CentOS Migration Overview

In December 2020, Red Hat announced the transformation of CentOS from a downstream rebuild of RHEL into an upstream development branch (CentOS Stream). This means that traditional CentOS no longer provides a 1:1 RHEL-compatible stable release.

• CentOS 7 — Reached end of life (EOL) on June 30, 2024
• CentOS 8 — Reached end of life (EOL) on December 31, 2021
• CentOS Stream — Continues to exist, but is now positioned as an upstream for RHEL

If you are running CentOS 7 or CentOS 8, you must migrate to a supported distribution.

Choosing a Migration Target

AlmaLinux

• Initiated and funded by CloudLinux, Inc.
• Provides the official migration tool almalinux-deploy
• Migrates EL8.4+ (Alma/Rocky/Oracle/Stream 8) to AlmaLinux; CentOS 7 cannot go directly (the script requires EL8.4+), upgrade to EL8 with ELevate first
• Detailed migration steps →

Rocky Linux

• Initiated by a CentOS co-founder
• Provides the official migration tool migrate2rocky
• Supports migration from CentOS 8 and other EL versions
• Detailed migration steps →

Other Migration Targets

In addition to AlmaLinux and Rocky Linux, you may also consider:

Target	Suitable Scenarios	Migration Method
Oracle Linux	Oracle database environments, need for UEK kernel	migrate-to-oracle-linux.sh (oracle/migrate-to-ol, community-maintained script)
Anolis OS	Alibaba Cloud environments, domestic OS requirements	Requires redeployment or refer to Anolis migration documentation
OpenCloudOS	Tencent Cloud environments, domestic IT requirements	Requires redeployment or refer to OpenCloudOS documentation
RHEL	Need commercial support	Red Hat offers free developer subscriptions (16 machines)

Tip

From a feature standpoint, AlmaLinux and Rocky Linux are nearly identical and are the most popular migration targets. Oracle Linux is suited for specific use cases. Users in China who are heavily invested in Alibaba Cloud or Tencent Cloud may also consider Anolis OS or OpenCloudOS.

Important Pre-Migration Preparations

Regardless of which distribution you are migrating to, you should complete the following preparations first:

1. Full backup — Including system configuration, databases, and application data
2. Document the current environment — Installed package list, running services, network configuration, cron jobs
3. Validate in a test environment — Complete a full migration in a test environment first
4. Notify stakeholders — Schedule a maintenance window and inform relevant parties
5. Prepare a rollback plan — Ensure you have snapshots or backups to revert to

Back up the list of installed packages

$ rpm -qa --queryformat '%{NAME}\n' | sort > ~/installed-packages.txt

Back up the list of running services

$ systemctl list-units --type=service --state=running > ~/running-services.txt

Back up network configuration

$ nmcli connection show > ~/network-connections.txt

Migration Paths

Current System	→ AlmaLinux	→ Rocky Linux	→ Oracle Linux
CentOS 7	Supported (ELevate -> AlmaLinux 8)	❌ No official path (ELevate has no leapp-data-rocky)	Community script, not official
CentOS 8	Supported	Supported	Supported
CentOS Stream 8	Supported	Supported	Supported
CentOS Stream 9	Supported	Supported	Supported
Oracle Linux	Supported	Supported	—
AlmaLinux	—	Supported	Supported
Rocky Linux	Supported	—	Supported

Next Steps

• Migrate to AlmaLinux — Using the almalinux-deploy tool
• Migrate to Rocky Linux — Using the migrate2rocky tool
• Post-Migration Checklist — Verification steps after migration
• Distribution Overview — Compare all EL distributions