Enable the ramdisk deploy by default

It proved useful (supported by Metal3, used in OpenShift) and does not
require any conductor-level configuration.

Change-Id: I57e59ac21e3327b9ad2f1d1436e184b48999006b

doc/source/admin/ramdisk-boot.rst

@@ -11,8 +11,9 @@ It is suported by ``pxe``, ``ipxe``, ``redfish-virtual-media`` and
 Configuration
 -------------
 
-Ramdisk/ISO boot requires using the ``ramdisk`` deploy interface. As with most
-non-default interfaces, it must be enabled and set for a node to be utilized:
+Ramdisk/ISO boot requires using the ``ramdisk`` deploy interface. It is enabled
+by default starting with the Zed release cycle. On an earlier release, it must
+be enabled explicitly:
 
 .. code-block:: ini
 

ironic/conf/default.py

@@ -111,7 +111,7 @@ driver_opts = [
     cfg.StrOpt('default_console_interface',
                help=_DEFAULT_IFACE_HELP.format('console')),
     cfg.ListOpt('enabled_deploy_interfaces',
-                default=['direct'],
+                default=['direct', 'ramdisk'],
                 help=_ENABLED_IFACE_HELP.format('deploy')),
     cfg.StrOpt('default_deploy_interface',
                help=_DEFAULT_IFACE_HELP.format('deploy')),

ironic/tests/base.py

@@ -159,7 +159,7 @@ class TestCase(oslo_test_base.BaseTestCase):
                 values = ['fake']
 
             if iface == 'deploy':
-                values.extend(['direct', 'anaconda'])
+                values.extend(['direct', 'ramdisk', 'anaconda'])
             elif iface == 'boot':
                 values.append('pxe')
             elif iface == 'storage':

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

@@ -47,8 +47,6 @@ class RamdiskDeployTestCase(db_base.DbTestCase):
         self.config(tftp_root=self.temp_dir, group='pxe')
         self.temp_dir = tempfile.mkdtemp()
         self.config(images_path=self.temp_dir, group='pxe')
-        self.config(enabled_deploy_interfaces=['ramdisk'])
-        self.config(enabled_boot_interfaces=['pxe'])
         for iface in drivers_base.ALL_INTERFACES:
             impl = 'fake'
             if iface == 'network':

releasenotes/notes/ramdisk-deploy-384a38c3c96059dd.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    The ``ramdisk`` deploy interface is now enabled by default. When the
+    default ``direct`` deploy is also enabled, the ``ramdisk`` deploy must be
+    explicitly requested on the node level.