[mysqld]

init_connect='SET collation_connection = utf8mb4_unicode_ci'
init_connect='SET NAMES utf8mb4'
character-set-server  = utf8mb4
character-set-client  = utf8mb4
collation-server      = utf8mb4_unicode_ci
skip-character-set-client-handshake

innodb_file_format     = Barracuda
innodb_file_format_max = Barracuda
innodb_file_per_table  = 1
innodb_large_prefix

===== Result 𝌆

mysql> show variables like 'innodb_file%';
+--------------------------+-----------+
| Variable_name            | Value     |
+--------------------------+-----------+
| innodb_file_format       | Barracuda |
| innodb_file_format_check | ON        |
| innodb_file_format_max   | Barracuda |
| innodb_file_per_table    | ON        |
+--------------------------+-----------+
4 rows in set (0.00 sec)

mysql> show variables like 'collation%';
+----------------------+--------------------+
| Variable_name        | Value              |
+----------------------+--------------------+
| collation_connection | utf8mb4_unicode_ci |
| collation_database   | utf8mb4_unicode_ci |
| collation_server     | utf8mb4_unicode_ci |
+----------------------+--------------------+
3 rows in set (0.00 sec)

mysql> show variables like '%char%';
+--------------------------+----------------------------------------------------------------------+
| Variable_name            | Value                                                                |
+--------------------------+----------------------------------------------------------------------+
| character_set_client     | utf8mb4                                                              |
| character_set_connection | utf8mb4                                                              |
| character_set_database   | utf8mb4                                                              |
| character_set_filesystem | binary                                                               |
| character_set_results    | utf8mb4                                                              |
| character_set_server     | utf8mb4                                                              |
| character_set_system     | utf8                                                                 |
| character_sets_dir       | /usr/local/Cellar/percona-server/5.6.12-rc60.4/share/mysql/charsets/ |
+--------------------------+----------------------------------------------------------------------+
8 rows in set (0.00 sec)