What Is CentOS? An Overview of the CentOS Operating System

With its high stability, strong security, and flexible customization capabilities, CentOS has long been one of the top choices for server environments, enterprise infrastructures, and open-source projects.

In this article, Viettel IDC provides a comprehensive overview of CentOS, including its history, key features, advantages, limitations, and use cases.

What Is CentOS?

CentOS (Community Enterprise Operating System) is an open-source Linux distribution built from the source code of Red Hat Enterprise Linux (RHEL) and designed primarily for community use.

Thanks to its reliability and enterprise-grade stability, CentOS is widely used in production environments where uptime and service continuity are critical. One of its standout characteristics is its high level of customization, allowing system administrators to configure the operating system for various use cases—from small businesses to large-scale enterprise infrastructures.

Another key advantage of CentOS is that it is completely free to use, unlike RHEL which requires a paid subscription. Developers and organizations can deploy, scale, and customize their systems without worrying about licensing costs.

The combination of RHEL’s proven stability and CentOS’s free accessibility has made it a popular choice within the professional Linux community for many years.

The Development History of CentOS

CentOS was first introduced in 2004, when the open-source community decided to create a Linux distribution based on the source code of Red Hat Enterprise Linux.

The primary goal of the project was to provide a free, enterprise-grade operating system that the community could use, maintain, and improve collaboratively. Over the years, CentOS proved itself to be one of the most reliable Linux platforms for scalable and maintainable server environments.

However, in late 2020, Red Hat announced a major shift in the project’s direction. Development of CentOS Linux would transition to CentOS Stream, a rolling-release distribution positioned between Fedora and RHEL that previews upcoming RHEL features.

This change sparked significant debate within the CentOS community, particularly among users who relied on CentOS as a stable downstream rebuild of RHEL.

With the introduction of CentOS Stream, users had to either adapt to the new development model or explore alternative solutions.

Despite these changes, the core values associated with CentOS—open source, stability, and accessibility—remain influential. Many developers and organizations continue to rely on traditional CentOS versions or migrate to RHEL-compatible distributions such as AlmaLinux and Rocky Linux.

CentOS Versions and Releases

Throughout its development history, CentOS has undergone several major version upgrades. The first release, CentOS 3, was launched in 2004, and subsequent versions aimed to provide a stable and reliable environment for enterprise workloads.

Each release introduced improvements in:

- System performance

- Hardware compatibility

- Software management tools

- Enterprise features

These versions served a wide range of users—from individuals to large organizations.

However, after Red Hat’s strategic transition to CentOS Stream, traditional CentOS releases gradually moved into end-of-life status or were replaced by community-driven alternatives.

As a result, selecting the right platform—whether CentOS Stream, AlmaLinux, or Rocky Linux—has become an important consideration for organizations seeking long-term system stability.

In practice:

- Traditional CentOS releases are preferred for highly stable environments.

- CentOS Stream is better suited for testing and previewing future RHEL updates.

This distinction helps developers and system administrators choose the most suitable platform based on their operational needs.

Key Advantages of the CentOS Operating System

1. Exceptional Stability

CentOS is well known for its high reliability and minimal system errors, making it ideal for enterprise server environments.

Since it is derived from RHEL, CentOS inherits many enterprise-grade features, including:

- RPM package management

- Flexible package repositories

- Advanced system administration tools

These capabilities allow administrators to monitor, maintain, and scale systems efficiently while minimizing downtime.

2. High Compatibility

CentOS offers excellent software and hardware compatibility with RHEL, allowing enterprise applications to run smoothly on the platform.

Additionally, many popular automation and configuration management tools support CentOS, including:

- Ansible

- Puppet

- Chef

This compatibility makes CentOS highly suitable for data centers and large-scale web services where system consistency and reliability are critical.

3. Strong Community Support

The CentOS community has historically been active and collaborative, providing extensive resources such as:

- Documentation

- Technical forums

- Troubleshooting guides

Community contributions help improve security, fix bugs quickly, and maintain updated patches, ensuring the operating system remains secure and reliable.

4. Cost Efficiency

From a cost perspective, CentOS is an extremely economical solution. It provides enterprise-level features comparable to commercial operating systems, yet remains completely free.

This makes CentOS particularly attractive for organizations seeking to reduce infrastructure costs while maintaining high system performance and reliability.

Limitations of CentOS

Despite its strengths, CentOS also has several limitations that users should consider.

1. Uncertain Long-Term Development

Red Hat’s decision to focus on CentOS Stream instead of maintaining traditional CentOS releases has raised concerns about long-term stability for organizations relying on legacy versions.

For mission-critical systems, this uncertainty can be a significant drawback.

2. Declining Traditional Community Support

Following the shift to CentOS Stream, the traditional CentOS user community has gradually declined.

This has led to reduced support, fewer updates, and limited troubleshooting resources for legacy CentOS systems.

3. Increased System Management Complexity

In some cases, administrators may find it more difficult to locate updated documentation or compatible solutions, especially when managing older CentOS environments.

The lack of officially maintained stable releases can also create concerns about long-term maintenance.

4. Potential Security Concerns

Because traditional CentOS versions rely on older, stable software packages, updates for newer technologies may arrive slowly.

This can create potential security challenges or limit access to the latest software features. Administrators must therefore implement proactive security strategies to maintain system safety.

Who Should Use CentOS?

CentOS is particularly suitable for:

- Businesses and organizations seeking reliable server infrastructure

- Developers who require a stable Linux development environment

- Data centers needing predictable and consistent operating systems

- Organizations with limited budgets that still require enterprise-grade Linux systems

It is commonly used for:

- Web hosting servers

- Data storage systems

- Network services

- Enterprise backend infrastructure

However, organizations that require frequent updates and the latest software technologies may prefer alternatives such as Ubuntu Server or newer RHEL-based distributions.

Basic CentOS Commands

When working with CentOS, familiarity with essential command-line tools is critical for effective system administration.

Some commonly used commands include:

yum

In earlier CentOS versions, yum is used for package management, allowing users to install, update, and remove software.

Example:

yum install nginx

This command installs the Nginx web server.

systemctl

The systemctl command is used to manage system services.

Examples:

systemctl restart nginx

systemctl status nginx

These commands restart the service or check its status.

firewalld

The firewalld service manages system firewall rules to enhance security.

ss or netstat

These commands allow administrators to monitor active network connections, helping ensure system stability and security.

Other Essential Commands

Additional administrative commands include:

- adduser – create new users

- chmod / chown – manage file permissions and ownership

- df -h – check disk usage

Understanding these commands helps administrators manage and maintain CentOS systems efficiently.

How to Install CentOS

Installing CentOS is relatively straightforward but requires proper preparation.

Step 1: Download the ISO

Download the CentOS ISO file from official or trusted sources. Then create a bootable USB drive or burn the image to a DVD.

Before installation, verify that your system meets the minimum hardware requirements.

Step 2: Configure Installation Settings

During installation, users must configure:

- Language selection

- Disk partitioning

- Network configuration

- User accounts

Administrators should also choose the appropriate installation mode:

- Minimal installation for lightweight system

- Full installation for environments requiring more features

Step 3: Configure Networking and Security

Network settings such as static or dynamic IP addresses should be configured during installation to ensure stable operation.

Users can also select default services or customize configurations based on system requirements.

Step 4: Post-Installation Setup

After installation, the system should be updated and required software packages installed.

This step ensures the operating system is ready for production use.

The Future of CentOS

Following the shift to CentOS Stream, the platform now acts as a preview distribution for upcoming RHEL releases.

This model allows the community to anticipate future developments within the Linux ecosystem and prepare for upcoming updates.

However, the faster development cycle also introduces challenges related to stability and predictability compared with traditional CentOS releases.

In response, new projects such as AlmaLinux and Rocky Linux have emerged as alternatives. These distributions aim to maintain the original goal of CentOS by providing free, stable, RHEL-compatible Linux platforms.

These developments reflect the broader goal of the Linux community: building a sustainable and adaptable open-source ecosystem capable of meeting evolving technology demands.

Conclusion

In summary, CentOS is an open-source Linux operating system derived from Red Hat Enterprise Linux, known for its stability, security, and flexibility.

For more than a decade, CentOS has served as a reliable platform for enterprise servers, organizational infrastructures, and open-source development communities.

Although Red Hat’s transition to CentOS Stream introduced a new direction for the project, the broader ecosystem continues to evolve through alternative RHEL-compatible distributions such as AlmaLinux and Rocky Linux.

By understanding CentOS’s core features, installation process, advantages, and limitations, users can make informed decisions about the most suitable operating system for their infrastructure needs.

CentOS and its successor ecosystems remain an essential part of the diverse and expanding Linux landscape.