Adding kernelopts in GRUB 2 with Ansible

grub2-kernelopts.yml

# set kernel option via grub2
# (e.g. to disable THP in EL8+)
#
# N.B. this code doesn't support updating the value of an existing setting (not fully idempotent);
# in that case it will add a duplicate entry that may or may not override the first.
# If you have a lot of settings to manipulate, it would be easier to explicitly override the entire kernelopts
# (or use regex_replace)
#
# assumes thp_setting contains the sysfs value for THP
#
- name: get kernel args
  command: grub2-editenv - list
  changed_when: false
  check_mode: no
  register: grubenv
  when: ansible_distribution_major_version|int >= 8

- name: disable THP in kernel args
  shell: |
    grub2-editenv - set "{{ grubenv.stdout_lines | select('match', 'kernelopts=') | list | first }} transparent_hugepage={{ thp_setting }}"
  when: ansible_distribution_major_version|int >= 8 and ("transparent_hugepage=" + thp_setting) not in grubenv.stdout