Introduce default_boot_option configuration option

This is the first step to changing the default boot option from netboot to local.
The new configuration allows setting the default boot option globally.

A warning is issued if no explicit value is provided for this configuration.

Change-Id: I3bd4a165fa2ec1105f34bf5a2150da99136ba4a6
Partial-Bug: #1619339

devstack/lib/ironic

@@ -770,6 +770,9 @@ function configure_ironic_conductor {
     if [[ -n "$IRONIC_ENABLED_NETWORK_INTERFACES" ]]; then
         iniset $IRONIC_CONF_FILE DEFAULT enabled_network_interfaces $IRONIC_ENABLED_NETWORK_INTERFACES
     fi
+
+    # TODO(dtantsur): change this when we change the default value.
+    iniset $IRONIC_CONF_FILE deploy default_boot_option netboot
 }
 
 # create_ironic_cache_dir() - Part of the init_ironic() process

etc/ironic/ironic.conf.sample

@@ -996,6 +996,14 @@
 # to True. (boolean value)
 #power_off_after_deploy_failure = true
 
+# Default boot option to use when no boot option is requested
+# in node's driver_info. Currently the default is "netboot",
+# but it will be changed to "local" in the future. It is
+# recommended to set an explicit value for this option.
+# (string value)
+# Allowed values: netboot, local
+#default_boot_option = <None>
+
 
 [dhcp]
 

ironic/conf/deploy.py

@@ -68,6 +68,13 @@ opts = [
                 default=True,
                 help=_('Whether to power off a node after deploy failure. '
                        'Defaults to True.')),
+    cfg.StrOpt('default_boot_option',
+               choices=['netboot', 'local'],
+               help=_('Default boot option to use when no boot option is '
+                      'requested in node\'s driver_info. Currently the '
+                      'default is "netboot", but it will be changed to '
+                      '"local" in the future. It is recommended to set '
+                      'an explicit value for this option.')),
 ]
 
 

ironic/drivers/modules/deploy_utils.py

@@ -79,7 +79,17 @@ def warn_about_unsafe_shred_parameters():
                         'Secure Erase. This is a possible SECURITY ISSUE!'))
 
 
+def warn_about_missing_default_boot_option():
+    if not CONF.deploy.default_boot_option:
+        LOG.warning(_LW('The default value of default_boot_option '
+                        'configuration will change eventually from '
+                        '"netboot" to "local". It is recommended to set '
+                        'an explicit value for it during the transition '
+                        'period'))
+
+
 warn_about_unsafe_shred_parameters()
+warn_about_missing_default_boot_option()
 
 # All functions are called from deploy() directly or indirectly.
 # They are split for stub-out.
@@ -311,7 +321,7 @@ def deploy_partition_image(
         address, port, iqn, lun, image_path,
         root_mb, swap_mb, ephemeral_mb, ephemeral_format, node_uuid,
         preserve_ephemeral=False, configdrive=None,
-        boot_option="netboot", boot_mode="bios", disk_label=None):
+        boot_option=None, boot_mode="bios", disk_label=None):
     """All-in-one function to deploy a partition image to a node.
 
     :param address: The iSCSI IP address.
@@ -345,6 +355,7 @@ def deploy_partition_image(
         NOTE: If key exists but value is None, it means partition doesn't
               exist.
     """
+    boot_option = boot_option or get_default_boot_option()
     image_mb = disk_utils.get_image_mb(image_path)
     if image_mb > root_mb:
         msg = (_('Root partition is too small for requested image. Image '
@@ -907,6 +918,11 @@ def validate_image_properties(ctx, deploy_info, properties):
             "%(properties)s") % {'image': image_href, 'properties': props})
 
 
+def get_default_boot_option():
+    """Gets the default boot option."""
+    return CONF.deploy.default_boot_option or 'netboot'
+
+
 def get_boot_option(node):
     """Gets the boot option.
 
@@ -917,7 +933,7 @@ def get_boot_option(node):
         'netboot'.
     """
     capabilities = parse_instance_info_capabilities(node)
-    return capabilities.get('boot_option', 'netboot').lower()
+    return capabilities.get('boot_option', get_default_boot_option()).lower()
 
 
 # TODO(vdrok): This method is left here for backwards compatibility with out of

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

@@ -1396,6 +1396,19 @@ class OtherFunctionTestCase(db_base.DbTestCase):
         result = utils.get_boot_option(self.node)
         self.assertEqual("netboot", result)
 
+    def test_get_boot_option_overriden_default_value(self):
+        cfg.CONF.set_override('default_boot_option', 'local', 'deploy')
+        self.node.instance_info = {}
+        result = utils.get_boot_option(self.node)
+        self.assertEqual("local", result)
+
+    def test_get_boot_option_instance_info_priority(self):
+        cfg.CONF.set_override('default_boot_option', 'local', 'deploy')
+        self.node.instance_info = {'capabilities':
+                                   '{"boot_option": "netboot"}'}
+        result = utils.get_boot_option(self.node)
+        self.assertEqual("netboot", result)
+
     @mock.patch.object(image_cache, 'clean_up_caches', autospec=True)
     def test_fetch_images(self, mock_clean_up_caches):
 

releasenotes/notes/default_boot_option-f22c01f976bc2de7.yaml

@@ -0,0 +1,8 @@
+---
+features:
+  - Adds new option "[deploy]/default_boot_option" for setting the default
+    boot option when no explicit boot option is requested via capabilities.
+upgrade:
+  - We are going to change the default value of "[deploy]/default_boot_option"
+    from "netboot" to "local" eventually. To avoid disruptions, it is
+    recommended to an explicit value to this option.