Ubuntu vs Linux: what is the difference

Linux is not an operating system. Ubuntu is. That distinction confuses people because the two terms are used interchangeably in casual conversation, but they refer to different things. Linux is the kernel, the core component that talks to the hardware. Ubuntu is a complete operating system built around that kernel, packaged with all the software you need to actually use a computer. Understanding this relationship helps you make better decisions about which operating system to run on your servers and what the differences between distributions actually mean.

What Linux actually is#

Linux is a kernel. The kernel is the lowest-level software that runs on a computer. It manages hardware resources (CPU, memory, disk, network), handles process scheduling, enforces permissions, manages file systems, and provides the interface between hardware and software. When a program wants to read a file, send network data, or allocate memory, it asks the kernel.

Linus Torvalds wrote the first version of the Linux kernel in 1991. It was inspired by MINIX, a teaching operating system, and influenced by the UNIX operating system philosophy. The kernel itself is open source under the GPL license, which means anyone can read, modify, and distribute it.

But a kernel alone is not something you can use. You cannot type commands into a kernel. You cannot browse the web with a kernel. You cannot run WordPress on a kernel. You need a shell (bash, zsh), a package manager (apt, dnf), system utilities (ls, cp, grep, systemctl), a web server (Nginx, Apache), a database (MySQL, PostgreSQL), and thousands of other pieces of software to build a usable system.

That is where distributions come in.

What a Linux distribution is#

A Linux distribution (distro) takes the Linux kernel and packages it with all the software needed to create a complete, usable operating system. A distribution includes:

• The Linux kernel (a specific version, sometimes with custom patches)
• A package manager and software repositories
• System initialization software (systemd on most modern distros)
• A shell (usually bash)
• Core utilities (GNU coreutils: ls, cp, mv, grep, awk, sed)
• A package of pre-installed software appropriate for the distro’s target audience
• Default configuration files tuned for the distro’s use case
• An installer
• Documentation and community support

Different distributions make different decisions about which versions of software to include, how often to update, how long to support each release, and what the default configuration looks like. These decisions define the character of each distribution and determine which one is the best fit for a given use case.

Ubuntu: the most popular server distribution#

Ubuntu is a Linux distribution created by Canonical Ltd, first released in 2004. It is based on Debian and shares Debian’s package management system (apt/dpkg) and much of its package ecosystem.

Ubuntu releases a new version every six months (April and October). Every two years, the April release is designated as an LTS (Long Term Support) release, which receives security updates for five years (ten years with Ubuntu Pro). Current LTS releases include 24.04 (Noble Numbat), 22.04 (Jammy Jellyfish), and 20.04 (Focal Fossa).

Ubuntu became the most popular Linux distribution for servers because:

• Frequent, predictable release schedule. You know when the next version is coming and how long it will be supported.
• Large package repositories. More pre-packaged software than most other distributions, so you rarely need to compile from source.
• Strong community. The largest Linux community means more documentation, more tutorials, more Stack Overflow answers, and more people who can help when something goes wrong.
• PPAs (Personal Package Archives). Third-party developers can easily publish packages for Ubuntu, which means newer versions of software are often available through PPAs before they reach the official repositories.
• Canonical’s backing. Commercial support, certifications, and enterprise features are available for organizations that need them.

For checking which Ubuntu version you are running, see How to check your Ubuntu version. For installing software on Ubuntu, see How to install PHP on Ubuntu and How to install MySQL on Ubuntu.

Other major Linux distributions#

Debian

Debian is the distribution Ubuntu is based on. It prioritizes stability over having the latest software. Debian releases are less frequent than Ubuntu and packages go through a longer testing process before being included in the stable release.

Best for: Servers where stability is the absolute priority and you do not need the latest package versions. Debian’s stable release is rock-solid but the included software versions can be years behind current releases.

Package manager: apt/dpkg (same as Ubuntu)

Rocky Linux / AlmaLinux

Rocky Linux and AlmaLinux are community-maintained distributions that are binary-compatible with Red Hat Enterprise Linux (RHEL). They were created after CentOS shifted from being a RHEL clone to CentOS Stream (a rolling-release development branch of RHEL).

Rocky Linux was founded by Gregory Kurtzer, the original co-founder of CentOS, specifically to fill the gap CentOS left. AlmaLinux was created by CloudLinux for the same purpose.

Best for: Production servers that need RHEL compatibility without the RHEL subscription cost. Enterprise workloads, hosting infrastructure, and any environment where RHEL-compatible packages and long support cycles matter.

Package manager: dnf/rpm

Hostney’s production servers run Rocky Linux 9 and Rocky Linux 10. The choice is driven by RHEL compatibility, long support cycles (10 years), and the stability and predictability that comes with the RHEL ecosystem.

CentOS Stream

CentOS Stream is the development branch for RHEL. It receives updates before RHEL, making it a rolling preview of the next RHEL minor release. It is no longer a downstream rebuild of RHEL like the original CentOS was.

Best for: Development and testing environments where you want to preview upcoming RHEL changes. Not recommended for production servers that need the stability of a fixed release.

Package manager: dnf/rpm

Fedora

Fedora is the upstream distribution for RHEL. It gets the latest software first, which eventually makes its way into RHEL and then Rocky/Alma. Fedora releases a new version roughly every six months with about 13 months of support per release.

Best for: Developers and enthusiasts who want the latest software. Workstations and development environments. Not typically used for production servers because the support window is too short.

Package manager: dnf/rpm

Arch Linux

Arch is a rolling-release distribution that always has the latest software. There are no version numbers or release cycles. You install once and update continuously. Arch requires manual installation and configuration, the installer does not configure anything automatically.

Best for: Experienced Linux users who want complete control and the latest packages. Development environments and personal workstations. Not suitable for production servers because rolling releases mean any update can introduce breaking changes.

Package manager: pacman

SUSE Linux Enterprise / openSUSE

SUSE Linux Enterprise Server (SLES) is an enterprise distribution from SUSE, a German company. openSUSE is its community counterpart. SUSE is popular in Europe and in enterprise environments, particularly for SAP workloads.

Best for: Enterprise environments, particularly those running SAP. Less common in the web hosting world than RHEL/Ubuntu.

Package manager: zypper/rpm

How distributions affect your server#

The distribution you run determines the default software versions available, the package management commands you use, the file system layout for configuration files, and the support lifecycle.

Package management

The most visible difference between distributions is how you install software:

# Ubuntu/Debian
sudo apt update
sudo apt install nginx

# Rocky Linux/CentOS/RHEL/Fedora
sudo dnf install nginx

# Arch
sudo pacman -S nginx

The underlying software is the same Nginx regardless of distribution. The package manager just handles how it is downloaded, installed, and updated.

Default software versions

Different distributions ship different versions of the same software. This matters for compatibility:

Rocky Linux tends to ship older but more stable versions. Ubuntu tends to ship newer versions. Both can run newer software through third-party repositories or application streams, but the defaults differ.

Configuration file locations

Configuration files live in slightly different places depending on the distribution:

# Nginx config
# Ubuntu/Debian: /etc/nginx/sites-available/ and sites-enabled/
# Rocky/RHEL: /etc/nginx/conf.d/

# PHP-FPM pool config
# Ubuntu: /etc/php/8.3/fpm/pool.d/
# Rocky: /etc/php-fpm.d/

# MySQL config
# Ubuntu: /etc/mysql/mysql.conf.d/
# Rocky: /etc/my.cnf.d/

This is why server administration guides often specify the distribution. A guide written for Ubuntu may have wrong file paths for Rocky Linux, and vice versa.

Support lifecycle

For servers, support length matters. Running a distribution past its end-of-life date means no security patches, which is a significant risk for any internet-facing system. The same principle applies to the software running on the server. Running end-of-life PHP on a supported distribution still leaves you exposed.

Which distribution should you use#

For web hosting and WordPress servers: Ubuntu LTS or Rocky Linux. Both are well-supported, widely documented, and have long support lifecycles. Ubuntu is more common in tutorials and has larger community support. Rocky Linux is more common in enterprise and hosting infrastructure. For understanding the differences between hosting types (shared, VPS, managed), see VPS vs shared hosting and what is managed WordPress hosting.

For development environments: Ubuntu or Fedora. Both have recent software versions and large package repositories. Fedora has the newest packages but shorter support.

For learning Linux: Ubuntu. The largest community and the most documentation make it the easiest starting point. Almost every Linux tutorial online uses Ubuntu as the reference distribution.

For enterprise workloads: Rocky Linux, AlmaLinux, or RHEL. The 10-year support lifecycle and RHEL compatibility are important for environments with long planning horizons and compliance requirements.

The distribution choice matters less than people think for most use cases. The Linux kernel is the same across all of them. The core utilities are the same. The web server, database, and PHP interpreter are the same software regardless of which distribution packages them. The differences are in packaging, default configurations, support timelines, and community size. Pick one that matches your support needs and that your team is comfortable administering, and stick with it.

Quick reference#