ubuntu openstack ocata - Discovering versions from the identity service failed - ubuntu-16.04

Question

command:
openstack --os-auth-url http://controller:5000/v3 \
--os-project-domain-name default --os-user-domain-name default \
--os-project-name demo --os-username demo token issue
error:
Discovering versions from the identity service failed when creating
the password plugin. Attempting to determine version from URL.
Internal Server Error (HTTP 500)
Error coming in keystone.log:
2018-06-12 10:40:05.888577 mod_wsgi (pid=16170): Target WSGI script '/usr/bin/keystone-wsgi-admin' cannot be loaded as Python module.
2018-06-12 10:40:05.888611 mod_wsgi (pid=16170): Exception occurred processing WSGI script '/usr/bin/keystone-wsgi-admin'.
2018-06-12 10:40:05.888634 Traceback (most recent call last):
2018-06-12 10:40:05.888656 File "/usr/bin/keystone-wsgi-admin", line 51, in <module>
2018-06-12 10:40:05.888688 application = initialize_admin_application()
2018-06-12 10:40:05.888702 File "/usr/lib/python2.7/dist-packages/keystone/server/wsgi.py", line 129, in initialize_admin_application
2018-06-12 10:40:05.888726 config_files=_get_config_files())
2018-06-12 10:40:05.888739 File "/usr/lib/python2.7/dist-packages/keystone/server/wsgi.py", line 53, in initialize_application
2018-06-12 10:40:05.888759 common.configure(config_files=config_files)
2018-06-12 10:40:05.888772 File "/usr/lib/python2.7/dist-packages/keystone/server/common.py", line 30, in configure
2018-06-12 10:40:05.888792 keystone.conf.configure()
2018-06-12 10:40:05.888805 File "/usr/lib/python2.7/dist-packages/keystone/conf/__init__.py", line 126, in configure
2018-06-12 10:40:05.888826 help='Do not monkey-patch threading system modules.'))
2018-06-12 10:40:05.888839 File "/usr/lib/python2.7/dist-packages/oslo_config/cfg.py", line 2288, in __inner
2018-06-12 10:40:05.888860 result = f(self, *args, **kwargs)
2018-06-12 10:40:05.888872 File "/usr/lib/python2.7/dist-packages/oslo_config/cfg.py", line 2478, in register_cli_opt
2018-06-12 10:40:05.888892 raise ArgsAlreadyParsedError("cannot register CLI option")
2018-06-12 10:40:05.888915 ArgsAlreadyParsedError: arguments already parsed: cannot register CLI option
error.log:
[Tue Jun 12 10:12:18.510745 2018] [mpm_event:notice] [pid 29892:tid 139804806121344] AH00491: caught SIGTERM, shutting down
[Tue Jun 12 10:12:29.674244 2018] [wsgi:warn] [pid 16158:tid 139690338350976] mod_wsgi: Compiled for Python/2.7.11.
[Tue Jun 12 10:12:29.674304 2018] [wsgi:warn] [pid 16158:tid 139690338350976] mod_wsgi: Runtime using Python/2.7.12.
[Tue Jun 12 10:12:29.676957 2018] [mpm_event:notice] [pid 16158:tid 139690338350976] AH00489: Apache/2.4.18 (Ubuntu) mod_wsgi/4.3.0 Python/2.7.12 configured -- resuming normal operations
[Tue Jun 12 10:12:29.676985 2018] [core:notice] [pid 16158:tid 139690338350976] AH00094: Command line: '/usr/sbin/apache2'
Please can somebody help me to solve the issue.

Answer 1

Issue solved.
Error was in mod_wsgi according to log. Web Service Gateway Interface (WSGI) middleware pipeline for the Identity service is configured in keystone-paste.ini file, thus verified my file with the openstack docs keystone-paste.ini file available on internet thus changed pipeline configuration and issue get solved.
I have edited /etc/keystone/keystone-paste.ini file
Under [pipeline:public_api]
pipeline = healthcheck cors sizelimit http_proxy_to_wsgi osprofiler url_normalize request_id
changed above line to:
pipeline = healthcheck cors sizelimit http_proxy_to_wsgi osprofiler url_normalize request_id build_auth_context token_auth json_body ec2_extension public_service
Same way edited [pipeline:admin_api]
pipeline = healthcheck cors sizelimit http_proxy_to_wsgi osprofiler url_normalize request_id
changed pipeline to:
pipeline = healthcheck cors sizelimit http_proxy_to_wsgi osprofiler url_normalize request_id build_auth_context token_auth json_body ec2_extension s3_extension admin_service
Also made changes in [pipeline:api_v3]
pipeline = healthcheck cors sizelimit http_proxy_to_wsgi osprofiler url_normalize request_id
changed above line to:
pipeline = healthcheck cors sizelimit http_proxy_to_wsgi osprofiler url_normalize request_id build_auth_context token_auth json_body ec2_extension_v3 s3_extension service_v3
By making following changes issue get solved.