(This is a duplicate of the email that went out on the mailing lists to reach more people.)
In the next stream release on the week of April 12, new nodes will use cgroups v2 by default. Upgrading systems will remain on cgroups v1.
All built-in container applications (podman, moby-engine, and crun/runc) in the next stream are now cgroups v2 capable (as of 34.20210328.1.1).
Over the coming months, our testing and stable streams will begin to use cgroups v2 for newly deployed nodes. The default change to cgroups v2 for stable will happen on or after the week of June 7th. Please test.
If you’d like to remain on cgroups v1 when deploying new nodes you can follow this example: https://docs.fedoraproject.org/en-US/fedora-coreos/kernel-args/#example….
If you’d like to opt-in early to cgroups v2 when deploying new nodes on the testing and stable streams, you can follow this example: https://docs.fedoraproject.org/en-US/fedora-coreos/kernel-args/#example…. Note that moby-engine in these streams is not yet cgroups v2 capable (requires Fedora 34 base).
If you’d like to opt-in to cgroups v2 on currently running nodes you may directly use rpm-ostree kargs as described in this example: https://docs.fedoraproject.org/en-US/fedora-coreos/kernel-args/#_removing….
Thanks,
Jonathan Lebon, for the Fedora CoreOS team