What About The AltArch Repositories? (+ Some Experiments With Aarch64 On Raspberry Pi)

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Hello,

given the recent change in direction of CentOS, what will become of the AltArch repositories? (like CentOS 7 aarch64 and the related kernel repositories)

I have been experimenting (with some success) with running a regular CentOS
8 aarch64 (ARM 64 bits) on a Raspberry PI 4 (with 4GB RAM), using the aarch64 kernel-rpi2 provided by CentOS 7 AltArch [1]. (a few more technical details below)

This is a very different question than what is currently hotly discussed on this list, with the end of the bug-for-bug clone of RHEL, as there were never expectations that such settings would be supported. But on the other hand, I liked to use CentOS for innovation in a given field (mostly Java related) as its stability allowed one to go deep into one direction with
“other things being equal” (contrary to Fedora, which is always moving in all directions).

I guess that all these “side projects” (and SIGs, etc.) will disappear as well, won’t they?

Cheers,

Mathieu

## More details about running CentOS aarch64 on a Raspberry Pi 4

As for my experiments with running CentOS 8 on a Raspberry Pi 4, a bit more details, so that these efforts are not completely lost. Two approaches were working :

– From a plain CentOS 7 AltArch aarch64 installation, perform a CentOS 8
aarch64 install in a chroot (with the –installroot option) + a clean kernel-pi2 install from the CentOS 7 kernel-pi2 repository. Then copy the chroot to an .img file, and use this image to initialise an SD card.

– From a plain CentOS 7 AltArch aarch64 installation, perform an in-place upgrade to CentOS 8 (first install dnf from EPEL, then switch the repos, and it works)

The second approach had better device support on the Raspberry Pi 4 (most importantly the wifi, which was not working with the first approach), but this was probably a matter of subtle kernel / modprobe configs that were beyond my skills. I thought that I would share all this at some point, and ask for help from the CentOS AltArch developers; but I guess it is irrelevant right now.

Both approaches were working equally well on the Raspberry Pi 3 (but Fedora support is good for this version, while Raspberry Pi 4 is not supported, so I tend to use Fedora aarch64 on them).

As for what is actually the point of doing all this, this is not for weekend hobby tinkering, and it is relevant for server-side applications. ARM 64 bits is becoming an important platform (hence the fact that RHEL is now supporting it, MacOS will soon completely move to it, etc.) especially if one is interested in climate-friendly low-power IT, also on the server-side. But finding hardware is not easy and the (cheap) Raspberry Pi have 64-bit capable processors, even though the default distrib (Raspbian, based on Debian) does not yet support 64 bits (but they are working on it
[2]). After trying many distributions, a paradox was that CentOS was actually the easiest to deploy and use in order to get some results (thanks to the work of the AltArch team!)

In my case, the main interest was to test on ARM 64 bits GraalVM, the next generation Java platform, which can compile Java (and other programming languages) to native code. These builds require a lot of memory, but with an extremely slimmed down CentOS 8 and the 4 GB memory of the Raspberry Pi
4, it worked! [3]

On a different layer, I could also test Eclipse SWT (Java user interface library) on this architecture (but on the plain CentOS 7 aarch64 with GNOME), and provide some quick feedback to Eclipse developers on their recent support for the whole Eclipse IDE on ARM 64 bits. [4]

[1] http://mirror.CentOS.org/altarch/7/kernel/aarch64/kernel-rpi2
[2] https://downloads.raspberrypi.org/raspios_arm64/images/
[3] https://twitter.com/mbaudier/status/1274263320254722050
[4] https://twitter.com/mbaudier/status/1291421892381937670

6 thoughts on - What About The AltArch Repositories? (+ Some Experiments With Aarch64 On Raspberry Pi)

  • I asked about this before. As far as CentOS itself is concerned this is an unknown. For me it’s kind of annoying because I just set up a couple of Raspi 4’s with CentOS 8 for a home automation system right before this announcement was made.

    Having said that- there is a little known distro called “RedSleeve Linux”. It’s just a couple of guys who do builds of RHEL 6, 7, 8
    specifically for ARM systems. I contacted those guys because I did some work with them in the past, and I suggested they work with the folks at RockyLinux to combine efforts.

  • It’s also worth noting that there is a CentOS 8 SD Card image for Raspberry Pi 4. That’s what I used. It was dirt simple to “install”-
    simply dd the image file to an actual SD card, put it in the RasPi, and go! (Allthough in my case, I made some modifications to the filesystems before actually booting. I made the filesystems bigger and I removed journaling from them.)

  • Do you mean an image for armhfp (32 bits) or for aarch64 (64 bits) ?
    Could you please send a link? Thank you!