Surprising reasons why CentOS users feeling stranded turn to Oracle Linux

April 24, 2021 | 4 minute read
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Hint: Oracle Linux is compatible and free to download, free to use in development and production, and free to redistribute. That means free source code, free binaries, free updates, free errata — all without having to commit anything to Oracle.

This post is thanks to: Alexa Weber Morales


When it comes to running an operating system, a good day is when nothing remarkable happens. It takes engineering savvy to make that come true, however. For the last 15 years, there’s been an enterprise Linux distro that is regarded for its performance, stability, and security. Now it’s back in the spotlight thanks to IBM/Red Hat’s recent change of plans for CentOS 8.

Cutting CentOS’s presumed lifespan short by years stranded users, many of whom who are now wondering where to turn for a quality Linux distribution that is compatible with Red Hat Enterprise Linux (RHEL). “Last December, IBM announced that they were going to end-of-life CentOS as we know it, and they created a new upstream distro called CentOS Stream, which provides a rolling preview of features for RHEL,” says Robert Shimp, Group Vice President for Infrastructure Software Product Strategy. “That's not quite the same as the traditional role of CentOS as a downstream, free distribution. That switch has created a lot of uncertainty about where CentOS users are going to move.”

But there are options, and one of them is the backbone of Oracle’s own cloud: Oracle Linux, a RHEL-compatible distribution used by businesses (like Alior Bank) and institutions (like the NASA’s Jet Propulsion Laboratory). So, what are the differences? “If you write an application you can run it on RHEL, CentOS, or Oracle Linux just fine — but Oracle Linux goes considerably further than CentOS. We provide a lot of engineered features, most especially around enterprise availability and security,” says Shimp.

Patching while running

One example is Ksplice [Oracle Ksplice introduces Known Exploit Detection functionality], an online patching feature that can update critical patches for both Oracle Linux’s kernel and for key user space libraries such as glibc, OpenSSL, as well as Oracle Linux’s built-in KVM hypervisor. That means you can keep production systems up and running while patching them, without taking anything offline or doing any reboots, says Shimp. “That's been a huge advantage. We’ve had hundreds of millions of updates done by customers with Ksplice and it's just wildly popular.”

Oracle also uses Ksplice for its own infrastructure when critical security flaws like Spectre and Meltdown emerge, Shimp explains: “When those happened, of course Oracle uses Oracle Linux itself within its cloud, and we have hundreds of thousands of servers in dozens of data centers around the globe. We were able to patch all of those zero day flaws from Spectre and Meltdown overnight. We rolled that out globally without users even being aware, no problem.”

Another cool tool included with Oracle Linux is DTrace, a comprehensive, open source, dynamic tracing framework available to Oracle Linux users. DTrace is designed to give operational insights that allow users to tune and troubleshoot the operating system. It provides developers with a tool to analyze performance and increase observability into systems, to see how they work. DTrace enables higher quality applications development, reduced downtime, lower cost and greater utilization of existing resources.

The switch is easy

A handy GitHub script [Switching from CentOS to Oracle Linux: a hands-on example] launches the change from CentOS to Oracle Linux, which takes as little as five to 10 minutes, says Shimp: “Basically, you leave your CentOS in place, and just point your updates to our Yum repository at And you begin receiving the Oracle updates on top of your existing image.” Is there a gotcha? Oracle Linux has always been free to download, use, and re-distribute, according to Shimp, with no obligation to purchase support. There’s no limitation on the number or size of systems.

Oracle is consistently one of the top contributors in the vibrant Linux community — so what kinds of contributions has Oracle made? “We’ve made major code contributions such as Oracle Cluster File System and the Btrfs file system, and much more. Oracle’s Linux engineering team is a trusted part of the Linux community and several Oracle employees are Linux mainline kernel maintainers. Beyond contributions to Linux, we drive a lot of other open source projects such as MySQL and VirtualBox.”

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It’s more than an OS

That variety of open source technologies reminds Shimp of one of the key differentiations of Oracle Linux versus CentOS: It’s more than an operating system, it’s a complete operating environment. “Not only do you get the RHEL-compatible Linux operating system, you're getting the KVM hypervisor, you're getting Kubernetes and containers and other cloud native functionality, all integrated together and tested together.”

“It’s been our direction since 2006, and we keep making enhancements,” says Shimp. “We intend to keep this going far into the future.”



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