Merge "Extend root device hints to support device name"

doc/source/deploy/install-guide.rst

@@ -1802,16 +1802,9 @@ The node should be in MANAGEABLE state before inspection is initiated.
 Specifying the disk for deployment
 ==================================
 
-Starting with the Kilo release, Bare Metal service supports passing hints to the
-deploy ramdisk about which disk it should pick for the deployment. In
-Linux when a server has more than one SATA, SCSI or IDE disk controller,
-the order in which their corresponding device nodes are added is arbitrary
-[`link`_], resulting in devices like ``/dev/sda`` and ``/dev/sdb`` to
-switch around between reboots. Therefore, to guarantee that a specific
-disk is always chosen for the deployment, Bare Metal service introduced
-root device hints.
-
-The list of support hints is:
+Starting with the Kilo release, Bare Metal service supports passing
+hints to the deploy ramdisk about which disk it should pick for the
+deployment. The list of support hints is:
 
 * model (STRING): device identifier
 * vendor (STRING): device vendor
@@ -1828,6 +1821,17 @@ The list of support hints is:
 * wwn (STRING): unique storage identifier
 * wwn_with_extension (STRING): unique storage identifier with the vendor extension appended
 * wwn_vendor_extension (STRING): unique vendor storage identifier
+* name (STRING): the device name, e.g /dev/md0
+
+
+  .. warning::
+     The root device hint name should only be used for devices with
+     constant names (e.g RAID volumes). For SATA, SCSI and IDE disk
+     controllers this hint is not recommended because the order in which
+     the device nodes are added in Linux is arbitrary, resulting in
+     devices like /dev/sda and /dev/sdb `switching around at boot time
+     <https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Storage_Administration_Guide/persistent_naming.html>`_.
+
 
 To associate one or more hints with a node, update the node's properties
 with a ``root_device`` key, for example::
@@ -1843,9 +1847,6 @@ can not be found.
     If multiple hints are specified, a device must satisfy all the hints.
 
 
-.. _`link`: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Storage_Administration_Guide/persistent_naming.html
-
-
 .. _EnableHTTPSinSwift:
 
 Enabling HTTPS in Swift

ironic/drivers/modules/deploy_utils.py

@@ -85,7 +85,8 @@ if CONF.rootwrap_config != '/etc/ironic/rootwrap.conf':
 LOG = logging.getLogger(__name__)
 
 VALID_ROOT_DEVICE_HINTS = set(('size', 'model', 'wwn', 'serial', 'vendor',
-                               'wwn_with_extension', 'wwn_vendor_extension'))
+                               'wwn_with_extension', 'wwn_vendor_extension',
+                               'name'))
 
 SUPPORTED_CAPABILITIES = {
     'boot_option': ('local', 'netboot'),

ironic/tests/unit/drivers/modules/test_deploy_utils.py

@@ -1203,10 +1203,10 @@ class OtherFunctionTestCase(db_base.DbTestCase):
     def test_parse_root_device_hints(self):
         self.node.properties['root_device'] = {
             'wwn': 123456, 'model': 'foo-model', 'size': 123,
-            'serial': 'foo-serial', 'vendor': 'foo-vendor',
+            'serial': 'foo-serial', 'vendor': 'foo-vendor', 'name': '/dev/sda',
             'wwn_with_extension': 123456111, 'wwn_vendor_extension': 111,
         }
-        expected = ('model=foo-model,serial=foo-serial,size=123,'
+        expected = ('model=foo-model,name=/dev/sda,serial=foo-serial,size=123,'
                     'vendor=foo-vendor,wwn=123456,wwn_vendor_extension=111,'
                     'wwn_with_extension=123456111')
         result = utils.parse_root_device_hints(self.node)

releasenotes/notes/name-root-device-hints-a1484ea01e399065.yaml

@@ -0,0 +1,3 @@
+---
+features:
+  - Root device hints extended to support the device name.