Enable Ironic iPXE support by default

Ironic has changed the default PXE to be iPXE (as opposed to plain
PXE) in Yoga. Kolla Ansible supports either one or the other and
we tend to stick to upstream defaults so this change enables
iPXE instead of plain PXE - by default - the users are allowed
to change back and they need to take one other action so it is
good to remind them via upgrade notes either way.

Change-Id: If14ec83670d2212906c6e22c7013c475f3c4748a

ansible/group_vars/all.yml

@@ -651,7 +651,7 @@ enable_horizon_watcher: "{{ enable_watcher | bool }}"
 enable_horizon_zun: "{{ enable_zun | bool }}"
 enable_influxdb: "{{ enable_monasca | bool or (enable_cloudkitty | bool and cloudkitty_storage_backend == 'influxdb') }}"
 enable_ironic: "no"
-enable_ironic_ipxe: "no"
+enable_ironic_ipxe: "yes"
 enable_ironic_neutron_agent: "{{ enable_neutron | bool and enable_ironic | bool }}"
 enable_ironic_pxe_uefi: "no"
 enable_iscsid: "{{ enable_cinder | bool and enable_cinder_backend_iscsi | bool }}"

doc/source/reference/bare-metal/ironic-guide.rst

@@ -66,20 +66,8 @@ You may optionally pass extra kernel parameters to the inspection kernel using:
 
 in ``/etc/kolla/globals.yml``.
 
-Enable iPXE booting (optional)
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-You can optionally enable booting via iPXE by setting ``enable_ironic_ipxe`` to
-true in ``/etc/kolla/globals.yml``:
-
-.. code-block:: yaml
-
-   enable_ironic_ipxe: "yes"
-
-When iPXE booting is enabled, the ``ironic_ipxe`` container is used to serve
-the iPXE boot images as described below. Regardless of the setting above, the
-same container is used to support the ``direct`` deploy interface.
-
+Configure iPXE HTTP server port (optional)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 The port used for the iPXE webserver is controlled via ``ironic_ipxe_port`` in
 ``/etc/kolla/globals.yml``:
 
@@ -87,25 +75,31 @@ The port used for the iPXE webserver is controlled via ``ironic_ipxe_port`` in
 
     ironic_ipxe_port: "8089"
 
-The following changes will occur if iPXE booting is enabled:
+Revert to plain PXE (not recommended)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Starting with Yoga, Ironic has changed the default PXE from plain PXE to iPXE.
+Kolla Ansible follows this upstream decision but allows users to revert to
+plain PXE. Please note Kolla Ansible does not support plain PXE and iPXE at the
+same time - the user must choose one.
 
-- Ironic will be configured with the ``ipxe_enabled`` configuration option set
-  to true
-- The inspection ramdisk and kernel will be loaded via iPXE
-- The DHCP servers will be configured to chainload iPXE from an existing PXE
-  environment. You may also boot directly to iPXE by some other means e.g by
-  burning it to the option rom of your ethernet card.
+If you have to revert to plain iPXE, set:
 
-Note that due to a limitation in Kolla Ansible, PXE and iPXE cannot be used
-together in a single deployment.
+.. code-block:: yaml
 
-In order to enable the iPXE driver in Ironic, set the ``[DEFAULT]
-enabled_boot_interfaces`` option in ``/etc/kolla/config/ironic.conf``:
+   enable_ironic_ipxe: "no"
+
+And also remove ``ipxe`` from the ``enabled_boot_interfaces`` in
+``/etc/kolla/config/ironic.conf``, leaving only ``pxe`` (and possibly other
+alternatives) around:
 
 .. code-block:: yaml
 
    [DEFAULT]
-   enabled_boot_interfaces = ipxe
+   enabled_boot_interfaces = pxe
+
+When iPXE booting is enabled, the ``ironic_ipxe`` container is used to serve
+the iPXE boot images as described below. Regardless of that setting, the
+same container is used to support the ``direct`` deploy interface.
 
 Attach ironic to external keystone (optional)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

etc/kolla/globals.yml

@@ -345,7 +345,7 @@
 #enable_horizon_zun: "{{ enable_zun | bool }}"
 #enable_influxdb: "{{ enable_monasca | bool or (enable_cloudkitty | bool and cloudkitty_storage_backend == 'influxdb') }}"
 #enable_ironic: "no"
-#enable_ironic_ipxe: "no"
+#enable_ironic_ipxe: "yes"
 #enable_ironic_neutron_agent: "{{ enable_neutron | bool and enable_ironic | bool }}"
 #enable_ironic_pxe_uefi: "no"
 #enable_iscsid: "{{ enable_cinder | bool and enable_cinder_backend_iscsi | bool }}"

releasenotes/notes/ironic-default-ipxe-1e9bb7a3f4994d84.yaml

@@ -0,0 +1,9 @@
+---
+upgrade:
+  - |
+    Starting with Yoga, Ironic has changed the default PXE from plain PXE to
+    iPXE.
+    Kolla Ansible follows this upstream decision but allows users to revert to
+    plain PXE. Please note Kolla Ansible does not support plain PXE and iPXE at
+    the same time - the user must choose one. For details, please refer to
+    Kolla Ansible's documentation.