Allow bootstrapping virt VM with zvol (#15400)

src/middlewared/middlewared/api/v25_04_0/virt_instance.py

@@ -1,3 +1,4 @@
+import os
 from typing import Annotated, Literal, TypeAlias
 
 from pydantic import Field, model_validator, StringConstraints
@@ -75,8 +76,8 @@ class VirtInstanceEntry(BaseModel):
 @single_argument_args('virt_instance_create')
 class VirtInstanceCreateArgs(BaseModel):
     name: Annotated[NonEmptyString, StringConstraints(max_length=200)]
-    source_type: Literal[None, 'IMAGE', 'ISO'] = 'IMAGE'
     iso_volume: NonEmptyString | None = None
+    source_type: Literal[None, 'IMAGE', 'ZVOL', 'ISO'] = 'IMAGE'
     image: Annotated[NonEmptyString, StringConstraints(max_length=200)] | None = None
     remote: REMOTE_CHOICES = 'LINUX_CONTAINERS'
     instance_type: InstanceType = 'CONTAINER'
@@ -87,6 +88,12 @@ class VirtInstanceCreateArgs(BaseModel):
     memory: MemoryType | None = None
     enable_vnc: bool = False
     vnc_port: int | None = Field(ge=5900, le=65535, default=None)
+    zvol_path: NonEmptyString | None = None
+    '''
+    This is useful when a VM wants to be booted where a ZVOL already has a VM bootstrapped in it and needs
+    to be ported over to virt plugin. Virt will consume this zvol and add it as a DISK device to the instance
+    with boot priority set to 1 so the VM can be booted from it.
+    '''
 
     @model_validator(mode='after')
     def validate_attrs(self):
@@ -95,15 +102,27 @@ def validate_attrs(self):
                 raise ValueError('Source type must be set to "IMAGE" when instance type is CONTAINER')
             if self.enable_vnc:
                 raise ValueError('VNC is not supported for containers and `enable_vnc` should be unset')
+            if self.zvol_path:
+                raise ValueError('Zvol path is only supported for VMs')
         else:
             if self.enable_vnc and self.vnc_port is None:
                 raise ValueError('VNC port must be set when VNC is enabled')
 
             if self.source_type == 'ISO' and self.iso_volume is None:
                 raise ValueError('ISO volume must be set when source type is "ISO"')
 
+            if self.source_type == 'ZVOL':
+                if self.zvol_path is None:
+                    raise ValueError('Zvol path must be set when source type is "ZVOL"')
+                if self.zvol_path.startswith('/dev/zvol/') is False:
+                    raise ValueError('Zvol path must be a valid zvol path')
+                elif not os.path.exists(self.zvol_path):
+                    raise ValueError(f'Zvol path {self.zvol_path} does not exist')
+
         if self.source_type == 'IMAGE' and self.image is None:
             raise ValueError('Image must be set when source type is "IMAGE"')
+        elif self.source_type != 'IMAGE' and self.image:
+            raise ValueError('Image must not be set when source type is not "IMAGE"')
 
         return self
 

src/middlewared/middlewared/plugins/virt/instance.py

@@ -274,21 +274,36 @@ async def do_create(self, job, data):
         verrors = ValidationErrors()
         await self.validate(data, 'virt_instance_create', verrors)
 
-        devices = {}
         data_devices = data['devices'] or []
         iso_volume = data.pop('iso_volume', None)
-        if data['source_type'] == 'ISO':
+        root_device_to_add = None
+        zvol_path = data.pop('zvol_path', None)
+        if data['source_type'] == 'ZVOL':
             data['source_type'] = None
-            data_devices.append({
+            root_device_to_add = {
+                'name': 'ix_virt_zvol_root',
+                'dev_type': 'DISK',
+                'source': zvol_path,
+                'destination': None,
+                'readonly': False,
+                'boot_priority': 1,
+            }
+        elif data['source_type'] == 'ISO':
+            root_device_to_add = {
                 'name': iso_volume,
                 'dev_type': 'DISK',
                 'pool': 'default',
                 'source': iso_volume,
                 'destination': None,
                 'readonly': False,
                 'boot_priority': 1,
-            })
+            }
 
+        if root_device_to_add:
+            data['source_type'] = None
+            data_devices.append(root_device_to_add)
+
+        devices = {}
         for i in data_devices:
             await self.middleware.call(
                 'virt.instance.validate_device', i, 'virt_instance_create', verrors, data['instance_type'],

tests/api2/test_virt_vm.py

@@ -168,6 +168,34 @@ def test_vm_creation_with_iso_volume(vm, iso_volume):
         call('virt.instance.delete', virt_instance_name, job=True)
 
 
+def test_vm_creation_with_zvol(virt_pool, vm, iso_volume):
+    virt_instance_name = 'test-zvol-vm'
+    zvol_name = f'{virt_pool["pool"]}/test_zvol'
+    call('zfs.dataset.create', {
+        'name': zvol_name,
+        'type': 'VOLUME',
+        'properties': {'volsize': '514MiB'}
+    })
+    call('virt.instance.create', {
+        'name': virt_instance_name,
+        'instance_type': 'VM',
+        'source_type': 'ZVOL',
+        'zvol_path': f'/dev/zvol/{zvol_name}',
+    }, job=True)
+
+    try:
+        vm_devices = call('virt.instance.device_list', virt_instance_name)
+        assert any(
+            device['name'] == 'ix_virt_zvol_root'
+            and device['boot_priority'] == 1
+            for device in vm_devices
+        ), vm_devices
+
+    finally:
+        call('virt.instance.delete', virt_instance_name, job=True)
+        call('zfs.dataset.delete', zvol_name)
+
+
 @pytest.mark.parametrize('iso_volume,error_msg', [
     (None, 'Value error, ISO volume must be set when source type is "ISO"'),
     ('test_iso123', 'Invalid ISO volume selected. Please select a valid ISO volume.'),