diff --git a/ansible/roles/horizon/templates/local_settings.j2 b/ansible/roles/horizon/templates/local_settings.j2
index 3b7f86aa27..136741b8cf 100644
--- a/ansible/roles/horizon/templates/local_settings.j2
+++ b/ansible/roles/horizon/templates/local_settings.j2
@@ -785,9 +785,16 @@ SECURITY_GROUP_RULES = {
# the enabled panel configuration.
# You should not add settings to this list for out of tree extensions.
# See: https://wiki.openstack.org/wiki/Horizon/RESTAPI
-REST_API_REQUIRED_SETTINGS = ['OPENSTACK_HYPERVISOR_FEATURES',
- 'LAUNCH_INSTANCE_DEFAULTS',
- 'OPENSTACK_IMAGE_FORMATS']
+REST_API_REQUIRED_SETTINGS = [
+ 'CREATE_IMAGE_DEFAULTS',
+ 'DEFAULT_BOOT_SOURCE',
+ 'ENFORCE_PASSWORD_CHECK',
+ 'LAUNCH_INSTANCE_DEFAULTS',
+ 'OPENSTACK_HYPERVISOR_FEATURES',
+ 'OPENSTACK_IMAGE_FORMATS',
+ 'OPENSTACK_KEYSTONE_BACKEND',
+ 'OPENSTACK_KEYSTONE_DEFAULT_DOMAIN',
+]
# Additional settings can be made available to the client side for
# extensibility by specifying them in REST_API_ADDITIONAL_SETTINGS
diff --git a/releasenotes/notes/sync-horizon-rest-api-required-settings-099875e53248b62c.yaml b/releasenotes/notes/sync-horizon-rest-api-required-settings-099875e53248b62c.yaml
new file mode 100644
index 0000000000..519d61c8a3
--- /dev/null
+++ b/releasenotes/notes/sync-horizon-rest-api-required-settings-099875e53248b62c.yaml
@@ -0,0 +1,14 @@
+---
+upgrade:
+ - |
+ The default value of ``REST_API_REQUIRED_SETTINGS`` was synchronized with
+ Horizon. You may want to review settings exposed by the `updated
+ configuration
+ <https://docs.openstack.org/horizon/latest/configuration/settings.html#rest-api-required-settings>`__.
+fixes:
+ - |
+ Updates the default value of ``REST_API_REQUIRED_SETTINGS`` in Horizon
+ ``local_settings``, which enables some features such as `selecting the
+ default boot source for instances
+ <https://docs.openstack.org/horizon/latest/configuration/settings.html#default-boot-source>`__.
+ `LP#1891024 <https://launchpad.net/bugs/1891024>`__