Welcome to Your Ultimate CentOS Guide

In this CentOS guide, we have compiled dozens of resources to help teams understand the current CentOS enterprise Linux landscape and make informed decisions on how to move forward.

You can read along or jump to the section that interests you most:

CentOS Overview

Why Was CentOS So Popular?

CentOS Linux (not to be confused with CentOS Stream) gained a lot of popularity as a Linux distribution because it was an open source distribution derived from Red Hat Enterprise Linux (RHEL). Before it was discontinued in favor of CentOS Stream, the CentOS community was critical to the development and success of CentOS Linux distributions.

Many organizations — including large enterprises — choose free and open source Enterprise Linux distributions because they offer, freedom, flexibility, and cost-savings over expensive alternatives. 

With that in mind, many teams that previously used CentOS are moving on to similar RHEL-derived distributions like Rocky Linux, AlmaLinux, or different flavors of Linux entirely.

Regardless of which Enterprise Linux distribution you choose, It’s always important to start by evaluating your open source strategy. Will you support your distro yourself? Or will you partner with a vendor for support? When backed by Enterprise Linux support, open source Enterprise Linux distributions can still offer superior security and stability to help your business deliver ROI and accelerate innovation. 

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Versions of CentOS: Guides

With recent changes to CentOS end of life, there is now only one supported version of CentOS available, CentOS 7. While it’s still possible to use CentOS 6, or CentOS 8 in production environments, doing so would require supplemental support.

Before the change, CentOS versions typically went end of life after 10 years.  As an example, CentOS 6 EOL happened on November 30, 2020.

As mentioned above, if you’re currently on an end of life CentOS version, you need to determine a support and migration strategy to avoid exposing your IT infrastructure (and business) to risk. 

Which CentOS Version Should I Use?

If you're only now considering CentOS, you should only consider CentOS 7, which will have community support until June 30, 2024. Alternatively, if your infrastructure is equipped to handle rolling releases, CentOS Stream may be a valid option.

For more information on CentOS 6, 7, 8, or Stream, be sure to browse the guides below. We also have a helpful FAQ on the CentOS 8 announcement for those who need a quick overview of what the change means.

CentOS 6

CentOS 6 reached end of life in late 2020. That means it no longer receives patches or updates from the community. For companies with EOL CentOS 6 deployments, it’s important to keep them patched against any CVEs after the EOL date and to quickly find a valid migration path to a supported distribution.

Learn More About CentOS 6 LTS From OpenLogic >>

CentOS 7

As mentioned above, CentOS 7 is currently scheduled for end of life on June 30, 2024. That means companies who have a large number of deployments should be thinking about how they’ll migrate to a new distribution before that deadline.

Given the recently slippery nature of CentOS community support end of life, having that plan in motion well before that deadline is advisable.

Watch On-Demand: Planning for CentOS 7 End of Life

Learn More About CentOS 7 Support and Services From OpenLogic >>

CentOS 8

While the CentOS 8 release brought new features and updates, (including boom, tlog, EL8, and stratis storage manager) Red Hat revised the EOL date from the previously planned December 2029 to December of 2021.

For teams with EOL CentOS 8 deployments, ensuring your deployments are patched against known CVEs and finding a suitable migration path are both top priorities.

Learn More About CentOS 8 LTS From OpenLogic >>

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CentOS Enterprise Linux Alternatives

Given the end of life announcements for CentOS from Red Hat and the CentOS community, many organizations who liked what CentOS offered are paying close attention to CentOS alternatives like Rocky Linux, AlmaLinux, and Navy Linux.

These Linux distributions are considered viable alternatives to CentOS because, like CentOS Linux, they are derived from RHEL releases. Since the decision to focus on CentOS Stream, Rocky Linux, AlmaLinux, and Navy Linux have all released minor versions that mirror RHEL minor releases.

Learn More About New Releases for CentOS Enterprise Linux Alternatives

AlmaLinux 9 and Rocky Linux 9 became available soon after the release of RHEL 9, and the viability of these distributions for enterprise use cases is no longer a question. This remains true even after Red Hat's announcement about restricting RHEL source code access. In the video below, Rocky Linux's Greg Kurtzer and AlmaLinux's benny Vasquez discuss the end of the CentOS era and how their communities and projects are evolving.

Related Resources

Comparisons: CentOS vs. Guides

When it comes to Enterprise Linux distributions, there are many comparable distributions to CentOS Linux. That’s especially true now that there are CentOS alternatives like Rocky Linux, AlmaLinux, and Navy Linux available.

But it’s still a good exercise for companies using CentOS or a CentOS alternative to consider how they compare against other distributions before deciding on a distro.

CentOS Linux vs. Red Hat, for example, was a commonly requested comparison. CentOS Linux was derived directly from RHEL releases, making it functionally equivalent to RHEL. It did, however, have a release lag (similar to what Rocky Linux and others have now) after RHEL releases. The other big point of comparison between CentOS Linux and RHEL is that CentOS is a free distribution, while RHEL is a paid distribution.

Another comparison many consider is CentOS vs. Ubuntu. While CentOS is derived from RHEL, Ubuntu is derived from Debian. The core of both is the same — Linux. But CentOS Linux (or CentOS alternatives like Rocky Linux or AlmaLinux) have some advantages for the enterprise, including security and stability.

Lastly, CentOS Linux and CentOS Stream often draw a lot of comparisons. Because CentOS Stream was labeled the successor and new focus for the CentOS community, many assumed it would be similar to CentOS. In reality, the direction of the derivation has changed with CentOS Stream. CentOS Stream is now used as the staging ground for RHEL releases, and issues updates as "rolling releases.” This release structure can make it less of a fit for enterprises not equipped to handle continuous integration and deployment.

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How Much Can You Save With Free Enterprise Linux?

Countless businesses have made successful migrations to free open source Enterprise Linux distributions — and saved big. 

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How to Use CentOS: Guides for the Enterprise

You might install CentOS on Azure for your business. So, it's important to keep up with updates on CentOS releases for Azure. CentOS 7.4, for instance, included important security updates and networking enhancements. Staying up-to-date on releases can help you decide when you need to upgrade versions. (Upgrades are easier when you partner with the OpenLogic team.)

Or you might use CentOS on AWS. One important factor to consider is AWS images. You have different options for standard or security-hardened CentOS images on AWS, as you'll learn in the video below:

Those concerned with CentOS security should be regularly patching CentOS and choose STIG- and CIS-hardened images for CentOS on AWS. Watch the video below to learn why security-hardened images are so important for the enterprise. 

As you're using CentOS in your enterprise, you can run into challenges from time-to-time. In fact, there are a couple of potential errors that could occur when using cloud init on CentOS. We put together a walkthrough for how to address and avoid these. Find out other cloud challenges and solutions in our Complete Guide to Enterprise Cloud.

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Extended Support for EOL CentOS

After June 30, 2024, all versions of CentOS will be end-of-life, meaning there will be no more updates, releases, or patches put out by the community. If you can't migrate off CentOS by that date, your deployments will be vulnerable and you could fail a compliance check.

OpenLogic's new Transitional CentOS Support can bridge the gap until you are ready to migrate to another Linux distribution.  

With OpenLogic's Transitional CentOS Support, you get:

  • LTS for CentOS 6, 7, and 8 for 5 years past end-of-life
  • Access to private repo with patches 
  • Backporting
  • Guaranteed SLAs
  • Architectural minimization
  • Multi-platform support
  • Expert guidance

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