raid-array: Create udev rules to auto re-add disks

This udev rule will automatically re-add disks to the RAID array when
they are connected.  `mdadm --udev-rules` is supposed to be able to
generate such a rule based on the `POLICY` definitions in
`/etc/mdadm.conf`, but I was not able to get that to work; it always
printed an empty rule file, no matter what I put in `mdadm.conf`.

raid-array.yml

@@ -29,3 +29,22 @@
     tags:
     - mdadm
     - mdadm-create
+  - name: ensure raid auto re-add udev rule exists
+    copy:
+      content: >+
+        ENV{ID_FS_LABEL}=="{{ md_name }}",
+        ENV{ID_FS_TYPE}=="linux_raid_member",
+        ENV{ID_FS_USAGE}=="raid",
+        RUN+="/usr/sbin/mdadm --re-add /dev/disk/by-id/md-name-{{ md_name }} $devnode"
+      dest: /etc/udev/rules.d/80-{{ md_name }}.rules
+      mode: u=rw,go=r
+      owner: root
+      group: root
+    notify:
+    - reload udev
+    tags:
+    - udev
+  handlers:
+  - name: reload udev
+    command:
+      udevadm control --reload