It didn't hang though.

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Setting up maas-dns (2.0.0~rc3+bzr5180-0ubuntu2~16.04.1) ...
Setting up postgresql (9.5+173) ...
Setting up maas-region-controller (2.0.0~rc3+bzr5180-0ubuntu2~16.04.1) ...
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/django/db/backends/base/base.py", line 130, in ensure_connection
    self.connect()
  File "/usr/lib/python3/dist-packages/django/db/backends/base/base.py", line 119, in connect
    self.connection = self.get_new_connection(conn_params)
  File "/usr/lib/python3/dist-packages/django/db/backends/postgresql_psycopg2/base.py", line 176, in get_new_connection
    connection = Database.connect(**conn_params)
  File "/usr/lib/python3/dist-packages/psycopg2/__init__.py", line 164, in connect
    conn = _connect(dsn, connection_factory=connection_factory, async=async)
psycopg2.OperationalError: FATAL:  password authentication failed for user "maas"
FATAL:  password authentication failed for user "maas"


The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/sbin/maas-region", line 67, in <module>
    main()
  File "/usr/sbin/maas-region", line 63, in main
    run()
  File "/usr/sbin/maas-region", line 51, in run
    management.execute_from_command_line()
  File "/usr/lib/python3/dist-packages/django/core/management/__init__.py", line 354, in execute_from_command_line
    utility.execute()
  File "/usr/lib/python3/dist-packages/django/core/management/__init__.py", line 346, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/lib/python3/dist-packages/django/core/management/base.py", line 394, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/usr/lib/python3/dist-packages/django/core/management/base.py", line 445, in execute
    output = self.handle(*args, **options)
  File "/usr/lib/python3/dist-packages/maasserver/management/commands/dbupgrade.py", line 274, in handle
    if always_south or self._south_needs_to_be_performed(database):
  File "/usr/lib/python3/dist-packages/maasserver/management/commands/dbupgrade.py", line 200, in _south_needs_to_be_performed
    cls._south_was_performed(database) and
  File "/usr/lib/python3/dist-packages/maasserver/management/commands/dbupgrade.py", line 143, in _south_was_performed
    cursor = connections[database].cursor()
  File "/usr/lib/python3/dist-packages/django/db/backends/base/base.py", line 164, in cursor
    cursor = self.make_cursor(self._cursor())
  File "/usr/lib/python3/dist-packages/django/db/backends/base/base.py", line 135, in _cursor
    self.ensure_connection()
  File "/usr/lib/python3/dist-packages/django/db/backends/base/base.py", line 130, in ensure_connection
    self.connect()
  File "/usr/lib/python3/dist-packages/django/db/utils.py", line 98, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/usr/lib/python3/dist-packages/django/utils/six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "/usr/lib/python3/dist-packages/django/db/backends/base/base.py", line 130, in ensure_connection
    self.connect()
  File "/usr/lib/python3/dist-packages/django/db/backends/base/base.py", line 119, in connect
    self.connection = self.get_new_connection(conn_params)
  File "/usr/lib/python3/dist-packages/django/db/backends/postgresql_psycopg2/base.py", line 176, in get_new_connection
    connection = Database.connect(**conn_params)
  File "/usr/lib/python3/dist-packages/psycopg2/__init__.py", line 164, in connect
    conn = _connect(dsn, connection_factory=connection_factory, async=async)
django.db.utils.OperationalError: FATAL:  password authentication failed for user "maas"
FATAL:  password authentication failed for user "maas"

dpkg: error processing package maas-region-controller (--configure):
 subprocess installed post-installation script returned error exit status 1
No apport report written because the error message indicates its a followup error from a previous failure.
                                                                                                          dpkg: dependency problems prevent configuration of maas:
 maas depends on maas-region-controller (= 2.0.0~rc3+bzr5180-0ubuntu2~16.04.1); however:
  Package maas-region-controller is not configured yet.

dpkg: error processing package maas (--configure):
 dependency problems - leaving unconfigured
Setting up python3-bs4 (4.4.1-1) ...
Setting up python3-bson-ext (3.2-1build1) ...
Setting up python3-html5lib (0.999-4) ...
Setting up python3-pam (0.4.2-13.2ubuntu2) ...
Setting up libwebp5:amd64 (0.4.4-1) ...
Setting up libwebpmux1:amd64 (0.4.4-1) ...
Setting up python3-pil:amd64 (3.1.2-0ubuntu1) ...
Setting up python3-sqlparse (0.1.18-1) ...
Processing triggers for libc-bin (2.23-0ubuntu3) ...
Errors were encountered while processing:
 maas-region-controller
 maas
E: Sub-process /usr/bin/dpkg returned an error code (1)
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