Migrate CentOS 7, CentOS 8 and Rocky Linux to AlmaLinux — Upgrade AlmaLinux 9 to 10

CentOS and Rocky Linux administrators may need to move to AlmaLinux for lifecycle, support, compatibility or standardization reasons. The safe method depends on the installed operating-system version. Do not use one migration command for every scenario: converting a supported Enterprise Linux 8 system is different from upgrading CentOS 7 across several major releases.

1. Pre-migration checklist

Complete these checks before changing repositories or replacing system packages. For remote servers, arrange out-of-band or hypervisor console access rather than relying on a fragile SSH-only session.

Identify the installed distribution and version:

cat /etc/os-release
cat /etc/redhat-release
uname -r
df -h / /boot

2. Migrate CentOS 8 to AlmaLinux using almalinux-deploy

The AlmaLinux migration tool supports CentOS Linux 8 (minimum supported Enterprise Linux 8 version 8.4) and converts supported EL systems to AlmaLinux within the same major version. CentOS Linux 8 is end-of-life, so its standard mirrors may no longer work; consult the official migration guide for Vault/repository recovery instructions if package updates fail.

Step 1 — Update and check prerequisites

sudo dnf update -y
sudo dnf install -y dnf-plugins-core

If dnf update fails because CentOS 8 repositories are unavailable, stop and follow the repository/Vault guidance in the official AlmaLinux migration guide rather than randomly replacing repository files.

Step 2 — Download the official migration script

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

Review the script and confirm it comes from the official AlmaLinux project repository before execution. Ensure the machine has enough free disk space, GRUB2 where required, and stable console access.

Step 3 — Run the conversion

sudo bash almalinux-deploy.sh

Read the entire output. Do not reboot if the process reports unresolved errors or incomplete package transactions; investigate those messages first.

Step 4 — Reboot and verify

sudo reboot

After reconnecting, confirm the operating system and default boot entry:

cat /etc/redhat-release
sudo grubby --info DEFAULT | grep AlmaLinux

3. Migrate Rocky Linux to AlmaLinux

The official almalinux-deploy project documents support for Rocky Linux 8, 9 and 10 conversion paths. Use the same-major target unless the current official documentation explicitly confirms the path you need. For example, treat Rocky Linux 9 → AlmaLinux 9 as a same-major conversion, not as a major-version upgrade.

1. Confirm the Rocky Linux major release with cat /etc/os-release.
2. Check the official migration guide and script requirements for that release.
3. Back up the system and verify console access, free disk space and repository health.
4. Update the supported source system where appropriate and install required tooling.
5. Download the script from the official project repository and inspect it.
6. Run sudo bash almalinux-deploy.sh from a reliable console session.
7. Review all output, reboot only when the conversion completes successfully, then validate the release, boot entry and services.

cat /etc/os-release
sudo dnf update -y
sudo dnf install -y dnf-plugins-core
curl -O https://raw.githubusercontent.com/AlmaLinux/almalinux-deploy/master/almalinux-deploy.sh
sudo bash almalinux-deploy.sh
sudo reboot

4. Migrate CentOS 7 to AlmaLinux using staged ELevate upgrades

CentOS 7 cannot be converted directly to AlmaLinux 10 using almalinux-deploy. The official AlmaLinux ELevate procedure separates the journey into major-version steps: CentOS 7 → AlmaLinux 8 → AlmaLinux 9 → AlmaLinux 10. Each stage has its own prerequisites, package compatibility checks, reboot and validation.

Stage A — CentOS 7 to AlmaLinux 8

• Read the official ELevate CentOS 7 migration guide in full.
• Back up the server and confirm a working console/rollback route.
• Use the documented CentOS Vault or AlmaLinux-provided repository configuration where required.
• Install the ELevate release package and the correct Leapp upgrade data according to the official guide.
• Run the pre-upgrade assessment, inspect its report and answer file, resolve blockers, perform the upgrade and reboot.

Stage B — AlmaLinux 8 to AlmaLinux 9

• Confirm Stage A completed and the machine boots cleanly into AlmaLinux 8.
• Remove or resolve legacy packages and configuration exclusions as described by the official guide.
• Run the ELevate pre-upgrade assessment for the next major version.
• Resolve inhibitors and answer required questions before initiating the upgrade.
• Upgrade, reboot, then validate system and application health before continuing.

Stage C — AlmaLinux 9 to AlmaLinux 10

Follow the AlmaLinux 9 → 10 procedure in the next section. Do not start Stage C until AlmaLinux 9 has passed your system and application checks.

Official step-by-step reference: ELevate CentOS 7 to AlmaLinux 10 guide. It includes repository handling, the correct staged path and special cases.

5. Upgrade AlmaLinux 9 to AlmaLinux 10

Use the official ELevate/Leapp upgrade workflow. A pre-upgrade report is a required planning tool: it identifies blockers and required answers, and should be reviewed before you begin the actual upgrade.

Step 1 — Update, back up and confirm support

sudo dnf update -y
sudo reboot

After reboot, confirm the system is healthy, ensure backups are restorable, review the current ELevate guide, and verify that your CPU architecture, applications and third-party repositories are supported. AlmaLinux 10 has specific CPU architecture requirements and exceptions; check the official notes for your hardware or VM CPU configuration.

Step 2 — Install ELevate and AlmaLinux upgrade data

sudo dnf install -y https://repo.almalinux.org/elevate/elevate-release-latest-el$(rpm --eval %rhel).noarch.rpm
sudo dnf install -y leapp-upgrade leapp-data-almalinux

Use the current official guide if the package manager rejects the repository URL or if the required package names have changed.

Step 3 — Run the pre-upgrade assessment

sudo leapp preupgrade

Review the report and answer file:

sudo less /var/log/leapp/leapp-report.txt
sudo less /var/log/leapp/answerfile

Resolve every inhibitor and follow each applicable recommendation. Some reports require an explicit answer in the answer file; do not blindly accept settings without understanding their effect. Re-run the pre-upgrade assessment after changes and check the new report.

Step 4 — Start the upgrade

sudo leapp upgrade

Follow the tool’s instructions, retain console access and allow the process to complete. Reboot when instructed. Do not interrupt the upgrade or power off the VM during package transactions.

Step 5 — Validate the upgraded system

cat /etc/redhat-release
cat /etc/os-release
uname -r
systemctl --failed
sudo grubby --info DEFAULT

Validate application services, network routes, DNS, firewall rules, storage mounts, monitoring, backup jobs and security controls. Confirm your application owners have tested their workloads before closing the change.

6. Post-migration validation checklist

• OS and boot: confirm the expected AlmaLinux release and default kernel entry.
• Package manager: run sudo dnf check and inspect failed transactions or repository errors.
• Services: run systemctl --failed and check key application services.
• Networking: validate IP addressing, DNS resolution, routes, firewall rules and remote access.
• Storage: confirm filesystems, mount points, permissions and application data.
• Security: validate SELinux mode, security agents, certificates and access controls.
• Applications: test service health, logs, integrations, scheduled jobs and performance.
• Recovery: confirm backup jobs run successfully and document the final release/configuration.

For a fresh installation instead of an in-place migration, see our companion guide: How to Install AlmaLinux 10 Step by Step (Proxmox, VMware, VirtualBox and Hyper-V).

7. Troubleshooting common problems

Frequently asked questions

Related VMoreCloud guides

Official sources and further reading

• AlmaLinux Migration Guide — supported conversion paths, prerequisites and conversion steps.
• AlmaLinux/almalinux-deploy on GitHub — script requirements and usage.
• ELevate: CentOS 7 to AlmaLinux 10 — staged major-version upgrade path.
• ELevate Quickstart Guide — major-version upgrade preparation and workflow.