Video : Convert CentOS to Oracle Linux

In today’s video we’ll demonstrate how to convert a CentOS installation to an Oracle Linux installation.

The video is based on this post.

The star of today’s video is Dan Norris, in a clip from a previous OpenWorld, which seems like a long distant memory now.



PS. I know I said there would be no more videos this year, but this was very much “of the moment”, so I thought it was worth doing.

Switching from CentOS 8 to Oracle Linux 8 (OL8)

If you’re a CentOS user, you’ve probably already seen Red Hat are ditching CentOS, and CentOS 8 will be the first casualty. At the time of writing Red Hat haven’t released a clear plan for what CentOS users should do. Neither Fedora or CentOS Stream are viable options for people looking for long term stability. There’s a suggestion that cut price RHEL licenses may be available in future, but all we know at this point is CentOS is on a road to nowhere.

One of the options you might want to consider is switching from CentOS 8 to Oracle Linux 8. Oracle Linux is a binary clone of RHEL, like CentOS. Also like CentOS, you can use Oracle Linux for free (downloads here), and that includes free updates.

But what do you do about your existing CentOS 8 installations? Well that’s really easy too, as you can convert them directly to Oracle Linux. Oracle have an overview of the process here, but it boils down to downloading a script from GitHub and running it. Here are the steps I used to do a conversion.

First, take a backup of the system, so you have a fallback restore point.

We display the contents of the “/etc/centos-release” file, which shows we have a CentOS 8.2 installation.

$ cat /etc/centos-release
CentOS Linux release 8.2.2004 (Core)

Download the conversion script from the Oracle GitHub repo, and run it. Then wait while it downloads the packaged as switches you from CentOS to Oracle Linux.

curl -O
sudo bash

Reboot the system.

sudo reboot

We now have an Oracle Linux server running the UEK kernel.

$ sudo cat /etc/oracle-release
Oracle Linux Server release 8.3
$ uname -r

If you don’t want to use the UEK kernel, you can switch to the Red Hat Compatibility Kernel really easily. List the current kernels.

$ ls -l /boot/vmlinuz-*
-rwxr-xr-x. 1 root root 8913656 Oct 22 22:59 /boot/vmlinuz-0-rescue-5fd85e2afa24422eb63894e2dbfa9898
-rwxr-xr-x. 1 root root 8975912 Dec 18 18:07 /boot/vmlinuz-0-rescue-caad1bd0b25943b1b526a131661074b3
-rwxr-xr-x. 1 root root 8920200 Sep 14 14:45 /boot/vmlinuz-4.18.0-193.19.1.el8_2.x86_64
-rwxr-xr-x. 1 root root 9520664 Dec 16 00:42 /boot/vmlinuz-4.18.0-240.8.1.el8_3.x86_64
-rwxr-xr-x. 1 root root 8975912 Dec 3 02:02 /boot/vmlinuz-5.4.17-2036.101.2.el8uek.x86_64

Set the latest Red Hat Compatibility Kernel as the default. It will be the highest version one without “uek” in the name.

$ sudo grubby --set-default /boot/vmlinuz-4.18.0-240.8.1.el8_3.x86_64
The default is /boot/loader/entries/caad1bd0b25943b1b526a131661074b3-4.18.0-240.8.1.el8_3.x86_64.conf with index 3 and kernel /boot/vmlinuz-4.18.0-240.8.1.el8_3.x86_64

Reboot the server.

$ sudo reboot

Now we are using the Red Hat Compatibility Kernel rather than UEK.

$ cat /etc/oracle-release
Oracle Linux Server release 8.3
$ uname -r


At this point we need to do some testing to make sure we are happy with the final result!

This type of switch may not be the preferred solution for every system, but it’s simple and saves you doing a full rebuild to switch to another distribution.

If you’re still not sure about Oracle Linux, here’s a FAQ post I wrote about it.



Happy Holidays and See You Next Year!

Just a quick post to say I’m ending the year here. I don’t plan on doing anymore videos this year, and I’m going to do my best to stay clear of social media until next year. I’ve found 2020 a very difficult ride, and probably not for the reasons you are thinking. I normally do an end of year review, but I might not this year. Better to look forward than back.

Here’s the latest batch of “.com” clips from the videos this year. Thanks to everyone who contributed.

I hope everyone has a happy holiday season, and I hope 2021 is the polar opposite of 2020.



Autonomous Database Anywhere?

I was reading about Amazon EKS Distro (EKS-D) and EKS Anywhere. For those of you not in the know, EKS stands for Elastic Kubernetes Service. What’s interesting about these new announcements is they will allow people to run EKS in Amazon AWS, on-prem and potentially in other cloud providers (Google, Azure, Oracle etc.). That got me thinking…

What if Oracle created “Autonomous Database Anywhere”? The suite of software that makes up the Autonomous Database, but packaged in a way it could be installed on-prem, but more importantly at other cloud vendors.

I happen to like the Autonomous Database product(s). It’s the start of a long journey, but I like the way it is headed. There are a couple of hurdles I see for companies.

  1. Learning to live with the restrictions of working in an Autonomous Database. When you want something done automatically, you have to give up an element of control and learn not to meddle too much.
  2. Some companies already have a big investment in “other clouds”, and won’t be jumping to Oracle Cloud any time soon.

I see the second point as a bigger stumbling block for a lot of people. Don’t get me wrong, I see the future as multi-cloud, but many companies are still in the early days of cloud adoption, and trying to jump to multi-cloud from day one may be a step to far.

I know Oracle provide alternative solutions like Cloud@Customer and Azure OCI Interconnect. Both are fine for what they set out to achieve, but neither really live up to the “Autonomous Database Anywhere” I was thinking about.

I understand the difficulties of this from a hardware, architectural, cultural and political standpoint. I just thought it was an interesting idea. Such is the way my mind wanders these days… 🙂



PS. I’m not expecting Oracle to even consider this. It was just a thought… 🙂

PPS. Oracle just released Oracle 21C Autonomous Database. Weird coincidence.

Video : Read-Only Partitions and Subpartitions in Oracle 12.2 Onward

In today’s video we’ll discuss read-only partitions and subpartitions, introduced in Oracle 12.2.

This is based on the following article.

You might find these useful too.

The star of today’s video is Chris Saxon of AskTom fame. You can check out his YouTube channel here.