centos8降级centos7安装mysql遇到的问题

luobiaodeMacBook-Air:~ luobiao$ ssh root@39.101.204.8

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!    @

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!

Someone could be eavesdropping on you right now (man-in-the-middle attack)!

It is also possible that a host key has just been changed.

The fingerprint for the ECDSA key sent by the remote host is

SHA256:jN2L7Ebd8ZV03ErBmMpGwHybqNBnLqOX0TTk9TbgzZs.

Please contact your system administrator.

Add correct host key in /Users/luobiao/.ssh/known_hosts to get rid of this message.

Offending ECDSA key in /Users/luobiao/.ssh/known_hosts:8

ECDSA host key for 39.101.204.8 has changed and you have requested strict checking.

Host key verification failed.

解决：

这里面，有一句很关键。

ECDSA host key for 39.101.204.8  has changed and you have requested strict checking.

Host key verification failed.

一般这个问题，是你重置过你的服务器后。你再次想访问会出现这个问题。

ssh-keygen -R  39.101.204.8 

1.安装mysql报错

mysqld: error while loading shared libraries: libaio.so.1: cannot open shared object file: No such file or directory

解决：

经过百度说是缺少 libaio.so.1  这个包.这个包是干什么的呢？

我也没查看到？试试先安装这个包。

yum -y install libaio  

安装后，解决该问题。

2.[ root @later01 /errlog ]# /etc/init.d/mysqld start 

Starting MySQL.2020-04-11T16:49:17.645735Z mysqld_safe error: log-error set to '/errlog/3306/mysql.log', however file don't exists. Create writable for user 'mysql'.

解决： 创建日志文件并赋权 

[ root @later01 /errlog/3306 ]# echo "" >mysql.log 

[ root @later01 /errlog/3306 ]# chown -R mysql.mysql /errlog/

3.2020-04-11T16:52:12.084460Z 0 [ERROR] InnoDB: The innodb_system data file './ibdata1' is of a different size 768 pages (rounded down to MB) than the 4864 pages specified in the .cnf file!

解决：注释my.cnf 中的

#innodb_data_file_path=ibdata1:76Mibdata2:100Mibdata3:100M:autoextend

1．Starting MySQL.Manager of pid-file quit without updating fi[失败]

关于这个错误原因有很多，最大的可能是没有创建测试数据库，可以用/usr/local/mysql/scripts/mysql_install_db –user=mysql命令进行创建；另外一个原因可能是权限设置问题，需要赋予mysql的data权限，可以用chmod -R 命令。

2．FATAL ERROR: Could not find /home/mysql/bin/my_print_defaults If you are using a binary release,you must run this script from

within the directory the archive extracted into. If you compiled

MySQL yourself you must run ‘make install’ first.

这个错误，是没有指明mysql的data路径导致的，可以很简单的进行解决：

vim /etc/my.cnf

在[mysqld] 后面加上路径：

basedir = /usr/local/mysql

datadir =/opt/data；

3．-bash: mysql: command not found

用mysql命令进行登陆mysql报错，原因是没有设置环境变量，需要设置，或者进入到bin目录进行登陆cd /usr/local/mysql/bin

mysql -u root

4．ERROR 1130: Host ’192.168.1.3′ is not allowed to connect to this MySQL server

用mysql远程工具链接数据库报错，这个错误原因是没有开放远程链接功能，可以在mysql里面输入如下命令进行解决：GRANT ALL PRIVILEGES ON *.* TO ’root‘@’%' IDENTIFIED BY ’password’ WITH GRANT OPTION