Guardrails to ensure we dont run target LV out of space; minor tweaks

tasks/capture_lv_device_details.yml

@@ -109,7 +109,7 @@
     - name: Assert if we need to shrink the logical volume to gain PE
       ansible.builtin.assert:
         that: (bigboot_lv_pe_size_in_mb[:-3] | int) >= (bigboot_expansion_diff_mb[:-3] | int)
-        fail_msg: Not enough PE to expand /boot.
+        fail_msg: Not enough PE to expand /boot. Will need to shrink target LV.
 
   rescue:
     - name: Set flag for Shrink_LV execution

tasks/check_space_fallback.yml

@@ -7,7 +7,7 @@
   ansible.builtin.assert:
     that: bigboot_size_target_fallback | int >= bigboot_size_min | human_to_bytes
     fail_msg:
-      "{{ bigboot_size_target_fallback | int | human_readable(unit='M') }} is less than the minimum of {{ bigboot_size_min }}"
+      "{{ bigboot_size_target_fallback | int | human_readable(unit='M') }} is less than the minimum required size of {{ bigboot_size_min }}."
 
 - name: Verify available space and re-check if needed
   block:
@@ -16,6 +16,16 @@
         that: bigboot_lv_info['size_available'] > bigboot_expansion_diff | int
         fail_msg: There is not enough free space available to shrink the filesystem
 
+    - name: Debug bigboot_lv_info
+      ansible.builtin.debug:
+        msg: "{{ bigboot_lv_info['size_available'] }} -> {{ bigboot_expansion_diff }} -> {{ bigboot_lv_size_min | human_to_bytes }}"
+
+    - name: Assert that there will be enough space left over on the target LV
+      ansible.builtin.assert:
+        that: (bigboot_lv_info['size_available'] - bigboot_expansion_diff | int) >= bigboot_lv_size_min | human_to_bytes
+        success_msg: "There will be enough space left over with a boot size of {{ bigboot_size_target_fallback | int | human_readable(unit='G') }}."
+        fail_msg: "There will NOT be enough space left over with a boot size of {{ bigboot_size_target_fallback | int | human_readable(unit='G') }}. Aborting Bigboot execution."
+
   rescue:
     - name: "Decrement size target by {{ bigboot_size_decrement }}"
       ansible.builtin.set_fact:

vars/bigboot_vars.yml

@@ -5,6 +5,8 @@ bigboot_size_target: 2G
 bigboot_size_min: 1G
 bigboot_size_decrement: 250M
 
+bigboot_lv_size_min: 1G
+
 # Filename of disabled services log:
 bigboot_disabled_services_log: /var/IPE/IPU/el7to8/bigboot_disabled_services.log