How to migrate from CentOS 8 to AlmaLinux (conversion)

I already wrote about migrating from CentOS 8 to Rocky Linux. Today, this quick post will list steps to convert existing VM or bare metal server from CentOS 8 to AlmaLinux 8.

WARNING! Make a backup before you start upgrading and the conversion procedure. I am an experienced Linux user, developer and sysadmin. However, there is no substitute for backups. Keep verified backups. Do not proceed further without backups. CyburDial is not responsible for data loss.

If you are doing this over an SSH session, I recommend running commands over GNU/screen or Tmux terminal multiplexer.

Migrating from CentOS 8 to AlmaLinux (conversion)

1. Log in as the root user:
   sudo -i
2. Apply pending updates to CentOS 8 by running the dnf command/yum command:
   dnf update

• Apply pending updates before migration starts
• Reboot the Linux box when new kernel updates are installed:
  reboot
• After reboot, you need to download the almalinux-deploy.sh script using the wget or curl command, type:
  wget https://raw.githubusercontent.com/AlmaLinux/almalinux-deploy/master/almalinux-deploy.sh
# read the script #
vim almalinux-deploy.sh
• Next set up executable permission using the chmod command, run:
• chmod -v +x almalinux-deploy.sh

• Downloading almalinux-deploy.sh script
• Finally, migrate CentOS to AlmaLinux by typing the almalinux-deploy.sh:
  ./almalinux-deploy.sh
• 
• AlmaLinux migration tool in action
• The upgrade and migration will take their own sweet time. It all depends upon your server hardware specification and the Internet speed. So wait and watch for errors on the screen. In the end, you should see a confirmation message as follows on screen:Complete! Run dnf distro-sync -y OK Restoring of alternatives is done OK Generating grub configuration file … done All Secure Boot related packages which were released by not AlmaLinux are reinstalledOK   Migration to AlmaLinux is completed
• Reboot the Linux box hosted at AWS or Linode:
  shutdown -r now
Connection to 3.1x.2xx.2xx closed by remote host.
• Finally, verify the AlmaLinux version, run: cat /etc/redhat-release
## OR ##
cat /etc/os-release

• CentOS to Almalinux migration successfully executed
• Also, make sure all services such as PGSQL, Apache and others are running using the ps command or ss command:
  ss -tulpn | more
ss -tulpn | grep ":80"
# Verify logs using the tail command and dmesg command+egrep command #
tail -f /var/log/httpd/app_name_goes_here
dmesg | egrep -i 'error|critical|warn'

This will convert your centos8 system over to AlmaLinux

Last step is to recompile dahdi:

cd /usr/src/dahdi-linux-complete-3.1.0+3.1.0/

make && make install

modprobe dahdi

dahdi_cfg -v (to check no errors)

I hope this helps

-Carpenox aka Chris