RHEL as a replacement for CentOS?

Issues related to applications and software problems and general support
username
Posts: 72
Joined: 2013/03/04 13:17:23

Re: RHEL as a replacement for CentOS?

Post by username » 2021/02/02 11:33:14

AlmaLinux (CloudLinux team) released a beta of its RHEL clone today : https://blog.almalinux.org/introducing- ... or-centos/

I had a look at RHEL Developper Program yesterday (the 16 free subscriptions for production servers) and their website is quite confusing, to say the least. The conversion from CentOS to RHEL seems to be way more complicated than the ones for Oracle and Springdale.

I guess I will work on finishing the containerization of my product (almost done, apart from the letsencrypt autorenewal from inside a container) and test it on Debian. I have few servers, if the migration script to the chosen RHEL clone fails, I will just install Debian and run docker-compose.

username
Posts: 72
Joined: 2013/03/04 13:17:23

Re: RHEL as a replacement for CentOS?

Post by username » 2021/02/12 14:11:35

P.S. : Springdale is not a 100% clone of RHEL

I tried a dystro-sync from a CentOS box for testing :

Code: Select all

Downgrading:
 libselinux 	x86_64		2.9-2.1.module+el8.1.0+3972+45ab4324	sdl8-appstream	161 k
Enabling module streams:
 libselinux-python		2.8                                                                                           
 python27     
 
On Springdale :

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$ sudo dnf list installed | grep selinux
container-selinux.noarch 	2:2.144.0-1.module+el8.3.0+8221+97165c3f   @sdl8-appstream        
libselinux.x86_64		2.9-2.1.module+el8.1.0+3972+45ab4324       @sdl8-appstream    
libselinux-utils.x86_64		2.9-2.1.module+el8.1.0+3972+45ab4324       @sdl8-appstream        
python3-libselinux.x86_64	2.9-2.1.module+el8.1.0+3972+45ab4324       @sdl8-appstream        
rpm-plugin-selinux.x86_64	4.14.3-4.el8                               @sdl8-baseos           
selinux-policy.noarch		3.14.3-54.el8_3.2                          @sdl8-baseos-updates   
selinux-policy-targeted.noarch  3.14.3-54.el8_3.2                          @sdl8-baseos-updates   
On RHEL (and CentOS)

Code: Select all

libselinux.x86_64		2.9-4.el8_3                          @rhel-8-for-x86_64-baseos-rpms
And it fact, it prevents crond of working while it was fine on CentOS... So careful...

EDIT : It seems to be a dnf issue maybe related to the 3rd party Docker repository. Not sure. But the package libselinux.2.9-4.el8_3 exists in Springdale 8.3 repository. My bad...

tunk
Posts: 895
Joined: 2017/02/22 15:08:17

Re: RHEL as a replacement for CentOS?

Post by tunk » 2021/02/12 15:48:04

This is what I get on C8:

Code: Select all

(root):~# dnf list installed | grep selinux
container-selinux.noarch                           2:2.144.0-1.module_el8.3.0+475+c50ce30b           @AppStream   
flatpak-selinux.noarch                             1.6.2-5.el8_3                                     @appstream   
libselinux.x86_64                                  2.9-4.el8_3                                       @BaseOS      
libselinux-utils.x86_64                            2.9-4.el8_3                                       @BaseOS      
python3-libselinux.x86_64                          2.9-4.el8_3                                       @BaseOS      
rpm-plugin-selinux.x86_64                          4.14.3-4.el8                                      @BaseOS      
selinux-policy.noarch                              3.14.3-54.el8_3.2                                 @baseos      
selinux-policy-targeted.noarch                     3.14.3-54.el8_3.2                                 @baseos      

username
Posts: 72
Joined: 2013/03/04 13:17:23

Re: RHEL as a replacement for CentOS?

Post by username » 2021/02/12 16:44:10

These packages exist in Springdale repos but they where downgraded inexplicably during the distro-sync from CentOS to Springdale.

sml
Posts: 221
Joined: 2020/01/17 09:01:44

Re: RHEL as a replacement for CentOS?

Post by sml » 2021/02/12 17:40:46

Somehow, the libselinux version from module libselinux-python gets selected over the standalone libselinux version. The module libselinux-python is Springdale-specific: neither RHEL nor CentOS provide it. Try

Code: Select all

dnf module disable libselinux-python

username
Posts: 72
Joined: 2013/03/04 13:17:23

Re: RHEL as a replacement for CentOS?

Post by username » 2021/02/15 10:34:49

sml wrote:
2021/02/12 17:40:46
Somehow, the libselinux version from module libselinux-python gets selected over the standalone libselinux version. The module libselinux-python is Springdale-specific: neither RHEL nor CentOS provide it. Try

Code: Select all

dnf module disable libselinux-python
Yes, that solved the issue. Thanks !

There is another problem that people who wants to convert a CentOS box to Springdale will eventually face : the UEFI configuration path changes from /boot/efi/EFI/centos to /boot/efi/EFI/redhat.

Upgrading Grub will prevent the server to boot. I had an exclude=grub2* in my dnf.conf (I hate dealing with grub upgrade issues on a server, I don't think it worth it) so everything worked fine at first. But when I wanted to completely replace CentOS packages I faced this problem. I had to use the netboot to reboot. I guess I would have run into troubles at the next kernel update if I hadn't replaced the Grub packages anyway... I will try to copy to /boot/efi/EFI/centos to /boot/efi/EFI/redhat and do a grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg from a rescue distro.

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