mysql       5843       1 14 10:11 ?        00:00:06 /u01/mysqlA/bin/mariadbd --defaults-file=/usr/service/mariadb/11.5.2/data/my.cnf

=====================================================================================
error point
  - localhost connect fail
=====================================================================================
[root@test4 ~]# mysql -uroot
mysql: Deprecated program name. It will be removed in a future release, use '/u01/mariadb-11.5.2-linux-systemd-x86_64/bin/mariadb' instead
ERROR 2002 (HY000): Can't connect to local server through socket '/tmp/mysql.sock' (2)

[root@test4 ~]# mariadb -uroot
ERROR 2002 (HY000): Can't connect to local server through socket '/tmp/mysql.sock' (2)

[root@test4 ~]# mariadb -uroot --socket=$MARIA_DATA/mysql.sock
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 3
Server version: 11.5.2-MariaDB MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]>
MariaDB [(none)]> create user test@'%' identified by 'welcome1' ;
Query OK, 0 rows affected (0.002 sec)

MariaDB [(none)]> grant all privileges on *.* to test@'%' ;
Query OK, 0 rows affected (0.001 sec)

MariaDB [(none)]> flush privileges ;
Query OK, 0 rows affected (0.000 sec)

MariaDB [(none)]> alter user root@'localhost' identified by 'welcome1' ;
Query OK, 0 rows affected (0.001 sec)

MariaDB [(none)]> flush privileges ;
Query OK, 0 rows affected (0.000 sec)

MariaDB [(none)]> exit

=====================================================================================

=====================================================================================
[root@test4 ~]# mariadb -uroot -pwelcome1
ERROR 2002 (HY000): Can't connect to local server through socket '/tmp/mysql.sock' (2)
[root@test4 ~]# mariadb -uroot -pwelcome1 --socket=$MARIA_DATA/mysql.sock
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 9
Server version: 11.5.2-MariaDB MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]>


=====================================================================================
Connection Test from host(test2) to host(test4)
 - test user : test@'%'
=====================================================================================
[root@test2 ~]# mysql -uroot -pwelcome1
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 13
Server version: 10.11.10-MariaDB-log MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> exit
Bye
[root@test2 ~]# mysql -h192.168.81.154 -P3306 -utest -pwelcome1
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 6
Server version: 11.5.2-MariaDB MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]>

MariaDB [(none)]> select @@hostname ;
+------------+
| @@hostname |
+------------+
| test4      |
+------------+
1 row in set (0.001 sec)