1. ERROR 2061 (HY000): Authentication plugin 'caching_sha2_password' reported error: Authentication requires secure connection.

【分析】mysql8默认使用插件caching_sha2_password,有些client连接报这个错误，需要拿到server的public key来加密password。

【解决】加参数可以解决：--get-server-public-key

 mysql -u sha2user -p --get-server-public-key。做主从复制的时候也会碰到这种情况，加餐get_master_public_key=1;

 change master to 

    master_host='192.168.2.135',

    master_port=3306,

    master_user='repl_user',

    master_password='123456',

    master_auto_position=1 ,

    get_master_public_key=1;

2.Multiple files found for the same tablespace ID:

2019-10-22T15:27:22.848885+08:00 1 [ERROR] [MY-012209] [InnoDB] Multiple files found for the same tablespace ID:

2019-10-22T15:27:22.848904+08:00 1 [ERROR] [MY-012202] [InnoDB] Tablespace ID: 1 = ['sys/sys_config.ibd', 'sys/sys_config.ibd']

2019-10-22T15:27:22.848915+08:00 1 [ERROR] [MY-012202] [InnoDB] Tablespace ID: 15 = ['test/t.ibd', 'test/t.ibd']

2019-10-22T15:27:22.848922+08:00 1 [ERROR] [MY-012202] [InnoDB] Tablespace ID: 4294967278 = ['undo_002', 'undo_002']

2019-10-22T15:27:22.848932+08:00 1 [ERROR] [MY-012202] [InnoDB] Tablespace ID: 4294967279 = ['undo_001', 'undo_001']

2019-10-22T15:27:22.848939+08:00 1 [ERROR] [MY-012202] [InnoDB] Tablespace ID: 4294967294 = ['mysql.ibd', 'mysql.ibd']

2019-10-22T15:27:22.848952+08:00 1 [ERROR] [MY-012930] [InnoDB] Plugin initialization aborted with error Failed, retry may succeed.

2019-10-22T15:27:22.849080+08:00 1 [ERROR] [MY-010334] [Server] Failed to initialize DD Storage Engine

2019-10-22T15:27:22.849297+08:00 0 [ERROR] [MY-010020] [Server] Data Dictionary initialization failed.

【解答】启动文件加参数innodb_directories="/data/mysqldata;"