Fix grub issue for all redhat based OSes with version 9+

coriolis/osmorphing/redhat.py

@@ -69,14 +69,23 @@ class BaseRedHatMorphingTools(base.BaseLinuxOSMorphingTools):
         return "grub2-mkconfig -o %s" % location
 
     def _get_grub2_cfg_location(self):
+        """Get GRUB2 config location for Red Hat-based distros.
+
+        On RHEL 9.4+ and related distros (Rocky, Alma, etc.), the EFI grub.cfg
+        is a wrapper that loads from /boot/grub2/grub.cfg. grub2-mkconfig
+        refuses to overwrite the wrapper and requires output to
+        /boot/grub2/grub.cfg. Prefer the BIOS path when it exists.
+        """
         self._exec_cmd_chroot("mount /boot || true")
         self._exec_cmd_chroot("mount /boot/efi || true")
         uefi_cfg = os.path.join(self.UEFI_GRUB_LOCATION, "grub.cfg")
         bios_cfg = os.path.join(self.BIOS_GRUB_LOCATION, "grub.cfg")
-        if self._test_path_chroot(uefi_cfg):
-            return uefi_cfg
+        # Prefer /boot/grub2/grub.cfg - on RHEL 9.4+ UEFI, the EFI file is a
+        # wrapper and grub2-mkconfig must write to /boot/grub2/grub.cfg
         if self._test_path_chroot(bios_cfg):
             return bios_cfg
+        if self._test_path_chroot(uefi_cfg):
+            return uefi_cfg
         raise Exception(
             "could not determine grub location."
             " boot partition not mounted?")

coriolis/tests/osmorphing/test_redhat.py

@@ -70,35 +70,37 @@ class BaseRedHatMorphingToolsTestCase(test_base.CoriolisBaseTestCase):
 
     @mock.patch.object(base.BaseLinuxOSMorphingTools, '_exec_cmd_chroot')
     @mock.patch.object(base.BaseLinuxOSMorphingTools, '_test_path_chroot')
-    def test__get_grub2_cfg_location_uefi(self, mock_test_path_chroot,
+    def test__get_grub2_cfg_location_bios(self, mock_test_path_chroot,
                                           mock_exec_cmd_chroot):
         mock_test_path_chroot.return_value = True
 
         result = self.morphing_tools._get_grub2_cfg_location()
 
-        self.assertEqual(result, '/boot/efi/EFI/redhat/grub.cfg')
+        self.assertEqual(result, '/boot/grub2/grub.cfg')
         mock_exec_cmd_chroot.assert_has_calls([
             mock.call("mount /boot || true"),
             mock.call("mount /boot/efi || true")
         ])
         mock_test_path_chroot.assert_called_once_with(
-            '/boot/efi/EFI/redhat/grub.cfg')
+            '/boot/grub2/grub.cfg')
 
     @mock.patch.object(base.BaseLinuxOSMorphingTools, '_exec_cmd_chroot')
     @mock.patch.object(base.BaseLinuxOSMorphingTools, '_test_path_chroot')
-    def test__get_grub2_cfg_location_bios(self, mock_test_path_chroot,
+    def test__get_grub2_cfg_location_uefi(self, mock_test_path_chroot,
                                           mock_exec_cmd_chroot):
         mock_test_path_chroot.side_effect = [False, True]
 
         result = self.morphing_tools._get_grub2_cfg_location()
 
-        mock_test_path_chroot.assert_called_with('/boot/grub2/grub.cfg')
+        self.assertEqual(result, '/boot/efi/EFI/redhat/grub.cfg')
         mock_exec_cmd_chroot.assert_has_calls([
             mock.call("mount /boot || true"),
             mock.call("mount /boot/efi || true")
         ])
-
-        self.assertEqual(result, '/boot/grub2/grub.cfg')
+        mock_test_path_chroot.assert_has_calls([
+            mock.call('/boot/grub2/grub.cfg'),
+            mock.call('/boot/efi/EFI/redhat/grub.cfg')
+        ])
 
     @mock.patch.object(base.BaseLinuxOSMorphingTools, '_exec_cmd_chroot')
     @mock.patch.object(base.BaseLinuxOSMorphingTools, '_test_path_chroot')
@@ -117,8 +119,8 @@ class BaseRedHatMorphingToolsTestCase(test_base.CoriolisBaseTestCase):
             mock.call("mount /boot/efi || true")
         ])
         mock_test_path_chroot.assert_has_calls([
-            mock.call('/boot/efi/EFI/redhat/grub.cfg'),
-            mock.call('/boot/grub2/grub.cfg')
+            mock.call('/boot/grub2/grub.cfg'),
+            mock.call('/boot/efi/EFI/redhat/grub.cfg')
         ])
 
     @mock.patch.object(base.BaseLinuxOSMorphingTools, '_exec_cmd_chroot')