---
# Warning! These tasks can result in lost data. Take care when developing and
# using them.

# Initialisation tasks to be applied on first boot of a system to initalise
# disks. We search for block devices that are not currently mounted, then wipe
# any LVM or file system state from them.

- name: Ensure LVM2 is installed
  yum:
    name: lvm2
    state: present
  become: True

- name: Check for unmounted block devices
  shell: >
    lsblk -i -o NAME,MOUNTPOINT   | awk \
        '/^ *[|`]-/ && NF > 1 { mounts[master_dev] = mounts[master_dev] $2 " " }
         /^sd/ && NF == 1     { master_dev = $1; mounts[master_dev] = "" }
         END                  { for (dev in mounts) if (mounts[dev] == "") print dev }'
  register: unmounted_devices
  changed_when: False

- name: Ensure that all unmounted block devices have LVM state removed
  shell: |
    set -e
    if pvs /dev/{{ item }} >/dev/null 2>&1
    then
        echo "Found PV on /dev/{{ item }}"
        vg=$(pvs --noheadings -o vg_name /dev/{{ item }})
        if [[ -n $vg ]] && [[ $vg != "    " ]]
        then
            echo "Found VG $vg on PV /dev/{{ item }}"
            lvs --noheadings -o lv_name $vg | while read lv
            do
                if [[ -n $lv ]] && [[ $lv != "    " ]]
                then
                    echo "Found LV $lv on VG $vg. Removing"
                    lvremove -yf ${vg}/${lv}
                fi
            done
            vgremove -f $vg
        fi
        pvremove -yff /dev/{{ item }}
    fi
  with_items: "{{ unmounted_devices.stdout_lines }}"
  become: True

- name: Ensure that all unmounted block devices have filesystems wiped
  command: "wipefs -f /dev/{{ item }}"
  with_items: "{{ unmounted_devices.stdout_lines }}"
  become: True
  # The command can fail in some cases which are valid, so ignore the
  # result.
  failed_when: False

- name: Ensure that all unmounted block device headers are zeroed
  command: "dd if=/dev/zero of=/dev/{{ item }} bs=1M count=100"
  with_items: "{{ unmounted_devices.stdout_lines }}"
  become: True