---
# Check the CURRENT cgroup level; we get this from /proc/cmdline
- name: check current kernel options
  shell: fgrep systemd.unified_cgroup_hierarchy=0 /proc/cmdline
  register: result
  ignore_errors: true

- name: determine current cgroups | assume v2
  set_fact: current_cgroups=2

- name: determine current cgroups | looks like v1
  set_fact: current_cgroups=1
  when: result is succeeded

- debug:
    msg: "want: v{{ want_cgroups }}  actual: v{{ current_cgroups }}"

# Update grubenv file to reflect the desired cgroup level
- name: remove cgroup option from kernel flags
  shell:
    cmd: sed -i -e "s/^\(kernelopts=.*\)systemd\.unified_cgroup_hierarchy=.\(.*\)/\1\2/" /boot/grub2/grubenv
    warn: false

- name: add it with the desired value
  shell:
    cmd: sed -i -e "s/^\(kernelopts=.*\)/\1 systemd.unified_cgroup_hierarchy=0/" /boot/grub2/grubenv
    warn: false
  when: want_cgroups == 1

# If want != have, reboot
- name: reboot
  reboot:
    reboot_timeout: 900
  register: back_again
  ignore_errors: yes
  when: want_cgroups|int != current_cgroups|int

- name: wait and reconnect
  wait_for_connection:
    timeout: 900
  register: back_again2
  when: want_cgroups|int != current_cgroups|int and not back_again.changed

- set_fact:
    expected_fstype:
      - none
      - tmpfs
      - cgroup2fs

- name: confirm cgroups setting
  shell: stat -f -c "%T" /sys/fs/cgroup
  register: fstype

- debug:
    msg: "stat(/sys/fs/cgroup) = {{ fstype.stdout }}"

- name: system cgroups is the expected type
  assert:
    that:
      - fstype.stdout == expected_fstype[want_cgroups|int]
    fail_msg: "stat(/sys/fs/cgroup) = {{ fstype.stdout }} (expected {{ expected_fstype[want_cgroups|int] }})"