'metrics' pool is missing on major upgrade from Red Hat OpenStack Platform 9 to 10

Issue

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After a major upgrade from OSP 9 to 10, the metrics pool is not configured in Ceph.

From /var/log/gnocchi/metricd.log

2017-09-13 15:17:45.479 603330 INFO gnocchi.storage.ceph [-] Ceph storage backend use 'cradox' python library
2017-09-13 15:17:45.487 603330 ERROR cotyledon [-] Unhandled exception
2017-09-13 15:17:45.487 603330 ERROR cotyledon Traceback (most recent call last):
2017-09-13 15:17:45.487 603330 ERROR cotyledon   File "/usr/lib/python2.7/site-packages/cotyledon/__init__.py", line 52, in _exit_on_exception
2017-09-13 15:17:45.487 603330 ERROR cotyledon     yield
2017-09-13 15:17:45.487 603330 ERROR cotyledon   File "/usr/lib/python2.7/site-packages/cotyledon/__init__.py", line 130, in _run
2017-09-13 15:17:45.487 603330 ERROR cotyledon     self.run()
2017-09-13 15:17:45.487 603330 ERROR cotyledon   File "/usr/lib/python2.7/site-packages/gnocchi/cli.py", line 92, in run
2017-09-13 15:17:45.487 603330 ERROR cotyledon     self._configure()
2017-09-13 15:17:45.487 603330 ERROR cotyledon   File "/usr/lib/python2.7/site-packages/gnocchi/cli.py", line 87, in _configure
2017-09-13 15:17:45.487 603330 ERROR cotyledon     self.store = storage.get_driver(self.conf)
2017-09-13 15:17:45.487 603330 ERROR cotyledon   File "/usr/lib/python2.7/site-packages/gnocchi/storage/__init__.py", line 159, in get_driver
2017-09-13 15:17:45.487 603330 ERROR cotyledon     return get_driver_class(conf)(conf.storage)
2017-09-13 15:17:45.487 603330 ERROR cotyledon   File "/usr/lib/python2.7/site-packages/gnocchi/storage/ceph.py", line 99, in __init__
2017-09-13 15:17:45.487 603330 ERROR cotyledon     self.ioctx = self.rados.open_ioctx(self.pool)
2017-09-13 15:17:45.487 603330 ERROR cotyledon   File "cradox.pyx", line 413, in cradox.requires.wrapper.validate_func (cradox.c:4188)
2017-09-13 15:17:45.487 603330 ERROR cotyledon   File "cradox.pyx", line 1047, in cradox.Rados.open_ioctx (cradox.c:12325)
2017-09-13 15:17:45.487 603330 ERROR cotyledon ObjectNotFound: error opening pool 'metrics'
2017-09-13 15:17:45.487 603330 ERROR cotyledon

This causes several issues.

First, this causes https://access.redhat.com/solutions/3066751
Secondly, the absence of the metrics pool in RHOSP after an upgrade of OSP 9 to OSP 10 causes gnocchi to create too many connections to redis. These connections exhaust the number of sockets on the system due to too many sockets in the TIME_WAIT state. This leads to a rabbitmq failure, because it cannot open new ports.