CentOS Hyperscale SIG Quarterly Report for 2021Q4

Monday, 10, January 2022 Davide Cavalca SIG No Comments

CentOS Hyperscale SIG Quarterly Report for 2021Q4

This report covers work that happened between October 2nd and December 31st. For previous work, see the 2021Q3 report.


The Hyperscale SIG focuses on enabling CentOS Stream deployment on large-scale infrastructures and facilitating collaboration on packages and tooling.

Membership update

Since the last update, the SIG gained two new members (Jack Aboutboul and David Duncan).

We welcome anybody that’s interested and willing to do work within the scope of the SIG to join and contribute. See the membership section on the wiki for the current members list and how to join.

Releases and Packages

Unless otherwise specified, packages are available in our main repository, which can be enabled with dnf install centos-hyperscale-release. Please report any issues with these packages on our package-bugs tracker.

CentOS Stream 9

CentOS Stream 9 is now available and Hyperscale tags have been setup in CBS to build and release packages for it. As of now, we have released systemd and kpatch in our main repository, plus btrfs-progs and a kernel in our experimental repository. We have more packages and features targeting CentOS Stream 9 specifically planned for the near future. Going forward, we expect to continue building packages for both CentOS Stream 8 and CentOS Stream 9 in parallel.

The SIG also emphasizes contributing to CentOS Stream 9 itself whenever possible. As a result, SIG members have made several improvements to CentOS Stream 9.

The Hyperscale SIG is responsible for the following features in CentOS Stream 9, most of which have been contributed in the last quarter:

These features have been partially or fully developed by SIG members in Fedora Linux and backported to CentOS Stream 9 for the benefit of the Enterprise Linux community.


We have continued fleshing out our user documentation website. Among other things, we have added an explicit versioning policy for our packages, documented our systemd release process and compiled a reference list of Hyperscale-related conference talks.

As previously mentioned, we would very much welcome any feedback and contributions you might have for this documentation.


The latest version in the Hyperscale SIG continues to be systemd 249. Since the last update we have re-enabled systemd-repart and backported a fix for BPF cgroup controller realization. We now also compile systemd without support for iptables, thus defaulting to nftables, in line with the Fedora packaging. This has allowed us to create builds of systemd 249 for CentOS Stream 9.

In order to support systemd builds, our meson backport has also been updated to 0.58.2.

Compression libraries

We have branched and updated lz4 to 1.9.3 and zstd to 1.5.0. Because these libraries are ABI and API compatible, we were able to push these updates without requiring additonal rebuilds of downward dependencies.


CentOS Stream 9

Neal Gompa has started building an experimental kernel for CentOS Stream Hyperscale 9 based on the CentOS Stream/RHEL 9 kernel sources. Initial kernel builds have been released to the experimental repository. As part of this effort, he has been working with the RHEL kernel developers on developing the workflow for external (that is, non-Red Hat) contributors and has begun contributing to the RHEL kernel.

We are also collaborating with the CentOS Kmods SIG to assist in enablement of the necessary support modules in the RHEL kernel to offer Btrfs as a kernel module package for RHEL 9, for those using RHEL 9 or derivatives and need the official RHEL kernel. As part of this, we intend to contribute community maintenance of Btrfs in the RHEL kernel tree for our kernel and the Kmods SIG to carve out and build as a kernel module package.

CentOS Stream 8

The CentOS 8 kernel has remained at 5.12 while Justin Vreeland looks into issues showing up in the bpf selftest during aarch64 builds. Justin plans to have it sync’d with the CentOS Stream 9 kernel Neal has been working on by the end of Q1 2022.

Live media

We started work on getting the necessary image build tools shipped in EPEL 9 to start offering live media based on CentOS Stream 9. The livecd-tools package is currently blocked on dumpet, which has a stalled package branch request for EPEL. The appliance-tools package is blocked on livecd-tools in EPEL. The kiwi package is currently blocked on Red Hat shipping mtools on all architectures. This should be resolved once the next CentOS Stream 9 compose is released and imported into Fedora Koji for EPEL 9.

DNF/RPM stack with CoW support

We have rebased the Copy-on-Write packaging stack in the experimental repository to match the latest updates that landed in CentOS Steam 8 proper.

Health and Activity

The SIG continues to maintain a healthy development pace.


The SIG holds regular bi-weekly meetings on Wednesdays at 16:00 UTC. Meetings are logged and the minutes for past meetings are available.

The SIG uses the #centos-hyperscale IRC channel for ad-hoc communication and work coordination, and the centos-devel mailing list for async discussions and announcements. The SIG also holds open monthly video conference sessions to promote collaboration and social interaction.

Conference talks

Last quarter, Davide Cavalca and Neal Gompa presented an update on SIG activities at CentOS Dojo, October 2021 (slides, video). Hyperscale SIG work was also covered in Building the future with CentOS Stream at the Red Hat mini-theater during Supercomputing 2021.

This year, we’ll be presenting another update on SIG activites at CentOS Dojo, FOSDEM 2022. SIG-adjacent talk proposals have also been submitted to DevConf.cz 2022 and SCALE 19x.

Planned work

The SIG tracks pending work as issues on our Pagure repository. Notable projects currently in flight include:

Issues for the Board

We have no issues to bring to the board’s attention at this time.

Leave a Reply

Your email address will not be published. Required fields are marked *