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Next steps to consider before CentOS 7 end of life

In today's world of security threats, it's critical to keep OSes up to date. As the end-of-life date for CentOS 7 approaches, companies can no longer delay distribution migration.

CentOS 7 reaches end of life on June 30, 2024. This leads to complications for the many organizations that still rely on CentOS deployments, making it critical to replace these systems right away.

The EOL date represents the end of maintenance, which means no further security or functional updates will be available and no additional development will occur. Companies must get installations into their update cycle right away to stay on top of feature and security enhancements.

CentOS EOL explained

The CentOS Linux distribution, a nearly identical alternative to RHEL, was a way to run RHEL systems without the additional weight of the subscriptions and other licensing challenges the enterprise-oriented distribution carried with it.

While RHEL brought many benefits, including support, CentOS served as an alternative for developer systems, test servers and various other places in the enterprise where simple but powerful deployments were needed.

Back in December 2020, Red Hat announced the end of CentOS Linux 7. The reasons for its termination include the following:

  • CentOS took sales opportunities from RHEL by being a free but powerful alternative.
  • Red Hat had the chance to move CentOS from a downstream version to an upstream development platform.
  • Red Hat teams and customers were confused over CentOS' placement in the sales and support model.

A recent Lansweeper article indicated that around 26% of the Linux systems that it had data on ran CentOS. That statistic placed it ahead of the always-popular Ubuntu Linux distribution and RHEL among the machines. It's impossible to know how many installations exist worldwide.

Will CentOS Linux 7 still run after its EOL?

The EOL, or end of maintenance, concept does not mean that CentOS Linux simply turns off or can no longer be used. It means the vendor will no longer offer new features, correct security flaws and update performance options. That's not a significant short-term problem, but it is a serious long-term one. Today's security threats are enough reason to have concern with a vendor that no longer provides patches. Performance and other implications are also of concern.

CentOS 7 users can still run their systems after the EOL date, but it's not recommended. However, some users may have old applications that they can't port to a different distribution.

What about CentOS Stream?

CentOS Stream is an upstream version of RHEL, where new features are tested that may find their way into later RHEL versions.

The older CentOS Linux was a downstream version of RHEL and Fedora, which means that it had to wait for new features until they were integrated into the other distributions. CentOS Linux also followed RHEL's predictable release cycle, which is important and useful to enterprises. CentOS Stream maintains a rolling release cycle to reflect its more nimble and test-oriented purpose. CentOS Stream also enables direct community contributions, while CentOS Linux did not have a contribution scheme. The following is the status for different CentOS Stream versions:

  • CentOS Stream 8 end of builds. As the upstream version of RHEL 8, CentOS Stream 8 has reached its natural conclusion. Users should consider migrating to CentOS Stream 9.
  • CentOS Stream 9. This is the current CentOS Stream version that serves as the upstream distribution for RHEL 9.

CentOS Stream may be a viable option for some enterprise deployments. However, Red Hat moved CentOS Stream to an upstream RHEL version with a rolling release schedule of more experimental features, which makes it a less predictable choice. So, with CentOS Linux no longer being patched and CentOS Stream being a less viable alternative, companies need to develop a plan to replace those systems.

CentOS alternatives

Numerous distributions are available as replacement options for CentOS Linux. The four most similar distributions to CentOS 7 are AlmaLinux, RHEL, Rocky Linux and SUSE Linux Enterprise Server (SLES).

SLES uses the Zypper package manager, while AlmaLinux, RHEL and Rocky Linux all use the same package managers -- RPM Package Manager and Yellowdog Updater Modified/Dandified YUM -- for software maintenance. They also retain similar file, feature and service functionality, offering comfort and familiarity. Organizations should explore these choices now to have an alternative for when CentOS 7 is no longer beneficial to the company.

Many distributions are similar at their core. The end of CentOS enables an opportunity for your company to consolidate systems and concentrate on maintaining fewer distributions.

Immediate actions

Many distributions are similar at their core. The end of CentOS enables an opportunity for a company to consolidate systems and concentrate on maintaining fewer distributions.

Begin by identifying the CentOS 7 deployments in the environment. Next, select a replacement distribution, paying particular attention to AlmaLinux, Rocky Linux, RHEL and SLES. Consider any other distributions ripe for replacement and make effective use of virtualization where possible.

After selecting an alternative distribution to CentOS, follow these next steps:

  1. Identify all CentOS installations.
  2. Identify all applications to migrate.
  3. Back up all user, application and system data.
  4. Deploy and update the new distribution.
  5. Install all applications on the new deployments.
  6. Restore data, including configurations and settings.
  7. Test the migrated systems for full functionality.

This lengthy process can be shortened with the use of tools like Lansweeper, which offers a new report to help detect CentOS deployments in the environment and ensures the user they migrated to a supported platform.

Additional opportunities

There are some additional options available during this migration phase from CentOS. Take a moment to consider whether additional streamlining benefits the environment.

Other potential migration actions include the following:

  • Bare-metal or virtualized deployments. Eliminate physical systems, and migrate their services to VMs.
  • On-premises or cloud deployments. Consider whether some services or systems might benefit from cloud hosting instead of maintaining them on premises.
  • Consolidate distributions. What other distributions does the organization support, and what challenges exist by maintaining a wide variety of Linux distributions? It might be beneficial to migrate other odd or one-off Linux installations to a chosen CentOS Linux replacement to achieve greater consistency and easier maintenance.

Migration tools

Various tools exist to help with migrations. With the end of CentOS 7 just around the corner, tools such as these are critical to a timely migration:

  • Convert2RHEL. A Red Hat tool for direct conversion from CentOS 7 to RHEL 7 with minimal disruptions.
  • Leapp. A Red Hat tool to migrate from RHEL 7 to RHEL 8 but also works for CentOS 7-to-RHEL 8 migrations -- it does not support migrating to "RHEL-like" distributions, such as Rocky Linux.
  • Elevate. An AlmaLinux utility to migrate settings and configurations from CentOS 7 to AlmaLinux 8 or 9.

Don't forget the value of clean installs to help avoid unnecessary software, old configurations and odd settings.

Damon Garn owns Cogspinner Coaction and provides freelance IT writing and editing services. He has written multiple CompTIA study guides, including the Linux+, Cloud Essentials+ and Server+ guides, and contributes extensively to TechTarget Editorial and CompTIA Blogs.

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