mysql_install_db --auth-root-authentication-method=socket fails to install unix_socket plugin

mysql_install_db  --basedir=/usr/local/mariadb --defaults-file=~/my.cnf --skip-auth-anonymous-user --auth-root-authentication-method=socket  --auth-root-socket-user=danielgb

> mysqld --defaults-file=~/my.cnf

2017-12-04 23:14:10 0 [Note] mysqld (mysqld 10.3.3-MariaDB) starting as process 239421 ...

2017-12-04 23:14:10 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins

2017-12-04 23:14:10 0 [Note] InnoDB: Uses event mutexes

2017-12-04 23:14:10 0 [Note] InnoDB: Compressed tables use zlib 1.2.11

...

2017-12-04 23:20:08 0 [Note] mysqld: ready for connections.

Version: '10.3.3-MariaDB'  socket: '/tmp/mysql.sock'  port: 3306  Source distribution

~> mysql -S /tmp/mysql.sock

ERROR 1524 (HY000): Plugin 'unix_socket' is not loaded

> mysqld --defaults-file=~/my.cnf --skip-grant-tables

...

MariaDB [mysql]> show plugins;

+-------------------------------+----------+--------------------+---------+---------+

| Name                          | Status   | Type               | Library | License |

+-------------------------------+----------+--------------------+---------+---------+

| binlog                        | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |

| mysql_native_password         | ACTIVE   | AUTHENTICATION     | NULL    | GPL     |

| mysql_old_password            | ACTIVE   | AUTHENTICATION     | NULL    | GPL     |

| wsrep                         | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |

| CSV                           | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |

| MEMORY                        | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |

| MyISAM                        | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |

| MRG_MyISAM                    | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |

| CLIENT_STATISTICS             | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INDEX_STATISTICS              | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| TABLE_STATISTICS              | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| USER_STATISTICS               | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| SQL_SEQUENCE                  | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |

| InnoDB                        | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |

| INNODB_TRX                    | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_LOCKS                  | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_LOCK_WAITS             | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_CMP                    | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_CMP_RESET              | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_CMPMEM                 | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_CMPMEM_RESET           | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_CMP_PER_INDEX          | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_CMP_PER_INDEX_RESET    | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_BUFFER_PAGE            | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_BUFFER_PAGE_LRU        | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_BUFFER_POOL_STATS      | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_METRICS                | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_FT_DEFAULT_STOPWORD    | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_FT_DELETED             | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_FT_BEING_DELETED       | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_FT_CONFIG              | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_FT_INDEX_CACHE         | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_FT_INDEX_TABLE         | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_SYS_TABLES             | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_SYS_TABLESTATS         | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_SYS_INDEXES            | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_SYS_COLUMNS            | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_SYS_FIELDS             | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_SYS_FOREIGN            | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_SYS_FOREIGN_COLS       | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_SYS_TABLESPACES        | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_SYS_DATAFILES          | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_SYS_VIRTUAL            | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_MUTEXES                | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_SYS_SEMAPHORE_WAITS    | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| INNODB_TABLESPACES_ENCRYPTION | ACTIVE   | INFORMATION SCHEMA | NULL    | BSD     |

| INNODB_TABLESPACES_SCRUBBING  | ACTIVE   | INFORMATION SCHEMA | NULL    | BSD     |

| Aria                          | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |

| PERFORMANCE_SCHEMA            | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |

| SEQUENCE                      | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |

| FEEDBACK                      | DISABLED | INFORMATION SCHEMA | NULL    | GPL     |

| user_variables                | ACTIVE   | INFORMATION SCHEMA | NULL    | GPL     |

| partition                     | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |

+-------------------------------+----------+--------------------+---------+---------+

53 rows in set (0.001 sec)

MariaDB [mysql]> INSTALL PLUGIN unix_socket SONAME 'auth_socket';

Query OK, 0 rows affected (0.001 sec)