【运维工程师学习】Centos中MySQL替换MariaDB

1、查看已有的mysql

rpm -qa | grep mysql

• 把搜索出来的全删除

rm -rf mysql-8.0.26-1.module_el8.4.0+915+de215114.x86_64
rm -rf mysql-server-8.0.26-1.module_el8.4.0+915+de215114.x86_64
rm -rf mysql-errmsg-8.0.26-1.module_el8.4.0+915+de215114.x86_64
rm -rf mysql80-community-release-el8-5.noarch
rm -rf mysql-common-8.0.26-1.module_el8.4.0+915+de215114.x86_64

• 查看路径里那里还有mysql

whereis mysql

• 全删除

rm -rf /usr/bin/mysql
rm -rf /usr/lib64/mysql 
rm -rf /usr/share/mysql
rm -rf /usr/share/man/man1/mysql.1.gz

• 再找

find / -name mysql

• 再删

rm -rf /var/lib/selinux/targeted/active/modules/100/mysql
rm -rf /var/lib/selinux/targeted/tmp/modules/100/mysql
rm -rf /var/lib/mysql
rm -rf /var/lib/mysql/mysql
rm -rf var/log/mysql
rm -rf /var/log/mysql
rm -rf /usr/share/bash-completion/completions/mysql
rm -rf /usr/share/selinux/packages/mysql
rm -rf /usr/share/selinux/targeted/default/active/modules/100/mysql

2、MySQL官网tar包下载

MySQL官网tar包下载链接：https://dev.mysql.com/downloads/mysql/

wget https://dev.mysql.com/get/mysql-8.0.33-linux-glibc2.28-x86_64.tar.gz

3、找到下载路径解压

tar -zvxf mysql-8.0.33-linux-glibc2.28-x86_64.tar.gz

4、移动解压后的文件夹到/usr/local/mysql

mv mysql-8.0.33-linux-glibc2.28-x86_64 /usr/local/mysql

5、创建data文件夹，一般用于存放数据库文件数据

mkdir /usr/local/mysql/data

6、创建用户组

groupadd mysql;
useradd -g mysql mysql;

7、更改用户文件夹权限

chown -R mysql.mysql /usr/local/mysql/

8、生成my.cnf文件

touch /etc/my.cnf

9、编辑my.cnf

[mysql]
default-character-set=utf8
 
[mysqld]
port=3306
default_authentication_plugin=mysql_native_password
socket = /usr/local/mysql/mysql.sock
basedir=/usr/local/mysql
datadir=/usr/local/mysql/data/
character-set-server=utf8
default-storage-engine=InnoDB
collation-server=utf8_unicode_ci
init_connect='SET NAMES utf8'
innodb_buffer_pool_size=512M
innodb_flush_log_at_trx_commit=0
innodb_lock_wait_timeout=31536000
innodb_log_buffer_size=8M
innodb_log_file_size=16M
join_buffer_size=200M
key_buffer_size=400M
log-error=/usr/local/mysql/mysql.log
pid-file=/usr/local/mysql/mysql.pid
log_error_verbosity=1
max_allowed_packet=2000M
max_connections=1000
max_heap_table_size=6400M
myisam_max_sort_file_size=64M
myisam_sort_buffer_size=32M
read_buffer_size=4M
read_rnd_buffer_size=4000M
server_id=1
skip-external-locking=on
sort_buffer_size=256kb
table_open_cache=256
thread_cache_size=16
tmp_table_size=64M
wait_timeout=31536000
interactive_timeout=31536000
sql_mode="STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION"
group_concat_max_len=10240
 
[client]
port=3306
default-character-set=utf8
socket = /usr/local/mysql/mysql.sock

10、再次更改用户文件夹权限

chown -R mysql:mysql /usr/local/mysql 

11、初始化数据库

/usr/local/mysql/bin/mysqld --user=mysql --initialize --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data

如果报错 提示：

error while loading shared libraries: libaio.so.1: cannot open shared object file directory

可以执行以下命令

yum install  libaio-devel.x86_64

12、继续执行初始化数据库命令

/usr/local/mysql/bin/mysqld --user=mysql --initialize --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data

13、查看初始化密码 日志文件在 /usr/local/mysql/mysql.log

14、修改配置，挨个执行，如果报错，跳过

cp /usr/local/mysql/support-files/mysql.server /etc/init.d/mysqld
chmod +x /etc/init.d/mysqld
chmod +x /etc/rc.d/init.d/mysqld
chkconfig --add mysqld
chkconfig --list mysqld

15、修改环境变量，并重载环境变量文件

• 打开 /etc/profile 在底部添加如下命令

export PATH=$PATH:/usr/local/mysql/bin:/usr/local/mysql/lib
export PATH

• 执行

source /etc/profile

16、启动mysql

service mysql start

17、登录mysql，密码是上面的初始化密码

mysql -uroot -p;

• 如果不行进到/etc/my.cnf里 在[mysqld]下添加

skip-grant-tables

• 改完密码记得回来去掉
• 第一次登录必须要先修改密码不然会提示：

ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.

18、执行修改密码命令

flush privileges;
ALTER USER 'root'@'localhost' IDENTIFIED BY 'mysql';

• 注意退出不像MariaDB能ctrl c 退出，下面二选一

exit
quit

19、mysql启动后，连接不上，不显示3306端口

• vim /etc/my.cnf，注释掉下面两行内容，重启mysql就可以

#skip_networking
#skip-grant-tables

netstat -untlp

vim /etc/my.cnf

service mysqld restart

• 这下有3306了

20、授权远程访问

update user set host='%' where user='root'