Using cgroup v2 w/ Containers on Fedora Silverblue

I’ve been really interested in the potential behind the unified cgroup hierarchy, aka cgroup v2, in the kernel for a while now. I even helped out with a talk on this subject earlier this year. It’s worth listening to Tejun’s part of the talk if you’re not familiar with the value behind v2. While a lot of user space, for example systemd, has really solid support for v2, there have been historic gaps around virt and containers. On the virt side, initial v2 support went into libvirt 4.9 or 5.0, and it’s continuing to be improved. For containers, we’re tracking the OCI progress here and here, and Giuseppe Scrivano has done some great v2 enablement with an alternative runtime he wrote called crun. crun is basically runc re-written in C, and while there are pros and cons on the language side, it’s ridiculously fast at instantiating containers compared to runc.

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