Move redfish-virtual-media to the back of supported_boot_interfaces

Support for virtual media is still limited, we don't want it to become
the default (yet).

Change-Id: I5cd1c5acbc27f554104be13a71865748f801dbd7

ironic/drivers/redfish.py

@@ -53,5 +53,7 @@ class RedfishHardware(generic.GenericHardware):
     @property
     def supported_boot_interfaces(self):
         """List of supported boot interfaces."""
-        return [redfish_boot.RedfishVirtualMediaBoot,
-                ipxe.iPXEBoot, pxe.PXEBoot]
+        # NOTE(dtantsur): virtual media goes last because of limited hardware
+        # vendors support.
+        return [ipxe.iPXEBoot, pxe.PXEBoot,
+                redfish_boot.RedfishVirtualMediaBoot]

releasenotes/notes/redfish-priorities-adf4b7bfbee0ca25.yaml

@@ -0,0 +1,13 @@
+---
+upgrade:
+  - |
+    The ``redfish-virtual-media`` boot interface is now the last in the list of
+    priorities from the ``redfish`` hardware type. This means that new nodes
+    will be created with ``ipxe`` or ``pxe`` boot if they are enabled. The
+    reason for this change is limited support for pure Redfish virtual media
+    from hardware vendors.
+
+    To use virtual media with Redfish, please provide an explicit
+    ``boot_interface`` parameter when creating nodes. If you enable only the
+    ``redfish`` hardware type, you can also set the ``default_boot_interface``
+    configuration option to ``redfish-virtual-media``.