since some days containers in OBS using the Dockerfile fail to fail to resolve due to

``` have choice for product_flavor(openSUSE) needed by openSUSE-release: openSUSE- release-appliance-custom openSUSE-release-appliance-docker openSUSE-release- appliance-hyperv openSUSE-release-appliance-kvm openSUSE-release-appliance- openstack openSUSE-release-appliance-vagrant openSUSE-release-appliance-vmware openSUSE-release-appliance-wsl openSUSE-release-ftp ```

If I set `Prefer: openSUSE-release-appliance-docker` in the project config I get

``` error running container: error creating container for [/bin/sh -c obs-docker- support --install]: time="2019-10-27T15:23:32Z" level=error msg="systemd cgroup flag passed, but systemd support for managing cgroups is not available ```

e.g. in https://build.opensuse.org/package/live_build_log/ home:okurz:container/yamllint/containers/x86_64

This is reproducible also when creating a new project based on the wizard following https://build.opensuse.org/image_templates selecting "Templates using openSUSE Tumbleweed", "Container built using docker tool".

By comparison, a container built based on Leap 15.1 seems fine: https:// build.opensuse.org/package/show/home:okurz:branches:openSUSE:Templates:Images: 15.1/container_test

Any ideas how to fix the container build using Dockerfile?

Have fun, Oliver