Mark more configuration options as reloadable

I have only checked the main configuration options and two generic
drivers, leaving everything else untouched. Added are options
that is possible and makes sense to reload.

Change-Id: I74c629bcaf50da7f829f0ec8c526d936b9d40b36

14 files changed, 128 insertions, 1 deletions

diff --git a/ironic/conf/agent.py b/ironic/conf/agent.py
index f0cb7c820..64299742c 100644
--- a/ironic/conf/agent.py
+++ b/ironic/conf/agent.py
@@ -28,6 +28,7 @@ opts = [
                        'ramdisk.')),
     cfg.IntOpt('memory_consumed_by_agent',
                default=0,
+               mutable=True,
                help=_('The memory size in MiB consumed by agent when it is '
                       'booted on a bare metal node. This is used for '
                       'checking if the image can be downloaded and deployed '
@@ -36,6 +37,7 @@ opts = [
                       'the agent ramdisk image.')),
     cfg.BoolOpt('stream_raw_images',
                 default=True,
+                mutable=True,
                 help=_('Whether the agent ramdisk should stream raw images '
                        'directly onto the disk or not. By streaming raw '
                        'images directly onto the disk the agent ramdisk will '
@@ -63,6 +65,7 @@ opts = [
                                          'failure')),
                         ('never', _('never collect logs'))],
                default='on_failure',
+               mutable=True,
                help=_('Whether Ironic should collect the deployment logs on '
                       'deployment failure (on_failure), always or never.')),
     cfg.StrOpt('deploy_logs_storage_backend',
@@ -70,20 +73,24 @@ opts = [
                         ('swift', _('store the logs in Object Storage '
                                     'service'))],
                default='local',
+               mutable=True,
                help=_('The name of the storage backend where the logs '
                       'will be stored.')),
     cfg.StrOpt('deploy_logs_local_path',
                default='/var/log/ironic/deploy',
+               mutable=True,
                help=_('The path to the directory where the logs should be '
                       'stored, used when the deploy_logs_storage_backend '
                       'is configured to "local".')),
     cfg.StrOpt('deploy_logs_swift_container',
                default='ironic_deploy_logs_container',
+               mutable=True,
                help=_('The name of the Swift container to store the logs, '
                       'used when the deploy_logs_storage_backend is '
                       'configured to "swift".')),
     cfg.IntOpt('deploy_logs_swift_days_to_expire',
                default=30,
+               mutable=True,
                help=_('Number of days before a log object is marked as '
                       'expired in Swift. If None, the logs will be kept '
                       'forever or until manually deleted. Used when the '
@@ -96,6 +103,7 @@ opts = [
                                    'from HTTP service served at conductor '
                                    'nodes.'))],
                default='swift',
+               mutable=True,
                help=_('Specifies whether direct deploy interface should try '
                       'to use the image source directly or if ironic should '
                       'cache the image on the conductor and serve it from '
@@ -104,6 +112,7 @@ opts = [
                       'service.')),
     cfg.IntOpt('command_timeout',
                default=60,
+               mutable=True,
                help=_('Timeout (in seconds) for IPA commands. '
                       'Please note, the bootloader installation command '
                       'to the agent is permitted a timeout of twice the '
@@ -116,6 +125,7 @@ opts = [
                       'problems.')),
     cfg.IntOpt('neutron_agent_poll_interval',
                default=2,
+               mutable=True,
                help=_('The number of seconds Neutron agent will wait between '
                       'polling for device changes. This value should be '
                       'the same as CONF.AGENT.polling_interval in Neutron '
diff --git a/ironic/conf/api.py b/ironic/conf/api.py
index bda28d55a..80a30acfc 100644
--- a/ironic/conf/api.py
+++ b/ironic/conf/api.py
@@ -28,9 +28,11 @@ opts = [
                 help=_('The TCP port on which ironic-api listens.')),
     cfg.IntOpt('max_limit',
                default=1000,
+               mutable=True,
                help=_('The maximum number of items returned in a single '
                       'response from a collection resource.')),
     cfg.StrOpt('public_endpoint',
+               mutable=True,
                help=_("Public URL to use when building the links to the API "
                       "resources (for example, \"https://ironic.rocks:6384\")."
                       " If None the links will be built using the request's "
@@ -57,10 +59,12 @@ opts = [
                        "to set URLs in responses to the SSL terminated one.")),
     cfg.BoolOpt('restrict_lookup',
                 default=True,
+                mutable=True,
                 help=_('Whether to restrict the lookup API to only nodes '
                        'in certain states.')),
     cfg.IntOpt('ramdisk_heartbeat_timeout',
                default=300,
+               mutable=True,
                help=_('Maximum interval (in seconds) for agent heartbeats.')),
 ]
 
diff --git a/ironic/conf/conductor.py b/ironic/conf/conductor.py
index da98678a6..beab8ffcc 100644
--- a/ironic/conf/conductor.py
+++ b/ironic/conf/conductor.py
@@ -46,6 +46,7 @@ opts = [
                # We're using timedelta which can overflow if somebody sets this
                # too high, so limit to a sane value of 10 years.
                max=315576000,
+               mutable=True,
                help=_('Maximum time (in seconds) since the last check-in '
                       'of a conductor. A conductor is considered inactive '
                       'when this time has been exceeded.')),
@@ -74,6 +75,7 @@ opts = [
                       'a deploy ramdisk. Set to 0 to disable timeout.')),
     cfg.BoolOpt('force_power_state_during_sync',
                 default=True,
+                mutable=True,
                 help=_('During sync_power_state, should the hardware power '
                        'state be set to the state recorded in the database '
                        '(True) or should the database be updated based on '
@@ -162,6 +164,7 @@ opts = [
                       '0 - unlimited.')),
     cfg.BoolOpt('automated_clean',
                 default=True,
+                mutable=True,
                 help=_('Enables or disables automated cleaning. Automated '
                        'cleaning is a configurable set of steps, '
                        'such as erasing disk drives, that are performed on '
@@ -206,10 +209,12 @@ opts = [
     cfg.IntOpt('soft_power_off_timeout',
                default=600,
                min=1,
+               mutable=True,
                help=_('Timeout (in seconds) of soft reboot and soft power '
                       'off operation. This value always has to be positive.')),
     cfg.IntOpt('power_state_change_timeout',
                min=2, default=60,
+               mutable=True,
                help=_('Number of seconds to wait for power operations to '
                       'complete, i.e., so that a baremetal node is in the '
                       'desired power state. If timed out, the power operation '
@@ -255,11 +260,13 @@ opts = [
     cfg.StrOpt('rescue_password_hash_algorithm',
                default='sha256',
                choices=['sha256', 'sha512'],
+               mutable=True,
                help=_('Password hash algorithm to be used for the rescue '
                       'password.')),
     cfg.BoolOpt('require_rescue_password_hashed',
                 # TODO(TheJulia): Change this to True in Victoria.
                 default=False,
+                mutable=True,
                 help=_('Option to cause the conductor to not fallback to '
                        'an un-hashed version of the rescue password, '
                        'permitting rescue with older ironic-python-agent '
diff --git a/ironic/conf/default.py b/ironic/conf/default.py
index 9621c2db5..b26e84abc 100644
--- a/ironic/conf/default.py
+++ b/ironic/conf/default.py
@@ -72,6 +72,7 @@ api_opts = [
                 help=_('Enable pecan debug mode. WARNING: this is insecure '
                        'and should not be used in a production environment.')),
     cfg.StrOpt('default_resource_class',
+               mutable=True,
                help=_('Resource class to use for new nodes when no resource '
                       'class is provided in the creation request.')),
 ]
@@ -191,6 +192,7 @@ hash_opts = [
 image_opts = [
     cfg.BoolOpt('force_raw_images',
                 default=True,
+                mutable=True,
                 help=_('If True, convert backing images to "raw" disk image '
                        'format.')),
     cfg.StrOpt('isolinux_bin',
@@ -231,6 +233,7 @@ image_opts = [
 img_cache_opts = [
     cfg.BoolOpt('parallel_image_downloads',
                 default=False,
+                mutable=True,
                 help=_('Run image downloads and raw format conversions in '
                        'parallel.')),
 ]
@@ -304,6 +307,7 @@ path_opts = [
 portgroup_opts = [
     cfg.StrOpt(
         'default_portgroup_mode', default='active-backup',
+        mutable=True,
         help=_(
             'Default mode for portgroups. Allowed values can be found in the '
             'linux kernel documentation on bonding: '
@@ -340,6 +344,7 @@ service_opts = [
                       'conductor and API services')),
     cfg.BoolOpt('require_agent_token',
                 default=False,
+                mutable=True,
                 help=_('Used to require the use of agent tokens. These '
                        'tokens are used to guard the api lookup endpoint and '
                        'conductor heartbeat processing logic to authenticate '
diff --git a/ironic/conf/deploy.py b/ironic/conf/deploy.py
index 500324f1c..8be4758b0 100644
--- a/ironic/conf/deploy.py
+++ b/ironic/conf/deploy.py
@@ -29,15 +29,18 @@ opts = [
                help=_("ironic-conductor node's HTTP root path.")),
     cfg.BoolOpt('enable_ata_secure_erase',
                 default=True,
+                mutable=True,
                 help=_('Whether to support the use of ATA Secure Erase '
                        'during the cleaning process. Defaults to True.')),
     cfg.IntOpt('erase_devices_priority',
+               mutable=True,
                help=_('Priority to run in-band erase devices via the Ironic '
                       'Python Agent ramdisk. If unset, will use the priority '
                       'set in the ramdisk (defaults to 10 for the '
                       'GenericHardwareManager). If set to 0, will not run '
                       'during cleaning.')),
     cfg.IntOpt('erase_devices_metadata_priority',
+               mutable=True,
                help=_('Priority to run in-band clean step that erases '
                       'metadata from devices, via the Ironic Python Agent '
                       'ramdisk. If unset, will use the priority set in the '
@@ -47,11 +50,13 @@ opts = [
     cfg.IntOpt('shred_random_overwrite_iterations',
                default=1,
                min=0,
+               mutable=True,
                help=_('During shred, overwrite all block devices N times with '
                       'random data. This is only used if a device could not '
                       'be ATA Secure Erased. Defaults to 1.')),
     cfg.BoolOpt('shred_final_overwrite_with_zeros',
                 default=True,
+                mutable=True,
                 help=_("Whether to write zeros to a node's block devices "
                        "after writing random data. This will write zeros to "
                        "the device even when "
@@ -60,6 +65,7 @@ opts = [
                        "Secure Erased. Defaults to True.")),
     cfg.BoolOpt('continue_if_disk_secure_erase_fails',
                 default=False,
+                mutable=True,
                 help=_('Defines what to do if an ATA secure erase operation '
                        'fails during cleaning in the Ironic Python Agent. '
                        'If False, the cleaning operation will fail and the '
@@ -69,18 +75,21 @@ opts = [
     cfg.IntOpt('disk_erasure_concurrency',
                default=1,
                min=1,
+               mutable=True,
                help=_('Defines the target pool size used by Ironic Python '
                       'Agent ramdisk to erase disk devices. The number of '
                       'threads created to erase disks will not exceed this '
                       'value or the number of disks to be erased.')),
     cfg.BoolOpt('power_off_after_deploy_failure',
                 default=True,
+                mutable=True,
                 help=_('Whether to power off a node after deploy failure. '
                        'Defaults to True.')),
     cfg.StrOpt('default_boot_option',
                choices=[('netboot', _('boot from a network')),
                         ('local', _('local boot'))],
                default='local',
+               mutable=True,
                help=_('Default boot option to use when no boot option is '
                       'requested in node\'s driver_info. Defaults to '
                       '"local". Prior to the Ussuri release, the default '
@@ -89,6 +98,7 @@ opts = [
                choices=[(boot_modes.UEFI, _('UEFI boot mode')),
                         (boot_modes.LEGACY_BIOS, _('Legacy BIOS boot mode'))],
                default=boot_modes.LEGACY_BIOS,
+               mutable=True,
                help=_('Default boot mode to use when no boot mode is '
                       'requested in node\'s driver_info, capabilities or '
                       'in the `instance_info` configuration. Currently the '
@@ -103,6 +113,7 @@ opts = [
                 default=False,
                 deprecated_group='conductor',
                 deprecated_name='configdrive_use_swift',
+                mutable=True,
                 help=_('Whether to upload the config drive to object store. '
                        'Set this option to True to store config drive '
                        'in a swift endpoint.')),
@@ -115,6 +126,7 @@ opts = [
                       'instead of swift tempurls.')),
     cfg.BoolOpt('fast_track',
                 default=False,
+                mutable=True,
                 help=_('Whether to allow deployment agents to perform lookup, '
                        'heartbeat operations during initial states of a '
                        'machine lifecycle and by-pass the normal setup '
@@ -127,6 +139,7 @@ opts = [
                default=300,
                min=0,
                max=300,
+               mutable=True,
                help=_('Seconds for which the last heartbeat event is to be '
                       'considered valid for the purpose of a fast '
                       'track sequence. This setting should generally be '
diff --git a/ironic/conf/ipmi.py b/ironic/conf/ipmi.py
index 9545bde17..3ca28054c 100644
--- a/ironic/conf/ipmi.py
+++ b/ironic/conf/ipmi.py
@@ -22,6 +22,7 @@ from ironic.common.i18n import _
 opts = [
     cfg.IntOpt('command_retry_timeout',
                default=60,
+               mutable=True,
                help=_('Maximum time in seconds to retry retryable IPMI '
                       'operations. (An operation is retryable, for '
                       'example, if the requested operation fails '
@@ -31,18 +32,21 @@ opts = [
                       'unresponsive BMCs.')),
     cfg.IntOpt('min_command_interval',
                default=5,
+               mutable=True,
                help=_('Minimum time, in seconds, between IPMI operations '
                       'sent to a server. There is a risk with some hardware '
                       'that setting this too low may cause the BMC to crash. '
                       'Recommended setting is 5 seconds.')),
     cfg.BoolOpt('kill_on_timeout',
                 default=True,
+                mutable=True,
                 help=_('Kill `ipmitool` process invoked by ironic to read '
                        'node power state if `ipmitool` process does not exit '
                        'after `command_retry_timeout` timeout expires. '
                        'Recommended setting is True')),
     cfg.BoolOpt('disable_boot_timeout',
                 default=True,
+                mutable=True,
                 help=_('Default timeout behavior whether ironic sends a raw '
                        'IPMI command to disable the 60 second timeout for '
                        'booting. Setting this option to False will NOT send '
@@ -51,10 +55,12 @@ opts = [
                        'option in node\'s \'driver_info\' field.')),
     cfg.MultiStrOpt('additional_retryable_ipmi_errors',
                     default=[],
+                    mutable=True,
                     help=_('Additional errors ipmitool may encounter, '
                            'specific to the environment it is run in.')),
     cfg.BoolOpt('debug',
                 default=False,
+                mutable=True,
                 help=_('Enables all ipmi commands to be executed with an '
                        'additional debugging output. This is a separate '
                        'option as ipmitool can log a substantial amount '
diff --git a/ironic/conf/iscsi.py b/ironic/conf/iscsi.py
index 8b1a258e0..5e977e72c 100644
--- a/ironic/conf/iscsi.py
+++ b/ironic/conf/iscsi.py
@@ -21,9 +21,11 @@ from ironic.common.i18n import _
 opts = [
     cfg.PortOpt('portal_port',
                 default=3260,
+                mutable=True,
                 help=_('The port number on which the iSCSI portal listens '
                        'for incoming connections.')),
     cfg.StrOpt('conv_flags',
+               mutable=True,
                help=_('Flags that need to be sent to the dd command, '
                       'to control the conversion of the original file '
                       'when copying to the host. It can contain several '
@@ -31,6 +33,7 @@ opts = [
     cfg.IntOpt('verify_attempts',
                default=3,
                min=1,
+               mutable=True,
                help=_('Maximum attempts to verify an iSCSI connection is '
                       'active, sleeping 1 second between attempts. Defaults '
                       'to 3.')),
diff --git a/ironic/conf/neutron.py b/ironic/conf/neutron.py
index 377599636..d90395f52 100644
--- a/ironic/conf/neutron.py
+++ b/ironic/conf/neutron.py
@@ -23,12 +23,15 @@ opts = [
     cfg.IntOpt('port_setup_delay',
                default=0,
                min=0,
+               mutable=True,
                help=_('Delay value to wait for Neutron agents to setup '
                       'sufficient DHCP configuration for port.')),
     cfg.IntOpt('retries',
                default=3,
+               mutable=True,
                help=_('Client retries in the case of a failed request.')),
     cfg.StrOpt('cleaning_network',
+               mutable=True,
                help=_('Neutron network UUID or name for the ramdisk to be '
                       'booted into for cleaning nodes. Required for "neutron" '
                       'network interface. It is also required if cleaning '
@@ -37,6 +40,7 @@ opts = [
                       'unique among all networks or cleaning will fail.'),
                deprecated_name='cleaning_network_uuid'),
     cfg.StrOpt('provisioning_network',
+               mutable=True,
                help=_('Neutron network UUID or name for the ramdisk to be '
                       'booted into for provisioning nodes. Required for '
                       '"neutron" network interface. If a name is provided, '
@@ -45,6 +49,7 @@ opts = [
                deprecated_name='provisioning_network_uuid'),
     cfg.ListOpt('provisioning_network_security_groups',
                 default=[],
+                mutable=True,
                 help=_('List of Neutron Security Group UUIDs to be '
                        'applied during provisioning of the nodes. '
                        'Optional for the "neutron" network interface and not '
@@ -53,6 +58,7 @@ opts = [
                        'is used.')),
     cfg.ListOpt('cleaning_network_security_groups',
                 default=[],
+                mutable=True,
                 help=_('List of Neutron Security Group UUIDs to be '
                        'applied during cleaning of the nodes. '
                        'Optional for the "neutron" network interface and not '
@@ -60,6 +66,7 @@ opts = [
                        'If not specified, default security group '
                        'is used.')),
     cfg.StrOpt('rescuing_network',
+               mutable=True,
                help=_('Neutron network UUID or name for booting the ramdisk '
                       'for rescue mode. This is not the network that the '
                       'rescue ramdisk will use post-boot -- the tenant '
@@ -70,6 +77,7 @@ opts = [
                       'among all networks or rescue will fail.')),
     cfg.ListOpt('rescuing_network_security_groups',
                 default=[],
+                mutable=True,
                 help=_('List of Neutron Security Group UUIDs to be applied '
                        'during the node rescue process. Optional for the '
                        '"neutron" network interface and not used for the '
@@ -77,6 +85,7 @@ opts = [
                        'specified, the default security group is used.')),
     cfg.IntOpt('request_timeout',
                default=45,
+               mutable=True,
                help=_('Timeout for request processing when interacting '
                       'with Neutron. This value should be increased if '
                       'neutron port action timeouts are observed as neutron '
@@ -85,18 +94,21 @@ opts = [
                       'client/server interactions.')),
     cfg.BoolOpt('add_all_ports',
                 default=False,
+                mutable=True,
                 help=_('Option to enable transmission of all ports '
                        'to neutron when creating ports for provisioning, '
                        'cleaning, or rescue. This is done without IP '
                        'addresses assigned to the port, and may be useful '
                        'in some bonded network configurations.')),
     cfg.StrOpt('inspection_network',
+               mutable=True,
                help=_('Neutron network UUID or name for the ramdisk to be '
                       'booted into for in-band inspection of nodes. '
                       'If a name is provided, it must be unique among all '
                       'networks or inspection will fail.')),
     cfg.ListOpt('inspection_network_security_groups',
                 default=[],
+                mutable=True,
                 help=_('List of Neutron Security Group UUIDs to be applied '
                        'during the node inspection process. Optional for the '
                        '"neutron" network interface and not used for the '
@@ -104,6 +116,7 @@ opts = [
                        'specified, the default security group is used.')),
     cfg.IntOpt('dhcpv6_stateful_address_count',
                default=4,
+               mutable=True,
                help=_('Number of IPv6 addresses to allocate for ports created '
                       'for provisioning, cleaning, rescue or inspection on '
                       'DHCPv6-stateful networks. Different stages of the '
diff --git a/ironic/conf/nova.py b/ironic/conf/nova.py
index 9fc8c1c52..0ec1f2a77 100644
--- a/ironic/conf/nova.py
+++ b/ironic/conf/nova.py
@@ -18,6 +18,7 @@ from ironic.conf import auth
 opts = [
     cfg.BoolOpt('send_power_notifications',
                 default=True,
+                mutable=True,
                 help=_('When set to True, it will enable the support '
                        'for power state change callbacks to nova. This '
                        'option should be set to False in deployments '
diff --git a/ironic/conf/pxe.py b/ironic/conf/pxe.py
index a54beefa6..1a86237a7 100644
--- a/ironic/conf/pxe.py
+++ b/ironic/conf/pxe.py
@@ -23,9 +23,11 @@ from ironic.common.i18n import _
 opts = [
     cfg.StrOpt('pxe_append_params',
                default='nofb nomodeset vga=normal',
+               mutable=True,
                help=_('Additional append parameters for baremetal PXE boot.')),
     cfg.StrOpt('default_ephemeral_format',
                default='ext4',
+               mutable=True,
                help=_('Default file system format for ephemeral partition, '
                       'if one is created.')),
     cfg.StrOpt('images_path',
@@ -50,16 +52,19 @@ opts = [
     cfg.StrOpt('pxe_config_template',
                default=os.path.join(
                    '$pybasedir', 'drivers/modules/pxe_config.template'),
+               mutable=True,
                help=_('On ironic-conductor node, template file for PXE '
                       'configuration.')),
     cfg.StrOpt('uefi_pxe_config_template',
                default=os.path.join(
                    '$pybasedir',
                    'drivers/modules/pxe_grub_config.template'),
+               mutable=True,
                help=_('On ironic-conductor node, template file for PXE '
                       'configuration for UEFI boot loader.')),
     cfg.DictOpt('pxe_config_template_by_arch',
                 default={},
+                mutable=True,
                 help=_('On ironic-conductor node, template file for PXE '
                        'configuration per node architecture. '
                        'For example: '
@@ -129,10 +134,12 @@ opts = [
                default='4',
                choices=[('4', _('IPv4')),
                         ('6', _('IPv6'))],
+               mutable=True,
                help=_('The IP version that will be used for PXE booting. '
                       'Defaults to 4. EXPERIMENTAL')),
     cfg.BoolOpt('ipxe_use_swift',
                 default=False,
+                mutable=True,
                 help=_("Download deploy and rescue images directly from swift "
                        "using temporary URLs. "
                        "If set to false (default), images are downloaded "
diff --git a/ironic/conf/redfish.py b/ironic/conf/redfish.py
index af1b06451..7310b5a51 100644
--- a/ironic/conf/redfish.py
+++ b/ironic/conf/redfish.py
@@ -46,6 +46,7 @@ opts = [
                help=_('Redfish HTTP client authentication method.')),
     cfg.BoolOpt('use_swift',
                 default=True,
+                mutable=True,
                 help=_('Upload generated ISO images for virtual media boot to '
                        'Swift, then pass temporary URL to BMC for booting the '
                        'node. If set to false, images are placed on the '
@@ -53,15 +54,18 @@ opts = [
                        'local HTTP server.')),
     cfg.StrOpt('swift_container',
                default='ironic_redfish_container',
+               mutable=True,
                help=_('The Swift container to store Redfish driver data. '
                       'Applies only when `use_swift` is enabled.')),
     cfg.IntOpt('swift_object_expiry_timeout',
                default=900,
+               mutable=True,
                help=_('Amount of time in seconds for Swift objects to '
                       'auto-expire. Applies only when `use_swift` is '
                       'enabled.')),
     cfg.StrOpt('kernel_append_params',
                default='nofb nomodeset vga=normal',
+               mutable=True,
                help=_('Additional kernel parameters to pass down to the '
                       'instance kernel. These parameters can be consumed by '
                       'the kernel or by the applications by reading '
diff --git a/ironic/drivers/modules/deploy_utils.py b/ironic/drivers/modules/deploy_utils.py
index cb0af75c8..df369207a 100644
--- a/ironic/drivers/modules/deploy_utils.py
+++ b/ironic/drivers/modules/deploy_utils.py
@@ -838,7 +838,7 @@ class InstanceImageCache(image_cache.ImageCache):
 
 
 @METRICS.timer('cache_instance_image')
-def cache_instance_image(ctx, node, force_raw=CONF.force_raw_images):
+def cache_instance_image(ctx, node, force_raw=None):
     """Fetch the instance's image from Glance
 
     This method pulls the AMI and writes them to the appropriate place
@@ -850,6 +850,10 @@ def cache_instance_image(ctx, node, force_raw=CONF.force_raw_images):
     :returns: a tuple containing the uuid of the image and the path in
         the filesystem where image is cached.
     """
+    # NOTE(dtantsur): applying the default here to make the option mutable
+    if force_raw is None:
+        force_raw = CONF.force_raw_images
+
     i_info = parse_instance_info(node)
     fileutils.ensure_tree(_get_image_dir_path(node.uuid))
     image_path = _get_image_file_path(node.uuid)
diff --git a/ironic/drivers/modules/iscsi_deploy.py b/ironic/drivers/modules/iscsi_deploy.py
index c76d9e154..4d8bdd8d8 100644
--- a/ironic/drivers/modules/iscsi_deploy.py
+++ b/ironic/drivers/modules/iscsi_deploy.py
@@ -283,6 +283,8 @@ def deploy_partition_image(
               NOTE: If key exists but value is None, it means partition doesn't
               exist.
     """
+    # NOTE(dtantsur): CONF.default_boot_option is mutable, don't use it in
+    # the function signature!
     boot_option = boot_option or deploy_utils.get_default_boot_option()
     image_mb = disk_utils.get_image_mb(image_path)
     if image_mb > root_mb:
diff --git a/releasenotes/notes/reloadable-301ec2aa421abf66.yaml b/releasenotes/notes/reloadable-301ec2aa421abf66.yaml
new file mode 100644
index 000000000..c952d473e
--- /dev/null
+++ b/releasenotes/notes/reloadable-301ec2aa421abf66.yaml
@@ -0,0 +1,48 @@
+---
+other:
+  - |
+    The following configuration options can now be reloaded without restarting
+    ironic:
+
+    From ``[agent]``: ``memory_consumed_by_agent``, ``stream_raw_images``,
+    ``deploy_logs_*``, ``image_download_source``, ``command_timeout``
+    and ``neutron_agent_poll_interval``.
+
+    From ``[api]``: ``max_limit``, ``public_endpoint``
+    and ``ramdisk_heartbeat_timeout``.
+
+    From ``[conductor]``: ``heartbeat_timeout``,
+    ``force_power_state_during_sync``, ``automated_clean``,
+    ``soft_power_off_timeout``, ``power_state_change_timeout``,
+    ``rescue_password_hash_algorithm`` and ``require_rescue_password_hashed``.
+
+    From ``[DEFAULT]``: ``default_resource_class``, ``force_raw_images``,
+    ``parallel_image_downloads``, ``default_portgroup_mode``
+    and ``require_agent_token``.
+
+    From ``[deploy]``: ``enable_ata_secure_erase``, ``erase_devices_priority``,
+    ``erase_devices_metadata_priority``, ``shred_random_overwrite_iterations``,
+    ``shred_final_overwrite_with_zeros``,
+    ``continue_if_disk_secure_erase_fails``, ``disk_erasure_concurrency``,
+    ``power_off_after_deploy_failure``, ``default_boot_option``,
+    ``default_boot_mode``, ``configdrive_use_object_store``, ``fast_track``,
+    and ``fast_track_timeout``.
+
+    From ``[ipmi]``: ``kill_on_timeout``, ``disable_boot_timeout``,
+    ``command_retry_interval``, ``min_command_interval``, ``debug``
+    and ``additional_retryable_ipmi_errors``.
+
+    From ``[iscsi]``: ``portal_port``, ``conv_flags`` and ``verify_attempts``.
+
+    From ``[neutron]``: ``port_setup_delay``, ``*_network``,
+    ``*_network_security_groups``, ``request_timeout``, ``add_all_ports``
+    and ``dhcpv6_stateful_address_count``.
+
+    From ``[nova]``: ``send_power_notifications``.
+
+    From ``[pxe]``: ``pxe_append_params``, ``default_ephemeral_format``,
+    ``pxe_config_template``, ``uefi_pxe_config_template``,
+    ``pxe_config_template_by_arch``, ``ip_version`` and ``ipxe_use_swift``.
+
+    From ``[redfish]``: ``use_swift``, ``swift_container``,
+    ``swift_object_expiry_timeout`` and ``kernel_append_params``.