Red Hat, CentOS or Oracle Linux?

Written by Jobin Joseph

Jobin Joseph is the Information Systems Manager.

Well... many Enterprise System Administrators ask me, which Linux OS should I use for my Linux environment?? Red Hat Enterprise Linux (RHEL), Community ENTerprise OS (CentOS) or the Oracle Enterprise Linux (OEL).

Let's see how these Operating Systems are developed and what are the main features you should consider before selecting one!

RHEL – Red Hat Enterprise Linux

Red Hat is the leading commercial contributor to the Linux® kernel. The Open Source company, the Leader in Linux Distribution releases the Enterprise OS Red Hat Enterprise Linux. Each Kernel release is tested on different hardware platforms and it gets certified by different Hardware vendors.

Red Hat maintains relationships with thousands of software and hardware vendors to certify the performance of the business-critical applications on Red Hat and JBoss® software. You gain access to this ecosystem—one of the largest technology certification ecosystems in the world, with more than 4,000 product certifications to date and more being added every day. No derivative of Red Hat technology enjoys these certifications and third-party support.

Is RHEL free?

Yes, but not really, You can download and use the RHEL ISO to install RHEL for your servers. There are no issues, but you won't get any update for the OS!

If you don't have the RHEL iso with you, you can request an evaluation from the below link for the same.

Why I need the updates – The ISO comes with the most stable packages, Red Hat will be releasing security updates frequently for any CVE reported and makes it available via their Red Hat Network Satellite. These updates are only available with a paid Subscription.

Subscription / License

There are different Subscription models for Red Hat. Self Support, Standard and Premium. You can choose any of it based on the SLA and support you require from Red Hat Global Support. It is guaranteed that the person who attends your issue is an RHCE (Red Hat Certified Engineer).

All of the subscriptions are coming with FREE RHN access. That means you can register the server with RedHat for any updates.

CentOS – Community Enterprise OS

The CentOS Linux distribution is a stable, predictable, manageable and reproducible platform derived from the sources of Red Hat Enterprise Linux (RHEL).

Since March 2004, CentOS Linux has been a community-supported distribution derived from sources freely provided to the public by Red Hat. As such, CentOS Linux aims to be functionally compatible with RHEL. CentOS mainly changes packages to remove upstream vendor branding and artwork. CentOS Linux is no-cost and free to redistribute.

Unlike RHEL, with CentOS, You have access to the CentOS repo, No Server registration is required for updates. Once a bug fix is released by RedHat it will be available to CentOS as well. You can simply update the OS  through yum to apply the patches just like in Red Hat.

What is the Difference between CentOs and RHEL then?

Lack of Vendor Support! Yes there is no dedicated support for CentOS, but there is a community for the support but you never guarantees that the fix will be available in say 24 hrs.

If you represent a small organization, and you are not running any Mission critical application on your servers, Then you can go for CentOS. Because small companies won't have the budget for buying OS subscription and also they will be getting a stable Operating System for the server.

OEL – Oracle Enterprise Linux

Oracle Enterprise Linux, as I stated RHEL source code is free, So Oracle downloads the source code and then compile it with few changes and releases those packages at their ULN (Unbreakable Linux Network)

Just like CentOS, Oracle is also giving updates via their public yum server No registration is required to get these updates. You can use this just like CentOS. You have access to all the updates from that repository. (Wait, Keep in mind that these updates are provided by Red Hat first. Then when Red Hat makes it public, Oracle copies it to their Repository.)

Like Red Hat, Oracle also has different Subscriptions. Like Repo only access, Repo access + Ticket Support, Repo access + Ticket + Telephonic Support.  So, If you have a valid ULN subscription from Oracle, You can register the server with Oracle network and you can see the registered server by logging in to your account.

What is EUK – Enterprise Unbreakable Kernel?

All the Linux Kernel versions are certified by different hardware vendors. When Oracle alter the kernel and rename it to EUK kernel, you are losing all the hardware and application certification the original kernel / RHEL has.  Also, I have personally experienced an issue with one of our customer who had installed a paid Antivirus on OEL and they ran into many issues. When they checked with the Antivirus support, they clearly said that UEK kernels are not supported. So, they had to switch to the Default kernel to get it working.

Conclusion: Need my Advice?

If you are a Small organization (Not a Bank, ISP or Ministry) who can't spend money on the Operating System Licenses /  Subscription, and you still need an Enterprise Operating System, then go for CentOS. You will be using the clone of RHEL, You have the same updates as of  Worlds #1 Linux distribution RHEL.

– If you represent a large Organization with mission-critical servers, or you are a Bank, ISP, Ministry or any other Government organization, Then never go for an alternative such as CentOS or OEL, Just go for Red Hat Enterprise Linux server which offers Hardware Certifications and Vendor support. You will be using the world’s #1 Linux distribution with full support from the Vendor.

- If your Application Team / DBA says that he need OEL, please ask him to check with Oracle about RHEL compatibility for his application/database. If it is supported, go for RHEL, otherwise... bad luck... go for OEL.

If you have any comments on this, please drop it here.

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