Allow to define only overrides for mounts

In case some mounts are present for systems out of the box, it
might be still important to apply overrides for it, like custom options.

For that we add new `mount_overrides_only` key to `systemd_mounts`
mapping, alike to how it is already done for networkd and serviced.

Change-Id: Ib421508cd76147cb314a579a2b4e918604cf3652
Signed-off-by: Dmitriy Rabotyagov <dmitriy.rabotyagov@cleura.com>

defaults/main.yml

@@ -70,5 +70,11 @@ systemd_default_mount_options: "defaults"
 #   - what: gluster-server:gluster-volume-name
 #     where: /mnt/shared_storage
 #     type: glusterfs
-
+#   - what: dev-hugepages
+#     mount_overrides_only: true
+#     type: hugetlbfs
+#     escape_name: false
+#     config_overrides:
+#       Mount:
+#         Options: pagesize=2MB
 systemd_mounts: []

releasenotes/notes/mount_overrides_only-89328df74372529e.yaml

@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    For ``systemd_mount`` role added ``mount_overrides_only`` to
+    ``systemd_mounts`` mapping. This key is desinged to apply systemd
+    overrides for already existing mounts, which are not managed by
+    the role directly.

tasks/systemd_mounts.yml

@@ -66,9 +66,35 @@
     config_type: "ini"
   when:
     - item.state | default('unknown') != 'absent'
+    - (item.mount_overrides_only is not defined) or (item.mount_overrides_only is defined and not item.mount_overrides_only)
   tags:
     - systemd-mount
 
+- name: Provision mount overrides file
+  when:
+    - item.mount_overrides_only is defined
+    - item.mount_overrides_only | bool
+    - item.config_overrides | length > 0
+  tags:
+    - systemd-mount
+  block:
+    - name: Create overrides folder for mount
+      ansible.builtin.file:
+        path: "/etc/systemd/system/{{ mount_service_name }}.d"
+        owner: "root"
+        group: "root"
+        mode: "0755"
+        state: directory
+
+    - name: Create overrides file
+      openstack.config_template.config_template:
+        dest: "/etc/systemd/system/{{ mount_service_name }}.d/overrides.conf"
+        owner: "root"
+        group: "root"
+        mode: "0644"
+        config_overrides: "{{ item.config_overrides | default({}) }}"
+        config_type: "ini"
+
 - name: Load or Unload mount(s)
   ansible.builtin.systemd:
     daemon_reload: true

tests/prepare.yml

@@ -21,3 +21,11 @@
 
 - name: Importing test-create-ext4-dev
   ansible.builtin.import_playbook: test-create-ext4-dev.yml
+
+- name: Unmask dev-hugepages mount
+  hosts: mount_hosts
+  tasks:
+    - name: Unmask hugepages
+      ansible.builtin.systemd:
+        name: dev-hugepages.mount
+        masked: false

tests/test.yml

@@ -51,3 +51,11 @@
               ? network.target
               ? network-online.target
             Wants: network-online.target
+
+      - what: dev-hugepages
+        mount_overrides_only: true
+        type: hugetlbfs
+        escape_name: false
+        config_overrides:
+          Mount:
+            Options: pagesize=2MB

tests/verify.yml

@@ -17,7 +17,7 @@
   hosts: mount_hosts
   tasks:
     - name: Ensure mount are mounted
-      command: grep -w '{{ item }}' /proc/mounts
+      ansible.builtin.command: grep -w '{{ item }}' /proc/mounts
       changed_when: false
       with_items:
         - /var/lib/sparse-file
@@ -29,3 +29,13 @@
     #   shell: swapon | grep -w '/var/lib/test-swap.img'
     #   tags:
     #     - skip_ansible_lint
+
+    - name: Fetch override files for hugepages
+      ansible.builtin.slurp:
+        src: /etc/systemd/system/dev-hugepages.mount.d/overrides.conf
+      register: hugepages_overrides
+
+    - name: Verify hugepages overrides
+      ansible.builtin.assert:
+        that:
+          - "'pagesize=2MB' in hugepages_overrides.content | b64decode"