fix: configure udev rule to make zram swap reboot persistent

tasks/configure_swap.yml

@@ -15,7 +15,6 @@
   when: ansible_os_family == "Debian"
 
 # RHEL part is based on https://www.techrepublic.com/article/how-to-enable-zram-rocky-linux/
-#   Note: all that udev stuff from that guide doesn't work. We'll use CLI commands.
 # More docu on zram at https://www.kernel.org/doc/html/latest/admin-guide/blockdev/zram.html
 - name: configure zram based swap (RedHat)
   block:
@@ -41,6 +40,12 @@
         create: true
         line: "options zram num_devices=1"
         mode: "0644"
+    - name: configure udev to initialise zram device on bootup
+      ansible.builtin.lineinfile:
+        path: "/etc/udev/rules.d/99-zram.rules"
+        create: true
+        line: "KERNEL==\"zram0\", ATTR{disksize}=\"{{ ( ansible_facts.memtotal_mb / 2 ) | round | int }}M\",TAG+=\"systemd\""
+        mode: "0644"
     - name: find out if zram Kernel module has been loaded already
       ansible.builtin.command: "lsmod"
       register: kernel_modules