Ubuntu, Debian, AlmaLinux or Rocky: which Linux?

If you don't know what to pick, start with Ubuntu Server LTS. Many software guides assume Ubuntu, and every LTS release gets five years of standard security maintenance. Debian suits people who want a plain, long-lived base. AlmaLinux and Rocky Linux fit when you need an environment compatible with RHEL, for example for software built for it or to match enterprise habits.

The four distributions side by side

The lengths come from the official pages of Ubuntu, Debian, AlmaLinux and Rocky Linux. Check the current end date of the release you pick there before you install.

Picking a release and checking what you run

An Ubuntu version number is its release year and month. LTS releases come out every two years in April, for example 24.04. Interim releases are supported for a much shorter time, so choose an LTS for a server. Debian versions carry a code name next to the number. The RHEL family uses major versions such as 8, 9 and 10. Whichever distribution you choose, install a new server with the newest LTS or stable release. An older release leaves you a shorter support window. If you will use a panel, first check that the panel supports that release.

cat /etc/os-release shows which distribution and version you are running. To see whether a reboot is needed after updates, check for the file /var/run/reboot-required on Ubuntu. On the RHEL family, sudo dnf needs-restarting -r tells you. Kernel updates usually don't take effect without a reboot.

Where do they really differ?

• Commands. On Ubuntu and Debian you install packages with apt, and on AlmaLinux and Rocky with dnf: sudo apt install nginx or sudo dnf install nginx. Package names sometimes differ too. Apache is apache2 on one side and httpd on the other.
• Security framework. On Ubuntu, AppArmor is installed and enabled by default. In the RHEL family, SELinux comes in enforcing mode by default (according to Red Hat's documentation). SELinux can stop a web server from writing to an unusual folder or binding to a non-standard port. The fix is usually to set the right label, not to turn SELinux off.
• Automatic security updates. On Ubuntu the unattended-upgrades package is there from the start. It installs security updates once a day and doesn't reboot the server on its own (according to the Ubuntu documentation). Debian uses the same package: if it isn't installed, install it with sudo apt install unattended-upgrades and enable it. On AlmaLinux and Rocky you install dnf-automatic with sudo dnf install dnf-automatic and run sudo systemctl enable --now dnf-automatic-install.timer. The default setting installs all updates, not only security ones. For security updates only, set upgrade_type to security in /etc/dnf/automatic.conf.
• Package versions. On these distributions, package versions usually stay fixed, and security patches arrive by being backported to the older version. If you need something newer, use the application's own repository or Docker.

What does your software want?

Often the software you will run makes the choice for you. According to the panels' official documentation, CloudPanel requires Ubuntu or Debian, and HestiaCP requires Debian or Ubuntu LTS. cPanel supports AlmaLinux, Rocky Linux, CloudLinux and Ubuntu. DirectAdmin supports the RHEL family, Debian and Ubuntu. If you will use a panel, look at the list it supports first, and choose the distribution after that.

After CentOS: AlmaLinux or Rocky?

Support for CentOS Linux 8 ended on December 31, 2021, and support for CentOS Linux 7 ended on June 30, 2024, according to the CentOS project's announcements. CentOS Stream is a continuously delivered distribution that runs one step ahead of RHEL. AlmaLinux and Rocky Linux are free community distributions that are compatible with RHEL. Most of the commands in old CentOS guides work on both of them.

AlmaLinux is run by the nonprofit AlmaLinux OS Foundation, and the Rocky Linux trademark belongs to the Rocky Enterprise Software Foundation. In everyday use they behave alike. Your panel's support, your knowledge and your habits mostly decide.

A short recommendation

• Your first server, WordPress, Docker, general use: Ubuntu LTS.
• A plain base that changes little: Debian.
• A panel or software that needs RHEL compatibility: AlmaLinux or Rocky. Both are free community distributions, and the choice is mostly personal.
• If you don't want to upgrade for a long time: look at the end-of-support date of the release you pick and put it in your calendar.
• If you have an old CentOS server: check that your application supports AlmaLinux or Rocky Linux before you move. Then build the new server and move the data there.

On Seturack

If you choose a ready-made app, you don't pick the distribution separately; the right one is installed for it. Most apps run on Ubuntu 24.04 LTS, and cPanel runs on AlmaLinux 9. If you choose an operating system only, you see the distributions and versions on the order screen. If you want to change the distribution later, the panel has a reinstall tool, but it deletes all data on the server. Copy the files you need to your computer before you start.