feat: Set up filesystems

Automatically set up btrfs root and data filesystem, as well as external
HDD.

This automation change assumes a layout exactly as in current bob to
function by default, can be changed to any btrfs layout with the
`btrfs_mounts` configuration option, however.

roles/filesystem/README.md

@@ -0,0 +1,38 @@
+filesystem
+=========
+
+Mounts the filesystem(s) required for bob.
+Focused on correct `btrfs` layout and mounting,
+but also mounts an external `ext4` HDD by default.
+
+Requirements
+------------
+
+This role requires a btrfs filesystem _existing_ on _any device_ that is targeted with the role (using the 'btrfs_mounts') configuration option.
+Optionally, an external HDD is required if the mount toggle is true.
+
+Role Variables
+--------------
+
+`btrfs_mounts` can be used to set up the various (top-level) btrfs subvolumes, and their later mount points in the system.
+Define an entry by giving the `uuid` of the targeted btrfs filesystem (or device), give the name of the `subvol` you intend to give, and define the `path` where it should ultimately be mounted by `fstab`.
+You can additionally provide some `opts` which are given to `fstab` for the mount process as well.
+
+Example:
+
+```yaml
+btrfs_mounts:
+  - path: "/home"
+    subvol: "@home"
+    uuid: "3204f33f-5fa7-4c11-bdd8-979c539fce91"
+    opts: "defaults,ssd,noatime,compress=zstd:3,space_cache=v2"
+
+  - path: "/srv/media"
+    subvol: "@media"
+    uuid: "2256bd23-7751-486a-bfc4-b216a6b0c4f4"
+    opts: "defaults,noatime,compress=zstd:3,space_cache=v2"
+```
+
+---
+
+`should_mount_external_hdd` can be toggled to automatically mount a USB-connected HDD on boot, or not.

roles/filesystem/defaults/main.yaml

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+---
+should_mount_external_hdd: true
+should_reboot_machine: false
+
+btrfs_mounts:
+  - path: "/"
+    subvol: "@rootfs"
+    uuid: "3204f33f-5fa7-4c11-bdd8-979c539fce91"
+    opts: "defaults,ssd,noatime,compress=zstd:3,space_cache=v2"
+  - path: "/home"
+    subvol: "@home"
+    uuid: "3204f33f-5fa7-4c11-bdd8-979c539fce91"
+    opts: "defaults,ssd,noatime,compress=zstd:3,space_cache=v2"
+
+  - path: "/srv/media"
+    subvol: "@media"
+    uuid: "2256bd23-7751-486a-bfc4-b216a6b0c4f4"
+    opts: "defaults,noatime,compress=zstd:3,space_cache=v2"
+  - path: "/srv/files"
+    subvol: "@files"
+    uuid: "2256bd23-7751-486a-bfc4-b216a6b0c4f4"
+    opts: "defaults,noatime,compress=zstd:3,space_cache=v2"
+  - path: "/srv/documents"
+    subvol: "@documents"
+    uuid: "2256bd23-7751-486a-bfc4-b216a6b0c4f4"
+    opts: "defaults,noatime,compress=zstd:3,space_cache=v2"
+  - path: "/srv/wolf"
+    subvol: "@wolf"
+    uuid: "2256bd23-7751-486a-bfc4-b216a6b0c4f4"
+    opts: "defaults,noatime,compress=zstd:1,space_cache=v2"

roles/filesystem/handlers/main.yaml

@@ -0,0 +1,7 @@
+---
+
+- name: Reboot machine
+  ansible.builtin.reboot:
+    connect_timeout: 600
+    post_reboot_delay: 10
+  when: "should_reboot_machine"

roles/filesystem/tasks/main.yaml

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+---
+- name: Ensure btrfs ROOT layout
+  community.general.btrfs_subvolume:
+    name: "/{{ item.subvol }}"
+    # filesystem_device: /dev/sdb1
+    # fileystem_label: btrfs-root # only 1 of the 3 required
+    filesystem_uuid: "{{ item.uuid }}"
+  loop: "{{ btrfs_mounts }}"
+  become: true
+
+- name: Ensure fstab contains btrfs mount entries
+  ansible.posix.mount:
+    path: "{{ item.path }}"
+    src: "UUID={{ item.uuid }}"
+    fstype: btrfs
+    opts: "{{ item.opts }},subvol={{ item.subvol }}"
+    state: present
+  loop: "{{ btrfs_mounts }}"
+  become: true
+  notify: Reboot machine
+
+- name: Ensure external HDD is mounted
+  ansible.posix.mount:
+    path: /mnt/ext
+    src: "UUID=01b221f2-83a5-49e4-bdef-ee9ee9ac5310"
+    fstype: ext4
+    opts: "noatime"
+    state: present
+  become: true
+  when: "should_mount_external_hdd"

roles/filesystem/vars/main.yaml

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+---
+# vars file for btrfs

site.yaml

@@ -20,6 +20,11 @@
 - name: Prepare incus server host
   hosts: host_system
   tasks:
+    - name: Prepare host filesystems
+      ansible.builtin.import_role:
+        name: filesystem
+      tags: filesystem
+
     - name: Prepare system
       ansible.builtin.import_role:
         name: system