playbook_lts_kernel.yml

---
- name: playbook_lts_kernel.yml - switch to more stable kernel
  hosts: all
  gather_facts: no
  become: yes
  vars:
    uefi_detected: false
    grub_detected: false
    systemd_boot_detected: false

  tasks:

# ----------------------------------------------------------------------------
# ----------------------  DETECTION  ---------------------------------------
# ----------------------------------------------------------------------------

# UEFI DETECTION  ------------------------------------------------------------

    - name: uefi detection
      stat:
        path: "/sys/firmware/efi"
      register: output_efi_check

    - name: set uefi_detected to true if detected
      set_fact:
          uefi_detected: true
      when: output_efi_check.stat.exists

# SYSTEMD-BOOT DETECTION  ----------------------------------------------------

    - name: systemd-boot detection
      shell: bootctl is-installed
      ignore_errors: yes
      args:
        executable: /usr/bin/bash
      register: output_bootctl_is_inst

    - name: set systemd_boot_detected to true if detected
      set_fact:
          systemd_boot_detected: true
      when: output_bootctl_is_inst.stdout == 'yes'

# GRUB DETECTION  ------------------------------------------------------------

    - name: grub detection
      stat:
        path: "/boot/grub/grub.cfg"
      register: output_grub_cfg_check

    - name: set grub_detected to true if detected
      set_fact:
          grub_detected: true
      when: output_grub_cfg_check.stat.exists

# DETECTION RESULTS AND EARLY TERMINATION OF THE PLAYBOOK --------------------

    - debug: msg="uefi_detected - {{ uefi_detected }}"
    - debug: msg="systemd_boot_detected - {{ systemd_boot_detected }}"
    - debug: msg="grub_detected - {{ grub_detected }}"

    - name: end the playbook if both grub and systemd-boot are detected
      meta: end_host
      when:
      - systemd_boot_detected == true
      - grub_detected == true

    - name: end the playbook if neither grub nor systemd-boot are detected
      meta: end_host
      when:
      - systemd_boot_detected == false
      - grub_detected == false

    - name: end the playbook if grub and uefi are detected
      meta: end_host
      when:
      - grub_detected == true
      - uefi_detected == true

# ----------------------------------------------------------------------------
# ----------------------  INSTALL  -----------------------------------------
# ----------------------------------------------------------------------------

    - name: install linux-lts
      pacman:
        update_cache: yes
        name:
          - linux-lts
      when:
          - systemd_boot_detected == true or grub_detected == true

# ----------------------------------------------------------------------------
# ----------------------  SYSTEMD-BOOT  ------------------------------------
# ----------------------------------------------------------------------------

    - name: get the path of the current default systemd-boot config file
      shell: "bootctl list | grep -m1 source | awk '{print $2}'"
      args:
        executable: /usr/bin/bash
      register: output_bootctl
      when: systemd_boot_detected == true

    - name: make a copy of the current default config file
      copy:
        src: "{{ output_bootctl.stdout }}"
        dest: /boot/loader/entries/arch_lts.conf
        remote_src: yes
        mode: '0644'
      when: systemd_boot_detected == true

    - name: change the copied config to point at lts stuff
      lineinfile:
        path: /boot/loader/entries/arch_lts.conf
        regexp: "{{ item.regexp }}"
        line: "{{ item.line }}"
      loop:
        - { regexp: '^title.+$', line: 'title   Arch Linux (linux-lts)' }
        - { regexp: '^title.+$', line: 'title   Arch Linux (linux-lts)' }
        - { regexp: '^linux.+$', line: 'linux   /vmlinuz-linux-lts' }
        - { regexp: '^initrd.+$', line: 'initrd  /initramfs-linux-lts.img' }
      when: systemd_boot_detected == true

    - name: add sort-key to the config to move the lts boot menu entry to the top
      lineinfile:
        path: /boot/loader/entries/arch_lts.conf
        line: 'sort-key arch'
      when: systemd_boot_detected == true

    - name: set the lts config as default
      lineinfile:
        path: /boot/loader/loader.conf
        line: 'default arch_lts.conf'
      when: systemd_boot_detected == true

    - name: make a copy of the arch_lts to create fallback initramfs version
      copy:
        src: /boot/loader/entries/arch_lts.conf
        dest: /boot/loader/entries/arch_lts_fallback.conf
        remote_src: yes
        mode: '0644'
      when: systemd_boot_detected == true

    - name: change in the fallback config initramfs path
      lineinfile:
        path: /boot/loader/entries/arch_lts_fallback.conf
        regexp: '^initrd.+$'
        line: 'initrd  /initramfs-linux-lts-fallback.img'
      when: systemd_boot_detected == true

    - name: remove sort-key from the fallback config, to prevent fallback being top in boot menu
      lineinfile:
        path: /boot/loader/entries/arch_lts_fallback.conf
        line: 'sort-key arch'
        state: absent
      when: systemd_boot_detected == true

# ----------------------------------------------------------------------------
# ----------------------  UNINSTALL REGULAR KERNEL  ------------------------
# ----------------------------------------------------------------------------

    - name: unisntall regular linux kernel
      pacman:
        name:
          - linux
        state: absent
      when:
          - systemd_boot_detected == true or grub_detected == true

# ----------------------------------------------------------------------------
# ----------------------  GRUB  --------------------------------------------
# ----------------------------------------------------------------------------

    - name: execute "grub-mkconfig -o /boot/grub/grub.cfg"
      shell: grub-mkconfig -o /boot/grub/grub.cfg
      args:
        executable: /usr/bin/bash
      when:
      - grub_detected == true
      - uefi_detected == false