- hosts: all
  gather_facts: true
  vars:
    remount_state: ro
    remount_fs:
    - /
    - /usr
    - /opt
  tasks:
  - name: remount filesystems
    command:
      mount -oremount,{{ remount_state }} {{ item }}
      warn=false
    with_items: >-
      {{
      ansible_mounts
         | selectattr('mount', 'in', remount_fs)
         | map(attribute='mount')
         | list
      }}