Systemd can use one of three modes in regard to how it manages cgroups:

  • legacy
  • hybrid
  • unified

How can I check which one is it using?

1 Answer 1


According to Lennart Poettering:

Try this:

stat -fc %T /sys/fs/cgroup/

if that reports "cgroups2fs" then you are in full cgroupsv2 mode. If it returns "tmpfs" then you are in either full cgroupsv1 mode, or in hybrid mode. Then, check if /sys/fs/cgroup/unified exists. If it does, then you are in hybrid mode. if not you are in pure cgroupsv1 mode.

which translates to this shell code:

[ $(stat -fc %T /sys/fs/cgroup/) = "cgroup2fs" ] && echo "unified" || ( [ -e /sys/fs/cgroup/unified/ ] && echo "hybrid" || echo "legacy")

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