As CentOS 7 approaches its end of life on June 30, 2024, system administrators managing servers running this operating system need to plan for migration to a new distribution.
One viable option is Ubuntu 24.04 LTS, a stable and well-supported Linux distribution with a large community.
This guide will walk you through the knowledge and steps needed to migrate your CentOS 7 servers to Ubuntu 24.04 with minimal downtime and data loss.
CentOS Alternatives
Before proceeding with the migration, it’s important to evaluate alternative options that suit your organization’s needs.
Some popular alternatives to CentOS include:
- RHEL (Red Hat Enterprise Linux): Offers excellent support for migration, SELinux platform, but requires paid support.
- CentOS Stream: Built by the same team as CentOS, making migration simpler, but less stable due to its rolling-release nature.
- AlmaLinux: Targeted at CentOS users, offering high compatibility.
- Debian: Stable, open-source, and a favorite among system administrators.
- Ubuntu: Similar to Debian, with a large community and extensive documentation.
- Rocky Linux: Preferred choice for those who like Red Hat’s distribution style.
Why Migrate to Ubuntu?
Here are some key reasons to migrate from CentOS 7 to Ubuntu 24.04 LTS:
- Long-Term Support (LTS): Ubuntu offers LTS (Long Term Support) releases, guaranteeing security updates and package maintenance for 5 years. This is important since CentOS 7 will reach end-of-life on June 30, 2024.
- Large Community & Support – Ubuntu boasts a vast and active community, providing extensive documentation and troubleshooting resources. Additionally, numerous commercial support options are available.
- Package Availability: A vast repository of software packages caters to diverse needs. You’ll likely find equivalents for most of the software currently running on your CentOS servers.
- Package Management: Ubuntu uses the apt package manager and DEB packages, which are similar to the YUM package manager and RPM packages used in CentOS.
Planning Your Migration
Before diving into the migration process, some planning is crucial.
- Inventory and Assessment: Create a detailed inventory of your servers, including hardware specifications, software installed, and configuration details, which helps in identifying potential compatibility issues during migration.
- Backup Strategy: Data loss is a critical concern, that is why implement a robust backup strategy to ensure you can restore your data in case of migration problems. Consider full system backups or backups of specific directories depending on your needs.
- Downtime Considerations: Determine acceptable downtime windows for your servers. Schedule the migration during low-traffic periods to minimize service disruption.
Backup CentOS 7 System
Use tools like rsync, tar, or scp to back up your important files and configurations from your CentOS server to a temporary location on your machine or remote machine.
The following rsync command will securely copy all your files and folders (including hidden ones) from the source directory to the destination in the same machine:
sudo rsync -avz /path/to/source/directory /path/to/destination/directory
The following tar command creates a compressed backup archive of a directory on your system.
sudo tar -cvzf backup.tgz /path/to/source/directory
The following scp command securely copies a directory and its contents from your CentOS system to a remote system.
scp -r /path/to/source/directory username@remote_host:/path/to/destination/directory
Install New Ubuntu System
Download the Ubuntu LTS ISO image and create a bootable USB drive. Boot your server from the USB drive and choose “Install Ubuntu“.
During installation, choose the appropriate options for your hardware and desired desktop environment (e.g., GNOME) or opt for a minimal installation if you prefer a command-line-based server.
Once your Ubuntu production environment is ready, configure firewalls, update network details, and configure any important configuration files.
Research Ubuntu repositories to find replacements for the software currently running on your CentOS server. Many popular applications have direct equivalents in Ubuntu.
Use the apt package manager on Ubuntu to install the identified software packages.
Transfer the Backup to Ubuntu
Transferring data from a remote CentOS 7 system to a local Ubuntu system involves several steps to ensure that your data is transferred accurately and securely.
First, make sure that rsync is installed on the Ubuntu system.
sudo apt update sudo apt install rsync
Use the rsync command to transfer data from the remote CentOS system to your local Ubuntu system.
rsync -avz -e ssh username@remote-centos-ip:/path/to/remote/data /path/to/local/destination
Testing and Verification
Thoroughly test all functionalities of your migrated server to ensure everything is working as expected. Also, verify that security measures like firewalls and user permissions are properly configured on your Ubuntu system.
Once testing is complete, reboot your server to apply any final configuration changes.
I suggest you document all the changes made during the migration process, including system changes, configuration changes, and application changes. This will help you track the changes and ease future troubleshooting efforts.
Conclusion
Migrating from CentOS 7 to Ubuntu 24.04 can be a challenging task, but with proper planning and execution, it can be achieved with minimal downtime and data loss.
By following the steps outlined in this guide, system administrators can ensure a smooth transition to a stable and well-supported Linux distribution.
