While issuing the below command getting the below error...

 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
    Password: 
    Discovering versions from the identity service failed when creating the password plugin. Attempting to determine version from URL.
    Internal Server Error (HTTP 500)

My environment ...

[root@controller ~(keystone_admin)]# cat /etc/centos-release
CentOS Linux release 7.3.1611 (Core) 

centos-release-openstack-ocata-1-2.el7.noarch trying to configure

[root@controller ~(keystone_admin)]# cat admin-openrc 
export OS_USERNAME=admin
export OS_PASSWORD=keystoneadmin
export OS_PROJECT_NAME=admin
export OS_USER_DOMAIN_NAME=Default
export OS_PROJECT_DOMAIN_NAME=Default
export OS_AUTH_URL=http://controller:35357/v3
export OS_IDENTITY_API_VERSION=3
export PS1='[\u@\h \W(keystone_admin)]# '

[root@controller ~(keystone_admin)]# unset OS_AUTH_URL OS_PASSWORD

then running the command for issuing token .. giving error ...

Some error i find on file ...

==> /var/log/httpd/keystone.log <==
2017-08-15 13:06:23.922368 mod_wsgi (pid=1162): Target WSGI script '/usr/bin/keystone-wsgi-public' cannot be loaded as Python module.
2017-08-15 13:06:23.922398 mod_wsgi (pid=1162): Exception occurred processing WSGI script '/usr/bin/keystone-wsgi-public'.
2017-08-15 13:06:23.922428 Traceback (most recent call last):
2017-08-15 13:06:23.922444   File "/usr/bin/keystone-wsgi-public", line 51, in <module>
2017-08-15 13:06:23.922466     application = initialize_public_application()
2017-08-15 13:06:23.922473   File "/usr/lib/python2.7/site-packages/keystone/server/wsgi.py", line 134, in initialize_public_application
2017-08-15 13:06:23.922488     config_files=_get_config_files())
2017-08-15 13:06:23.922497   File "/usr/lib/python2.7/site-packages/keystone/server/wsgi.py", line 53, in initialize_application
2017-08-15 13:06:23.922506     common.configure(config_files=config_files)
2017-08-15 13:06:23.922511   File "/usr/lib/python2.7/site-packages/keystone/server/common.py", line 30, in configure
2017-08-15 13:06:23.922520     keystone.conf.configure()
2017-08-15 13:06:23.922525   File "/usr/lib/python2.7/site-packages/keystone/conf/__init__.py", line 124, in configure
2017-08-15 13:06:23.922533     help='Do not monkey-patch threading system modules.'))
2017-08-15 13:06:23.922554   File "/usr/lib/python2.7/site-packages/oslo_config/cfg.py", line 2292, in __inner
2017-08-15 13:06:23.922572     result = f(self, *args, **kwargs)
2017-08-15 13:06:23.922584   File "/usr/lib/python2.7/site-packages/oslo_config/cfg.py", line 2482, in register_cli_opt
2017-08-15 13:06:23.922601     raise ArgsAlreadyParsedError("cannot register CLI option")
2017-08-15 13:06:23.922710 ArgsAlreadyParsedError: arguments already parsed: cannot register CLI option