Unable to start cinder-volume service

Issue

• When running cinder service-list, a newly installed cinder-volume server isn't displayed:

[root@controller ~]# cinder service-list
+------------------+-----------------------------+------+---------+-------+----------------------------+-----------------+
|      Binary      |             Host            | Zone |  Status | State |         Updated_at         | Disabled Reason |
+------------------+-----------------------------+------+---------+-------+----------------------------+-----------------+
| cinder-scheduler | controller                  | nova | enabled |   up  | 2016-07-06T21:38:58.000000 |        -        |
+------------------+-----------------------------+------+---------+-------+----------------------------+-----------------+

• In the server where cinder-volume is running there seems to be an issue when connecting to the database:

[root@block1 ~]# tailf /var/log/cinder/volume.log
2016-07-06 17:42:33.867 2222 ERROR cinder.cmd.volume   File "/usr/lib/python2.7/site-packages/oslo_db/sqlalchemy/enginefacade.py", line 362, in _setup_for_connection
2016-07-06 17:42:33.867 2222 ERROR cinder.cmd.volume     sql_connection=sql_connection, **engine_kwargs)
2016-07-06 17:42:33.867 2222 ERROR cinder.cmd.volume   File "/usr/lib/python2.7/site-packages/oslo_db/sqlalchemy/engines.py", line 152, in create_engine
2016-07-06 17:42:33.867 2222 ERROR cinder.cmd.volume     test_conn = _test_connection(engine, max_retries, retry_interval)
2016-07-06 17:42:33.867 2222 ERROR cinder.cmd.volume   File "/usr/lib/python2.7/site-packages/oslo_db/sqlalchemy/engines.py", line 334, in _test_connection
2016-07-06 17:42:33.867 2222 ERROR cinder.cmd.volume     six.reraise(type(de_ref), de_ref)
2016-07-06 17:42:33.867 2222 ERROR cinder.cmd.volume   File "<string>", line 2, in reraise
2016-07-06 17:42:33.867 2222 ERROR cinder.cmd.volume DBConnectionError: (_mysql_exceptions.OperationalError) (2002, "Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)")
2016-07-06 17:42:33.867 2222 ERROR cinder.cmd.volume
2016-07-06 17:42:33.876 2222 ERROR cinder.cmd.volume [-] No volume service(s) started successfully, terminating.