Differences between Linux Distributions: Ubuntu vs Debian vs CentOS vs Rocky Linux

Understanding the differences between major Linux distributions is crucial for system administrators, developers, and DevOps engineers. Whether you're deploying production servers, building containerized applications, or managing enterprise infrastructure, choosing the right Linux distribution can significantly impact your project's success, maintenance costs, and long-term sustainability.

This comprehensive guide explores the key differences between Ubuntu, Debian, CentOS, and Rocky Linux, examining their package management systems, release cycles, enterprise support, security features, and ideal use cases. By the end of this guide, you'll have a clear understanding of what sets these distributions apart and which one aligns best with your specific requirements.

Table of Contents

• Introduction
• Understanding Linux Distribution Families
• Ubuntu: The Developer-Friendly Distribution
• Debian: The Universal Operating System
• CentOS Legacy and Rocky Linux: The Enterprise Alternative
• Package Management Comparison
• Release Cycles and Support Periods
• Security and Updates
• Performance Considerations
• Enterprise Support and Commercial Options
• Community and Documentation
• Best Practices for Choosing a Distribution
• Conclusion

Introduction

Linux distributions, often called "distros," are complete operating systems built around the Linux kernel. While they all share the same core kernel, distributions differ significantly in their philosophy, package management, release schedules, default configurations, and target audiences.

The four distributions covered in this guide represent the most popular choices for server deployments:

• Ubuntu: Based on Debian, known for regular releases and extensive community support
• Debian: The "Universal Operating System," prized for stability and free software commitment
• CentOS: Historically a free rebuild of Red Hat Enterprise Linux (now sunset)
• Rocky Linux: A community-driven RHEL-compatible distribution replacing CentOS

Understanding these differences is not just academic knowledge. The wrong distribution choice can lead to compatibility issues, increased maintenance burden, premature end-of-life situations, and unexpected costs. The right choice ensures long-term stability, access to necessary packages, and alignment with your team's expertise.

Understanding Linux Distribution Families

Linux distributions are typically grouped into families based on their ancestry and package management systems. The two major families relevant to our discussion are:

Debian Family

The Debian family includes Debian itself and its derivatives, most notably Ubuntu. These distributions share several characteristics:

• Use DEB package format (.deb files)
• Employ APT (Advanced Package Tool) for package management
• Follow similar directory structures and conventions
• Generally use systemd as the init system (modern versions)

# Checking your Debian family distribution
cat /etc/os-release | grep -E "^(NAME|VERSION)"

Red Hat Family

The Red Hat family includes Red Hat Enterprise Linux (RHEL), CentOS, Rocky Linux, AlmaLinux, and Fedora. Key characteristics include:

• Use RPM package format (.rpm files)
• Employ YUM or DNF for package management
• Share similar configuration file locations
• Use SELinux as the primary mandatory access control system

# Checking your Red Hat family distribution
cat /etc/redhat-release

Understanding these family relationships helps predict behavior, troubleshoot issues, and transfer knowledge between similar distributions.

Ubuntu: The Developer-Friendly Distribution

Ubuntu, created by Canonical Ltd. in 2004, has become one of the most popular Linux distributions for both desktop and server environments. Built on Debian's foundation, Ubuntu distinguishes itself through predictable release cycles, extensive documentation, and strong commercial backing.

Key Characteristics

Release Cycle: Ubuntu follows a strict six-month release cycle, with new versions appearing in April (XX.04) and October (XX.10) each year. Long Term Support (LTS) releases appear every two years in April and receive five years of free security updates.

# Check Ubuntu version
lsb_release -a

# Example output:
# Distributor ID: Ubuntu
# Description:    Ubuntu 22.04.3 LTS
# Release:        22.04
# Codename:       jammy

LTS vs Regular Releases: LTS releases like 20.04 (Focal Fossa) and 22.04 (Jammy Jellyfish) are recommended for production servers. Regular releases receive only nine months of support and are better suited for testing new features.

Package Management

Ubuntu uses APT and supports both DEB packages and Snap packages (Canonical's universal package format):

# Update package index
sudo apt update

# Upgrade installed packages
sudo apt upgrade

# Install a package
sudo apt install nginx

# Search for packages
apt search apache2

# Install snap package
sudo snap install docker

Advantages

• Extensive Documentation: Ubuntu's documentation is comprehensive and beginner-friendly
• Large Package Repository: Access to thousands of pre-compiled packages
• Regular Updates: Predictable release schedule helps with planning
• Commercial Support: Canonical offers Ubuntu Advantage for enterprise support
• Cloud Integration: Excellent support on AWS, Azure, Google Cloud, and other platforms
• Container-Friendly: Popular base image for Docker containers

Disadvantages

• Snap Package Controversy: Some users prefer traditional package managers
• More Bleeding Edge: Non-LTS releases can introduce instability
• Commercial Influence: Some decisions prioritized for commercial reasons
• Resource Usage: Generally uses more resources than minimal Debian installations

Ideal Use Cases

• Development environments requiring recent software versions
• Startups needing rapid deployment with extensive online resources
• Cloud-native applications and microservices
• Organizations requiring commercial support options
• Teams familiar with Debian-based systems

Debian: The Universal Operating System

Debian, established in 1993, is one of the oldest and most respected Linux distributions. Known for its commitment to free software, stability, and rigorous testing, Debian serves as the foundation for hundreds of derivative distributions, including Ubuntu.

Key Characteristics

Release Cycle: Debian follows a "release when ready" approach rather than a fixed schedule. Releases typically occur every two to three years and receive long-term support for five years.

# Check Debian version
cat /etc/debian_version

# More detailed information
cat /etc/os-release

Branches: Debian maintains three primary branches:

• Stable: The current production release, thoroughly tested
• Testing: The next future stable release, receiving newer packages
• Unstable (Sid): Rolling release with the newest packages, less stable

Package Management

Debian uses APT exclusively, with a massive repository of over 59,000 packages:

# Update package database
sudo apt update

# Upgrade all packages
sudo apt full-upgrade

# Install a package
sudo apt install postgresql

# Remove package and configuration
sudo apt purge package-name

# List installed packages
dpkg -l | grep package-name

Advantages

• Legendary Stability: Rigorous testing ensures rock-solid reliability
• Free Software Commitment: Strong emphasis on open-source principles
• Wide Architecture Support: Runs on more hardware architectures than competitors
• No Corporate Influence: Community-driven development
• Minimal Base System: Extremely lightweight default installation
• Package Abundance: Largest software repository in the Linux world

Disadvantages

• Outdated Packages: Stable branch prioritizes stability over newest versions
• Slower Release Cycle: New features take longer to reach stable branch
• Steeper Learning Curve: Less hand-holding than Ubuntu
• No Official Commercial Support: Community-only support unless you hire consultants
• Complex Release Upgrade Process: Major version upgrades require careful planning

Ideal Use Cases

• Production servers requiring maximum stability
• Organizations prioritizing free software principles
• Long-running servers with minimal maintenance windows
• Embedded systems and specialized hardware
• Users who prefer minimal systems they can build upon
• Environments where software age matters less than reliability

CentOS Legacy and Rocky Linux: The Enterprise Alternative

The Red Hat ecosystem has undergone significant changes in recent years, creating new options for users seeking RHEL-compatible distributions.

CentOS History and Discontinuation

CentOS (Community Enterprise Operating System) was created in 2004 as a free, community rebuild of Red Hat Enterprise Linux. It provided binary compatibility with RHEL without the subscription costs, making it extremely popular for server deployments.

The CentOS Shift: In December 2020, Red Hat announced that CentOS Linux would be discontinued, with CentOS 8 reaching end-of-life on December 31, 2021. The project shifted focus to CentOS Stream, a rolling-release distribution that sits upstream of RHEL rather than downstream.

Rocky Linux: The CentOS Successor

Rocky Linux emerged as a direct response to CentOS's discontinuation. Founded by Gregory Kurtzer (original CentOS founder), Rocky Linux aims to provide bug-for-bug compatibility with RHEL while remaining community-governed.

# Check Rocky Linux version
cat /etc/rocky-release

# Detailed system information
hostnamectl

Key Characteristics

Release Cycle: Rocky Linux follows RHEL's release cycle, with major versions receiving approximately 10 years of support. Each minor version appears shortly after the corresponding RHEL release.

Binary Compatibility: Rocky Linux provides 1:1 binary compatibility with RHEL, meaning software compiled for RHEL will run on Rocky Linux without modification.

Package Management

Rocky Linux uses DNF (Dandified YUM), the modern successor to YUM:

# Update package cache
sudo dnf check-update

# Upgrade all packages
sudo dnf upgrade

# Install a package
sudo dnf install httpd

# Search for packages
dnf search nginx

# List repositories
dnf repolist

# Install from EPEL (Extra Packages for Enterprise Linux)
sudo dnf install epel-release
sudo dnf install htop

Advantages

• Enterprise Stability: Inherits RHEL's conservative, enterprise-focused approach
• Long Support Cycles: Up to 10 years of support per major version
• Binary RHEL Compatibility: Drop-in replacement for RHEL in most scenarios
• SELinux Integration: Enhanced security out of the box
• Strong Enterprise Focus: Features and testing geared toward production environments
• Predictable Update Schedule: Follows RHEL's well-planned release cycle
• Community Governed: Rocky Enterprise Software Foundation ensures community control

Disadvantages

• Older Packages: Conservative approach means older software versions
• Smaller Repository: Fewer packages than Debian/Ubuntu repositories
• Dependency on RHEL: Release schedule tied to Red Hat's decisions
• Younger Ecosystem: Rocky Linux is relatively new (2021)
• Learning Resources: Less abundant than Ubuntu documentation
• Limited EPEL Compatibility: Extra repositories sometimes lag behind

AlmaLinux: The Alternative to Rocky Linux

AlmaLinux is another RHEL-compatible distribution created by CloudLinux in response to CentOS's discontinuation. It offers similar benefits to Rocky Linux with backing from CloudLinux's commercial resources.

# Check AlmaLinux version
cat /etc/almalinux-release

Ideal Use Cases

• Enterprise production servers requiring long-term stability
• Organizations migrating from CentOS or requiring RHEL compatibility
• Environments where software certification matters (databases, enterprise apps)
• Systems requiring enhanced SELinux security
• Teams with Red Hat/CentOS experience
• Regulated industries with strict compliance requirements

Package Management Comparison

Package management is one of the most significant day-to-day differences between distributions.

APT vs DNF/YUM

Package Availability

# Compare available packages for Python development
# Ubuntu/Debian
apt search python3 | wc -l

# Rocky Linux/CentOS
dnf search python3 | wc -l

Debian-based distributions typically have more packages available in their default repositories. However, Rocky Linux users can add EPEL (Extra Packages for Enterprise Linux) to access thousands of additional packages:

# Enable EPEL on Rocky Linux
sudo dnf install epel-release
sudo dnf config-manager --set-enabled powertools

Repository Management

Ubuntu/Debian uses /etc/apt/sources.list and /etc/apt/sources.list.d/:

# Add a repository
sudo add-apt-repository ppa:repository/name
sudo apt update

# Manually edit sources
sudo nano /etc/apt/sources.list

Rocky Linux uses repository files in /etc/yum.repos.d/:

# Add a repository
sudo dnf config-manager --add-repo https://example.com/repo.repo

# Enable/disable repository
sudo dnf config-manager --set-enabled repository-name
sudo dnf config-manager --set-disabled repository-name

Release Cycles and Support Periods

Understanding release cycles and support timelines is critical for production planning.

Ubuntu Support Timeline

# Check support status
ubuntu-support-status

Debian Support Timeline

Debian's support timeline is less predictable but generally offers:

• Active Support: Approximately 3 years from release
• LTS (Long Term Support): Additional 2 years (5 years total)
• ELTS (Extended LTS): Commercial option for extended support

Rocky Linux Support Timeline

Rocky Linux follows RHEL's lifecycle:

• Major Version: 10 years of support
• Full Support: First 5 years (updates and new features)
• Maintenance Support: Next 5 years (critical security fixes only)

# Check system lifecycle on Rocky Linux
sudo dnf install redhat-lsb-core
lsb_release -a

Security and Updates

Security is paramount in production environments, and distributions handle it differently.

Security Update Philosophy

Ubuntu: Releases security updates rapidly, sometimes within hours of vulnerability disclosure. Canonical maintains a security team that triages CVEs and backports patches.

# Install security updates only
sudo apt install unattended-upgrades
sudo dpkg-reconfigure --priority=low unattended-upgrades

Debian: Extremely rigorous security update process. The Debian Security Team coordinates with upstream developers and tests patches thoroughly.

# Configure automatic security updates
sudo apt install unattended-upgrades apt-listchanges

Rocky Linux: Inherits RHEL's conservative security approach. Updates are thoroughly tested but may appear slightly delayed compared to Ubuntu.

# Enable automatic security updates
sudo dnf install dnf-automatic
sudo systemctl enable --now dnf-automatic.timer

SELinux vs AppArmor

Rocky Linux uses SELinux (Security-Enhanced Linux) by default:

# Check SELinux status
sestatus

# Set SELinux to enforcing mode
sudo setenforce 1

# View SELinux denials
sudo ausearch -m avc -ts recent

Ubuntu uses AppArmor for mandatory access control:

# Check AppArmor status
sudo aa-status

# Reload AppArmor profiles
sudo systemctl reload apparmor

Debian includes both but doesn't enable either by default, allowing administrators to choose.

Performance Considerations

Performance differences between distributions are usually minimal, as they share the same Linux kernel and can run identical software stacks.

Default Configuration Differences

Ubuntu: More services enabled by default, slightly higher baseline resource usage.

# List running services
systemctl list-units --type=service --state=running

Debian: Minimal default installation, giving administrators more control over what runs.

# Count running processes on Debian minimal install
ps aux | wc -l

Rocky Linux: Enterprise-oriented defaults with SELinux enabled, slightly more overhead but enhanced security.

Kernel Differences

All distributions use the Linux kernel but may ship different versions and patches:

# Check kernel version
uname -r

# View kernel configuration
cat /boot/config-$(uname -r) | grep CONFIG_PREEMPT

Ubuntu typically ships newer kernels, while Rocky Linux ships more conservative, thoroughly tested versions. For most applications, kernel version differences have negligible impact.

Enterprise Support and Commercial Options

Ubuntu Advantage

Canonical offers Ubuntu Advantage (UA) subscriptions providing:

• Extended Security Maintenance (ESM) beyond the 5-year LTS period
• Livepatch service for kernel updates without rebooting
• FIPS compliance modules
• 24/7 phone and ticket support
• Legal assurance for open source components

# Attach Ubuntu Advantage subscription
sudo ua attach YOUR_TOKEN

# Enable ESM
sudo ua enable esm-infra

Debian Commercial Support

Debian itself doesn't offer commercial support, but numerous companies provide:

• Freexian ELTS (Extended LTS)
• Third-party consulting and support contracts
• Custom enterprise solutions

Rocky Linux Support Options

Rocky Linux is community-supported, but commercial options are emerging:

• TuxCare Extended Lifecycle Support
• CloudLinux support for AlmaLinux (similar distribution)
• Third-party consulting services
• Migrate to RHEL for official Red Hat support

Community and Documentation

Ubuntu Community

• Forums: Ubuntu Forums and Ask Ubuntu (Stack Exchange)
• Documentation: Extensive official documentation and community wiki
• IRC/Matrix: Active real-time support channels
• Launchpad: Bug tracking and development platform

# Get help for any command
man command-name
# or
command-name --help

Debian Community

• Mailing Lists: Primary communication channel
• Documentation: Thorough official documentation, Debian Wiki
• IRC: Active IRC channels on OFTC network
• Bug Tracking: Debian Bug Tracking System (BTS)

Rocky Linux Community

• Forums: Community forums and Mattermost chat
• Documentation: Growing documentation based on RHEL knowledge
• Bug Tracking: Rocky Linux Bug Tracker
• Special Interest Groups: Focused working groups for specific topics

Best Practices for Choosing a Distribution

Decision Framework

When selecting a distribution, consider these factors:

1. Support Timeline: How long do you need to maintain this system?
2. Package Requirements: What software versions do you need?
3. Team Expertise: What is your team familiar with?
4. Certification Requirements: Does your software require specific distributions?
5. Compliance Needs: Are there regulatory requirements?
6. Budget: Can you afford commercial support if needed?

Recommendation Matrix

Choose Ubuntu if you:

• Need recent software versions
• Want extensive online resources and community support
• Are building cloud-native applications
• Require commercial support options with flexible pricing
• Value predictable release schedules

Choose Debian if you:

• Prioritize stability over new features
• Prefer complete control over your system
• Need maximum hardware architecture support
• Value free software principles
• Have experienced Linux administrators

Choose Rocky Linux if you:

• Migrating from CentOS
• Need RHEL binary compatibility
• Require 10-year support lifecycles
• Work in regulated industries
• Have existing RHEL-based infrastructure
• Need robust SELinux support

Testing Before Commitment

Always test your specific workload on your chosen distribution:

# Create a test VM with VirtualBox
# or use Docker for quick testing

# Test Ubuntu
docker run -it ubuntu:22.04 /bin/bash

# Test Debian
docker run -it debian:12 /bin/bash

# Test Rocky Linux
docker run -it rockylinux:9 /bin/bash

Migration Considerations

If you need to migrate between distributions:

From Ubuntu to Debian (or vice versa)

Package names are often identical or similar:

# Export installed packages on Ubuntu
dpkg --get-selections > installed-packages.txt

# Install on Debian (after reviewing)
dpkg --set-selections < installed-packages.txt
apt-get dselect-upgrade

From CentOS to Rocky Linux

Rocky Linux provides migration scripts:

# Download migration script
curl https://raw.githubusercontent.com/rocky-linux/rocky-tools/main/migrate2rocky/migrate2rocky.sh -o migrate2rocky.sh

# Run migration (backup first!)
sudo bash migrate2rocky.sh -r

From Debian/Ubuntu to Rocky Linux

This requires a fresh installation as package formats differ:

1. Document all installed packages and configurations
2. Export data and databases
3. Perform fresh installation
4. Reinstall applications using DNF
5. Restore data and configurations

Conclusion

Choosing between Ubuntu, Debian, CentOS/Rocky Linux depends on your specific requirements, team expertise, and long-term goals. Ubuntu excels in cloud environments and developer workstations with its modern package versions and extensive documentation. Debian shines in production servers requiring legendary stability and minimal resource usage. Rocky Linux provides enterprise-grade reliability with RHEL compatibility for organizations needing long support lifecycles and security-focused configurations.

There is no universally "best" distribution. Ubuntu's six-month release cycle suits rapidly evolving applications, while Rocky Linux's 10-year support timeline matches enterprise planning horizons. Debian's "when ready" approach serves those who value stability above all else.

The most important consideration is choosing a distribution your team can effectively manage, that meets your application's requirements, and that aligns with your organization's support and lifecycle needs. Test your specific workloads, consider your long-term maintenance strategy, and choose the distribution that best fits your operational reality.

Remember that all of these distributions are excellent, production-ready systems powering millions of servers worldwide. Your choice should be based on practical considerations rather than ideological preferences. The time invested in choosing the right distribution will pay dividends in reduced maintenance burden, better security posture, and improved operational efficiency.

Next Steps

After choosing your distribution:

1. Set up a test environment matching your production requirements
2. Document your decision rationale for future reference
3. Train your team on distribution-specific tools and conventions
4. Establish update and maintenance procedures
5. Plan for end-of-life scenarios and future migrations
6. Monitor security advisories for your chosen distribution

By understanding the differences between these major Linux distributions, you're better equipped to make informed infrastructure decisions that will serve your organization for years to come.