newer (though there are significant differences like no network scripts so it's NetworkManager or nothing).

The spirit of CentOS lives on though in Rocky and Alma Linuxes so those are where I would head if you want a version of CentOS. That's where CentOS has gone even though it has left the name behind (because it belongs to Red Hat).

[Whoever]

no network scripts so it's NetworkManager or nothing).

Who thought this was a good idea? My personal opinion is that anything beyond a very simple network setup is much simpler using the scripts and ifcfg-* files than NetworkManager. For example, setting up a bridge on a bonded pair of interfaces.

[jlehtone]

Each RHEL major version is a distinct distro, years apart. Yes, they are similar, but what isn't?

What does one have in a system?

• List of installed packages
• Configuration for those programs (including uid's, gid's, and co.)
• User data, (in /home/*, /var/www, and so forth)

One should always have a backup of the data and some restorable copy of the config.
An existing system can become inaccessible for many reasons, and then you have to install&restore.

If one can install&restore, particularly in easy way, then install of a new distro should be trivial.
Granted, the list of packages and config related to them has to be adjusted.

My personal opinion is that anything beyond a very simple network setup is much simpler using the scripts and ifcfg-* files than NetworkManager. For example, setting up a bridge on a bonded pair of interfaces.

If you know how to edit files or how to use NetworkManager's tools, then yes, things are "simple". (If one don't know, then nothing is.)

There is however a new kid in the block that Red Hat is promoting (with documentation): RHEL System Roles for Ansible. (Upstream has Linux System Roles.)

There is "network" system role too, with which you can decide config (including bridges on VLANs via bond) for every machine in one text (YAML) file (that does not have to be in any of them). The role knows how to talk to both NetworkManager and initscripts (or whatever EL6-EL9 or Fedora 16- do have), so you don't have to. (Alas, latest Ansible no longer accepts Python that EL6 had, but dead are better left dead?)

Granted, the system role does not support every feature of NetworkManager and NetworkManager does not support every feature of Linux kernel, but adding tasks to Ansible play to tie those loose ends is "simple" too.

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As I see it, one can try to tamper with the CentOS 6 install for quite some time and in best case scenario be able to run chimera of el7 for couple months, or one could focus on getting backups and description of the desired config and then install a fresh system, be it el7, el8, el9, or something else. (The el9 requires that the CPU supports x86_64-v2 features.)