Many organisations still have servers that were installed as CentOS Linux 7 or CentOS Linux 8. Both releases are now past end of life, which means no more security updates from the CentOS Project. The systems keep running, but every month without patches adds risk, and auditors increasingly ask about it.

The good news is that there are now several solid choices. The harder part is understanding how they differ, because the differences are less about technology and more about support, governance and lifecycle. This article gives a neutral overview, at the time of writing, to help you decide.

What changed with CentOS Linux and CentOS Stream

For many years, CentOS Linux was a free rebuild of Red Hat Enterprise Linux (RHEL). It followed RHEL releases closely, so teams could run the same software without a subscription. In December 2020 the CentOS Project announced that it would focus on CentOS Stream instead. CentOS Linux 8 reached end of life at the end of 2021, and CentOS Linux 7 at the end of June 2024.

CentOS Stream is still an active, useful distribution, but its role is different. It sits just ahead of the next RHEL minor release, so it is where changes appear before they reach RHEL. That makes it a good place to test what is coming, and a less natural fit for servers that need a fixed, slowly changing platform. You can read the project’s own description on centos.org.

How the RHEL-compatible distributions differ in approach

Several distributions now fill the space that CentOS Linux used to occupy. They all aim to run software built and certified for RHEL, but each takes its own approach.

• Red Hat Enterprise Linux (RHEL) is the commercial original. You get the operating system with a subscription that includes support, certified hardware and software ecosystems, and tools for management and in-place upgrades.
• Rocky Linux is a community distribution governed by the Rocky Enterprise Software Foundation. Its stated goal is to be fully compatible with RHEL.
• AlmaLinux is a community distribution governed by the non-profit AlmaLinux OS Foundation. Since 2023 it aims for application binary interface (ABI) compatibility with RHEL rather than an exact rebuild, which lets the project ship some fixes on its own schedule.
• Oracle Linux is free to download, use and update, with paid support available from Oracle. It offers both a RHEL-compatible kernel and Oracle’s own Unbreakable Enterprise Kernel.

For most workloads, applications that run on one of these will run on the others with little or no change. The differences start to matter when a vendor certifies its product only on specific distributions, or when you rely on particular kernel features.

Support models: subscriptions, community and third-party support

The biggest practical difference between the options is who you call when something breaks. The table below summarises the main models, at the time of writing. Always check the official pages before you decide, because terms change.

Distribution	Cost to use	Where support comes from
RHEL	Paid subscription	Red Hat, included in the subscription
Rocky Linux	Free	Community, plus commercial support from third-party providers
AlmaLinux	Free	Community, plus commercial support from third-party providers
Oracle Linux	Free	Optional paid support from Oracle
Ubuntu	Free	Optional paid Ubuntu Pro and support from Canonical
Debian	Free	Community, plus commercial support from third-party providers

Free does not mean unsupported. Many organisations run community distributions in production and buy support only for the systems that need guaranteed response times. What matters is that you decide this deliberately, rather than discovering the gap during an incident.

Lifecycle and release cadence compared

Enterprise Linux is attractive because major releases are supported for a long time. RHEL major releases have a ten-year lifecycle, with options to extend it further, and Rocky Linux, AlmaLinux and Oracle Linux follow similar timelines for their matching releases. Minor releases arrive regularly within each major version, and staying on a current minor release is the normal way to keep receiving updates. Red Hat publishes the details on its RHEL life cycle page.

Ubuntu publishes a long-term support (LTS) release every two years, with five years of standard security maintenance and longer coverage through Ubuntu Pro; see the Ubuntu release cycle. Debian releases a new stable version roughly every two years, and the community Debian LTS effort extends security support for older releases; see Debian releases.

When you compare, look at the end-of-life date of the specific major version you would deploy, not just the general policy. A platform you install today should still be supported for the full planned life of the server.

Questions to ask before choosing

There is no single right answer. These questions usually bring the decision into focus:

1. Which applications do we run, and which distributions do their vendors certify?
2. Do we need a vendor support contract for every server, for some servers, or for none?
3. Do our teams already know RPM-based tooling such as dnf, or Debian-based tooling such as apt?
4. How long must the new platform be supported, and does that fit the lifecycle of the release we would deploy?
5. How do we want to manage patching, configuration and compliance across many servers?
6. Does a governance model matter to us, such as a non-profit foundation or a single commercial vendor?

For many teams leaving CentOS Linux, staying in the RHEL-compatible family keeps the most skills, scripts and packages unchanged. Moving to Ubuntu or Debian can make sense when other parts of your estate already use them, but it is a bigger change and needs more testing.

Planning the migration of existing CentOS servers

Start with an inventory. You cannot plan what you have not found, and CentOS systems are often hidden in appliances, test labs and old virtual machine templates. On each server, a few commands tell you where you stand:

cat /etc/os-release
uname -r
rpm -qa --last | head -n 20
yum repolist enabled

Then group servers by what they run and how critical they are. For each group, choose one of two paths:

• Convert in place. Within the same major version, migration scripts provided by the projects (for example for Rocky Linux, AlmaLinux and Oracle Linux) and Red Hat’s Convert2RHEL tool switch the package sources and branding without a reinstall. For CentOS Linux 7, a major version upgrade is also needed; tools such as Leapp and the AlmaLinux ELevate project can help, but they need careful testing.
• Rebuild and redeploy. Install a clean system on a current release, then move the application and data across. This takes more effort per server, but it gives you a known, documented baseline and removes years of accumulated changes.

Finally, write down the plan: which servers move, in what order, who signs off, and how you roll back. Migrating the low-risk systems first builds confidence and turns the remaining moves into routine work. The AlmaLinux project documents its ELevate approach on the AlmaLinux wiki, and each distribution publishes its own migration guides.

How LOGIQ can help

LOGIQ helps organisations find their remaining CentOS systems, compare the options against their own applications and support needs, and plan migrations that fit their schedule. If you would like a second opinion on your enterprise Linux plan, you can reach us through logiqlinux.com.