With cgroups v2 running on the host there is a change to the behavior of the docker daemon regarding cgroups:

The default cgroup namespace mode (docker run --cgroupns) is "private" on v2, "host" on v1. (cf. https://github.com/docker/docker.github.io/blob/master/config/containers/runmetrics.md#running-docker-on-cgroup-v2).

Without any changes to the docker configuration the coding in src/main/java/org/jenkinsci/plugins/docker/workflow/client/ControlGroup.java of the docker-workflow-plugin fails, since /proc/self/cgroup does no longer contain the host-cgroup for the container.

A workaround is to set the option default-cgroupns-mode to "host" for the docker daemon.

Another way of detecting the containerization is needed.