centos7 mysql: mariadb-wait-ready $MAINPID (code=exited, status=1/FAILURE)

 centos7     mysql     

  :#yum remove mariadb* 

 
  
  :#yum -y install mariadb*
  
  ：#systemctl start mariadb.service          
  
      :#systemctl status mariadb -l
  
mariadb.service - MariaDB database server
   Loaded: loaded (/usr/lib/systemd/system/mariadb.service; enabled)
   Active: failed (Result: exit-code) since Wed 2015-01-07 22:47:01 EST; 9s ago
  Process: 19037 ExecStartPost=/usr/libexec/mariadb-wait-ready $MAINPID (code=exited, status=1/FAILURE)
  Process: 19036 ExecStart=/usr/bin/mysqld_safe --basedir=/usr (code=exited, status=0/SUCCESS)
  Process: 19009 ExecStartPre=/usr/libexec/mariadb-prepare-db-dir %n (code=exited, status=0/SUCCESS)
 Main PID: 19036 (code=exited, status=0/SUCCESS)

Jan 07 22:47:00 JX-Store systemd[1]: Starting MariaDB database server...
Jan 07 22:47:00 JX-Store mysqld_safe[19036]: 150107 22:47:00 mysqld_safe Logging to '/var/log/mariadb/mariadb.log'.
Jan 07 22:47:00 JX-Store mysqld_safe[19036]: 150107 22:47:00 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
Jan 07 22:47:00 JX-Store mysqld_safe[19036]: 150107 22:47:00 mysqld_safe mysqld from pid file /var/run/mariadb/mariadb.pid ended
Jan 07 22:47:01 JX-Store systemd[1]: mariadb.service: control process exited, code=exited status=1
Jan 07 22:47:01 JX-Store systemd[1]: Failed to start MariaDB database server.
Jan 07 22:47:01 JX-Store systemd[1]: Unit mariadb.service entered failed state
  
     ，        ，   /var/lib/mysql             
  
  /etc/my.cnf        
  
    :
  
  ，    /var/lib/mysql    /etc/my.cnf          。
  
  
/var/lib/mysql                  ，              :mysql.sock,              mysql