Migrating from CentOS to AlmaLinux or Rocky Linux

Why Migrate?

CentOS Linux 8 reached end of life in December 2021, and CentOS 7 followed in June 2024. AlmaLinux and Rocky Linux are community-driven, RHEL-compatible replacements that provide the same stability and ecosystem you relied on with CentOS.

Choosing Between AlmaLinux and Rocky Linux

• AlmaLinux — backed by CloudLinux, strong hosting industry support, offers the ALBS build system
• Rocky Linux — founded by CentOS co-founder Gregory Kurtzer, aims to be a direct CentOS replacement

Both are excellent choices and fully binary-compatible with RHEL.

Pre-Migration Steps

# Take a snapshot of your Breeze before migrating
# Document installed packages
rpm -qa > /root/installed-packages.txt

# Back up critical configs
tar czf /root/config-backup.tar.gz /etc/nginx /etc/my.cnf.d /etc/php* /etc/sysconfig

Migrate to AlmaLinux

curl -O https://raw.githubusercontent.com/AlmaLinux/almalinux-deploy/master/almalinux-deploy.sh
sudo bash almalinux-deploy.sh
sudo reboot

Migrate to Rocky Linux

curl -O https://raw.githubusercontent.com/rocky-linux/rocky-tools/master/migrate2rocky/migrate2rocky.sh
sudo bash migrate2rocky.sh -r
sudo reboot

Post-Migration Verification

# Confirm OS release
cat /etc/os-release

# Rebuild rpm database
sudo rpm --rebuilddb

# Check for broken packages
sudo dnf check

# Update all packages
sudo dnf update -y

Post-Migration Checklist

• Verify all services start correctly: systemctl list-units --failed
• Test web server, database, and application functionality
• Confirm firewall rules are intact
• Re-run any configuration management or automation tools
• Update monitoring to reflect the new OS