ceph-ansible/roles/ceph-common/tasks/misc/system_tuning.yml

---
- name: disable osd directory parsing by updatedb
  command: updatedb -e /var/lib/ceph
  changed_when: false
  failed_when: false

- name: disable transparent hugepage
  command: "echo never > /sys/kernel/mm/transparent_hugepage/enabled"
  changed_when: false
  failed_when: false
  when: disable_transparent_hugepage

- name: get default vm.min_free_kbytes
  command: sysctl -b vm.min_free_kbytes
  changed_when: false
  failed_when: false
  always_run: yes
  register: default_vm_min_free_kbytes

- name: define vm.min_free_kbytes
  set_fact:
    vm_min_free_kbytes: "{{ 4194303 if ansible_memtotal_mb >= 49152 else default_vm_min_free_kbytes.stdout }}"

- name: apply operating system tuning
  sysctl:
    name: "{{ item.name }}"
    value: "{{ item.value }}"
    state: present
    sysctl_file: /etc/sysctl.conf
    ignoreerrors: yes
  with_items: "{{ os_tuning_params }}"