diff --git a/doc/source/microversion_testing.rst b/doc/source/microversion_testing.rst
index fa76770..f2c51b3 100644
--- a/doc/source/microversion_testing.rst
+++ b/doc/source/microversion_testing.rst
@@ -366,6 +366,10 @@
 
   .. _2.55: https://docs.openstack.org/nova/latest/reference/api-microversion-history.html#id49
 
+  * `2.57`_
+
+  .. _2.57: https://docs.openstack.org/nova/latest/reference/api-microversion-history.html#id51
+
   * `2.60`_
 
   .. _2.60: https://docs.openstack.org/nova/latest/reference/api-microversion-history.html#id54
diff --git a/releasenotes/notes/16/16.0.0-add-content-type-without-spaces-b2c9b91b257814f3.yaml b/releasenotes/notes/16/16.0.0-add-content-type-without-spaces-b2c9b91b257814f3.yaml
index fc061bc..9ae46fd 100644
--- a/releasenotes/notes/16/16.0.0-add-content-type-without-spaces-b2c9b91b257814f3.yaml
+++ b/releasenotes/notes/16/16.0.0-add-content-type-without-spaces-b2c9b91b257814f3.yaml
@@ -6,4 +6,4 @@
     The lack of these additional content-type will cause defcore test
     to fail for OpenStack public cloud which uses tomcat module in the
     api gateway. The additions are ``application/json;charset=utf-8``,
-    ``text/html;charset=utf-8``,``text/plain;charset=utf-8``
\ No newline at end of file
+    ``text/html;charset=utf-8``, ``text/plain;charset=utf-8``
diff --git a/releasenotes/notes/16/16.0.0-add-tempest-run-combine-option-e94c1049ba8985d5.yaml b/releasenotes/notes/16/16.0.0-add-tempest-run-combine-option-e94c1049ba8985d5.yaml
index 73900ca..e9c3694 100644
--- a/releasenotes/notes/16/16.0.0-add-tempest-run-combine-option-e94c1049ba8985d5.yaml
+++ b/releasenotes/notes/16/16.0.0-add-tempest-run-combine-option-e94c1049ba8985d5.yaml
@@ -1,6 +1,6 @@
 ---
 features:
   - |
-    Adds a new cli option to tempest run, --combine, which is used to indicate
-    you want the subunit stream output combined with the previous run's in
-    the testr repository
+    Adds a new cli option to tempest run, ``--combine``, which is used
+    to indicate you want the subunit stream output combined with the
+    previous run's in the testr repository
diff --git a/releasenotes/notes/16/16.0.0-remove-deprecated-allow_port_security_disabled-option-d0ffaeb2e7817707.yaml b/releasenotes/notes/16/16.0.0-remove-deprecated-allow_port_security_disabled-option-d0ffaeb2e7817707.yaml
index 9d7102f..5b4a96d 100644
--- a/releasenotes/notes/16/16.0.0-remove-deprecated-allow_port_security_disabled-option-d0ffaeb2e7817707.yaml
+++ b/releasenotes/notes/16/16.0.0-remove-deprecated-allow_port_security_disabled-option-d0ffaeb2e7817707.yaml
@@ -1,5 +1,5 @@
 ---
 upgrade:
   - |
-    The deprecated config option 'allow_port_security_disabled' from compute_feature_enabled
-    group has been removed.
+    The deprecated config option ``allow_port_security_disabled`` from
+    ``compute_feature_enabled`` group has been removed.
diff --git a/releasenotes/notes/16/16.0.0-remove-deprecated-compute-validation-config-options-part-2-5cd17b6e0e6cb8a3.yaml b/releasenotes/notes/16/16.0.0-remove-deprecated-compute-validation-config-options-part-2-5cd17b6e0e6cb8a3.yaml
index b4e4dd1..c8b0ca8 100644
--- a/releasenotes/notes/16/16.0.0-remove-deprecated-compute-validation-config-options-part-2-5cd17b6e0e6cb8a3.yaml
+++ b/releasenotes/notes/16/16.0.0-remove-deprecated-compute-validation-config-options-part-2-5cd17b6e0e6cb8a3.yaml
@@ -8,4 +8,4 @@
     - ``compute.ssh_user`` (available as ``validation.image_ssh_user``)
     - ``scenario.ssh_user`` (available as ``validation.image_ssh_user``)
     - ``compute.network_for_ssh`` (available as ``validation.network_for_ssh``)
-    - ``compute.ping_timeout `` (available as ``validation.ping_timeout``)
+    - ``compute.ping_timeout`` (available as ``validation.ping_timeout``)
diff --git a/releasenotes/notes/add-load-list-cmd-35a4a2e6ea0a36fd.yaml b/releasenotes/notes/add-load-list-cmd-35a4a2e6ea0a36fd.yaml
index 403bbad..145e7dd 100644
--- a/releasenotes/notes/add-load-list-cmd-35a4a2e6ea0a36fd.yaml
+++ b/releasenotes/notes/add-load-list-cmd-35a4a2e6ea0a36fd.yaml
@@ -1,7 +1,7 @@
 ---
 features:
   - |
-    Adds a new cli option to tempest run, --load-list <list-file>
+    Adds a new cli option to tempest run, ``--load-list <list-file>``
     to specify target tests to run from a list-file. The list-file
-    supports the output format of the tempest run --list-tests
+    supports the output format of the tempest run ``--list-tests``
     command.
diff --git a/releasenotes/notes/add-save-state-option-5ea67858cbaca969.yaml b/releasenotes/notes/add-save-state-option-5ea67858cbaca969.yaml
index 8fdf4f0..abd2610 100644
--- a/releasenotes/notes/add-save-state-option-5ea67858cbaca969.yaml
+++ b/releasenotes/notes/add-save-state-option-5ea67858cbaca969.yaml
@@ -1,4 +1,5 @@
 ---
 features:
   - |
-    Add --save-state option to allow saving state of cloud before tempest run.
+    Add ``--save-state`` option to allow saving state of cloud before
+    tempest run.
diff --git a/releasenotes/notes/cli-tests-v3fixes-fb38189cefd64213.yaml b/releasenotes/notes/cli-tests-v3fixes-fb38189cefd64213.yaml
index e3443c8..2a0a86c 100644
--- a/releasenotes/notes/cli-tests-v3fixes-fb38189cefd64213.yaml
+++ b/releasenotes/notes/cli-tests-v3fixes-fb38189cefd64213.yaml
@@ -2,8 +2,8 @@
 other:
   - |
     The CLIClient class, when it calls a command line client, uses
-    --os-project-name instead of --os-tenant-name for the project, and
-    passes --os-identity-api-version (default empty).
+    ``--os-project-name`` instead of ``--os-tenant-name`` for the
+    project, and passes ``--os-identity-api-version`` (default empty).
     All CLI clients still available in supported releases of OpenStack
-    which are wrapped by the cmd_with_auth() method support those
+    which are wrapped by the ``cmd_with_auth()`` method support those
     switches.
diff --git a/releasenotes/notes/tempest-run-fix-updates-564b41706decbba1.yaml b/releasenotes/notes/tempest-run-fix-updates-564b41706decbba1.yaml
index 265853d..0f9a0f6 100644
--- a/releasenotes/notes/tempest-run-fix-updates-564b41706decbba1.yaml
+++ b/releasenotes/notes/tempest-run-fix-updates-564b41706decbba1.yaml
@@ -1,8 +1,8 @@
 ---
 features:
   - |
-    Adds a new CLI arg in tempest run, --black-regex, which is a regex to
-    exclude the tests that match it.
+    Adds a new CLI arg in tempest run, ``--black-regex``, which is a
+    regex to exclude the tests that match it.
 fixes:
   - |
     Fixes tempest run CLI args mutually exclusive behavior which should not
diff --git a/releasenotes/notes/tempest-workspace-delete-directory-feature-74d6d157a5a05561.yaml b/releasenotes/notes/tempest-workspace-delete-directory-feature-74d6d157a5a05561.yaml
index ec21098..c69ed50 100644
--- a/releasenotes/notes/tempest-workspace-delete-directory-feature-74d6d157a5a05561.yaml
+++ b/releasenotes/notes/tempest-workspace-delete-directory-feature-74d6d157a5a05561.yaml
@@ -1,5 +1,5 @@
 ---
 features:
   - |
-    Added tempest workspace remove --name <workspace_name> --rmdir
+    Added tempest workspace remove ``--name <workspace_name> --rmdir``
     feature to delete the workspace directory as well as entry.
diff --git a/tempest/api/compute/servers/test_servers_microversions.py b/tempest/api/compute/servers/test_servers_microversions.py
index f3863f1..2434884 100644
--- a/tempest/api/compute/servers/test_servers_microversions.py
+++ b/tempest/api/compute/servers/test_servers_microversions.py
@@ -49,3 +49,18 @@
                                            key_name=keypair_name)
         waiters.wait_for_server_status(self.servers_client,
                                        server['id'], 'ACTIVE')
+
+
+class ServerShowV257Test(base.BaseV2ComputeTest):
+    min_microversion = '2.57'
+    max_microversion = 'latest'
+
+    @decorators.idempotent_id('803df848-080a-4261-8f11-b020cd9b6f60')
+    def test_rebuild_server(self):
+        server = self.create_test_server(wait_until='ACTIVE')
+        user_data = "ZWNobyAiaGVsbG8gd29ybGQi"
+        # Checking rebuild API response schema
+        self.servers_client.rebuild_server(server['id'], self.image_ref_alt,
+                                           user_data=user_data)
+        waiters.wait_for_server_status(self.servers_client,
+                                       server['id'], 'ACTIVE')
diff --git a/tempest/lib/api_schema/response/compute/v2_57/__init__.py b/tempest/lib/api_schema/response/compute/v2_57/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/tempest/lib/api_schema/response/compute/v2_57/__init__.py
diff --git a/tempest/lib/api_schema/response/compute/v2_57/servers.py b/tempest/lib/api_schema/response/compute/v2_57/servers.py
new file mode 100644
index 0000000..ed1ca7d
--- /dev/null
+++ b/tempest/lib/api_schema/response/compute/v2_57/servers.py
@@ -0,0 +1,53 @@
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import copy
+
+from tempest.lib.api_schema.response.compute.v2_54 import servers as servers254
+# ****** Schemas changed in microversion 2.57 *****************
+
+# Note(gmann): This is schema for microversion 2.57 which includes the
+# 'user_data' in the Response body of the following APIs:
+#    - ``POST '/servers/{server_id}/action (rebuild)``
+
+user_data = {
+    'oneOf': [
+        {
+            'type': 'string',
+            'format': 'base64',
+            'maxLength': 65535
+        },
+        {'type': 'null'}
+    ]
+}
+
+rebuild_server = copy.deepcopy(servers254.rebuild_server)
+rebuild_server['response_body']['properties']['server'][
+    'properties'].update({'user_data': user_data})
+rebuild_server['response_body']['properties']['server'][
+    'required'].append('user_data')
+
+rebuild_server_with_admin_pass = copy.deepcopy(
+    servers254.rebuild_server_with_admin_pass)
+rebuild_server_with_admin_pass['response_body']['properties']['server'][
+    'properties'].update({'user_data': user_data})
+rebuild_server_with_admin_pass['response_body']['properties']['server'][
+    'required'].append('user_data')
+
+# ****** Schemas unchanged in microversion 2.57 since microversion 2.54 ***
+
+# NOTE(gmann): Below are the unchanged schema in this microversion. We need
+# to keeo this schema in this file to have the generic way to select the
+# right schema based on self.schema_versions_info mapping in service client.
+get_server = copy.deepcopy(servers254.get_server)
+list_servers_detail = copy.deepcopy(servers254.list_servers_detail)
+update_server = copy.deepcopy(servers254.update_server)
diff --git a/tempest/lib/common/jsonschema_validator.py b/tempest/lib/common/jsonschema_validator.py
index bbdf382..9a35b76 100644
--- a/tempest/lib/common/jsonschema_validator.py
+++ b/tempest/lib/common/jsonschema_validator.py
@@ -12,9 +12,11 @@
 #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 #    License for the specific language governing permissions and limitations
 #    under the License.
+import base64
 
 import jsonschema
 from oslo_utils import timeutils
+import six
 
 # JSON Schema validator and format checker used for JSON Schema validation
 JSONSCHEMA_VALIDATOR = jsonschema.Draft4Validator
@@ -37,3 +39,19 @@
         return False
     else:
         return True
+
+
+@jsonschema.FormatChecker.cls_checks('base64')
+def _validate_base64_format(instance):
+    try:
+        if isinstance(instance, six.text_type):
+            instance = instance.encode('utf-8')
+        base64.decodestring(instance)
+    except base64.binascii.Error:
+        return False
+    except TypeError:
+        # The name must be string type. If instance isn't string type, the
+        # TypeError will be raised at here.
+        return False
+
+    return True
diff --git a/tempest/lib/services/compute/servers_client.py b/tempest/lib/services/compute/servers_client.py
index e75cdb5..f6e0e69 100644
--- a/tempest/lib/services/compute/servers_client.py
+++ b/tempest/lib/services/compute/servers_client.py
@@ -30,6 +30,7 @@
 from tempest.lib.api_schema.response.compute.v2_47 import servers as schemav247
 from tempest.lib.api_schema.response.compute.v2_48 import servers as schemav248
 from tempest.lib.api_schema.response.compute.v2_54 import servers as schemav254
+from tempest.lib.api_schema.response.compute.v2_57 import servers as schemav257
 from tempest.lib.api_schema.response.compute.v2_6 import servers as schemav26
 from tempest.lib.api_schema.response.compute.v2_9 import servers as schemav29
 from tempest.lib.common import rest_client
@@ -49,7 +50,8 @@
         {'min': '2.26', 'max': '2.46', 'schema': schemav226},
         {'min': '2.47', 'max': '2.47', 'schema': schemav247},
         {'min': '2.48', 'max': '2.53', 'schema': schemav248},
-        {'min': '2.54', 'max': None, 'schema': schemav254}]
+        {'min': '2.54', 'max': '2.56', 'schema': schemav254},
+        {'min': '2.57', 'max': None, 'schema': schemav257}]
 
     def __init__(self, auth_provider, service, region,
                  enable_instance_password=True, **kwargs):