Accept a fixed partition size for reset partition in autoinstall.yaml

doc/reference/autoinstall-reference.rst

@@ -423,6 +423,41 @@ Example with no size scaling and a passphrase:
         sizing-policy: all
         password: LUKS_PASSPHRASE
 
+Reset Partition
+^^^^^^^^^^^^^^^
+
+``reset-partition`` is used for creating a Reset Partition, which is a FAT32 file system containing the entire content of the installer image, so that the user can start the installer from GRUB or EFI without using the installation media. This option is useful for OEM system provisioning.
+
+By default, the size of a Reset Partition is roughly 1.1x the used file system size of the installation media.
+
+An example to enable Reset Partition:
+
+.. code-block:: yaml
+
+    storage:
+      layout:
+        name: direct
+        reset-partition: true
+
+The size of the reset partition can also be fixed to a specified size.  This is an example to fix Reset Partition to 12 GiB:
+
+.. code-block:: yaml
+
+    storage:
+      layout:
+        name: direct
+        reset-partition: 12G
+
+The installer can also install Reset Partition without installing the system.  To do this, set ``reset-partition-only`` to ``true``:
+
+.. code-block:: yaml
+
+    storage:
+      layout:
+        name: direct
+        reset-partition: true
+        reset-partition-only: true
+
 Action-based configuration
 ^^^^^^^^^^^^^^^^^^^^^^^^^^
 

subiquity/common/types.py

@@ -531,6 +531,7 @@ class GuidedChoiceV2:
 
     sizing_policy: Optional[SizingPolicy] = SizingPolicy.SCALED
     reset_partition: bool = False
+    reset_partition_size: Optional[int] = None
 
 
 @attr.s(auto_attribs=True)

subiquity/server/controllers/filesystem.py

@@ -29,6 +29,7 @@
 from curtin import swap
 from curtin.commands.extract import AbstractSourceHandler
 from curtin.storage_config import ptable_part_type_to_flag
+from curtin.util import human2bytes
 
 from subiquity.common.apidef import API
 from subiquity.common.errorreport import ErrorReportKind
@@ -707,7 +708,10 @@ async def guided(
             raise Exception("failed to locate gap after adding boot")
 
         if choice.reset_partition:
-            if self.app.opts.dry_run:
+            if choice.reset_partition_size is not None:
+                part_align = disk.alignment_data().part_align
+                reset_size = align_up(choice.reset_partition_size, part_align)
+            elif self.app.opts.dry_run:
                 reset_size = DRY_RUN_RESET_SIZE
             else:
                 cp = await arun_command(["du", "-sb", "/cdrom"])
@@ -1410,6 +1414,20 @@ async def run_autoinstall_guided(self, layout):
                 disk_id=gap.device.id, gap=gap, allowed=[]
             )
 
+        reset_partition = False
+        reset_partition_size = None
+        rp_input = layout.get("reset-partition", None)
+        if rp_input:
+            reset_partition = True
+            if isinstance(rp_input, (str, int)):
+                reset_partition_size = int(human2bytes(rp_input))
+                log.info(
+                    "autoinstall: will install reset partition "
+                    f"of size {reset_partition_size}"
+                )
+            else:
+                log.info("autoinstall: will install reset partition")
+
         log.info(
             f"autoinstall: running guided {capability} install in "
             f"mode {mode} using {target}"
@@ -1421,7 +1439,8 @@ async def run_autoinstall_guided(self, layout):
                 password=password,
                 recovery_key=guided_recovery_key,
                 sizing_policy=sizing_policy,
-                reset_partition=layout.get("reset-partition", False),
+                reset_partition=reset_partition,
+                reset_partition_size=reset_partition_size,
             ),
             reset_partition_only=layout.get("reset-partition-only", False),
         )

subiquity/server/controllers/tests/test_filesystem.py

@@ -459,6 +459,26 @@ async def test_guided_reset_partition(self):
         self.assertEqual(DRY_RUN_RESET_SIZE, d1p2.size)
         self.assertEqual("/", d1p3.mount)
 
+    async def test_fixed_reset_partition(self):
+        await self._guided_setup(Bootloader.UEFI, "gpt")
+        target = GuidedStorageTargetReformat(
+            disk_id=self.d1.id, allowed=default_capabilities
+        )
+        fixed_reset_size = 12 << 30
+        await self.controller.guided(
+            GuidedChoiceV2(
+                target=target,
+                capability=GuidedCapability.DIRECT,
+                reset_partition=True,
+                reset_partition_size=fixed_reset_size,
+            )
+        )
+        [d1p1, d1p2, d1p3] = self.d1.partitions()
+        self.assertEqual("/boot/efi", d1p1.mount)
+        self.assertIsNone(d1p2.mount)
+        self.assertEqual(fixed_reset_size, d1p2.size)
+        self.assertEqual("/", d1p3.mount)
+
     async def test_guided_reset_partition_only(self):
         await self._guided_setup(Bootloader.UEFI, "gpt")
         target = GuidedStorageTargetReformat(