Detailed tutorial on installing and uninstalling MySQL5.7 on Linux

MySQL5.7 is one of our commonly used Web databases. Installation and uninstallation under Linux may encounter many pitfalls. This article takes the installation and uninstallation of community version MySQL5.7 under Centos7 as an example to record the installation in detail. and the uninstallation process for your reference. If you like it, you can like it and save it, and follow us to not get lost.

operating system	MySQL
Centos7.9	MySQL5.7 Community Edition

Note: Make sure to log in to the system as root user to install

2. Detailed steps for MySQL installation

Update package

yum update -y

Check if MySQL is installed

rpm -qa | grep -i mysql

If you find that it has already been installed, please refer to Part 4 of MySQL Uninstallation.

Download Yum source configuration file

# noarch表示该软件包不依赖特定Linux发行版
wget https://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm

Install Yum source configuration file

Execute installation command

rpm -ivh mysql57-community-release-el7-11.noarch.rpm

By default, two configuration files will be generated in the /etc/yum.repos.d directory.

Install MySQL server

yum -y install mysql-community-server

The following 5 rpm packages will be installed by default

Note: The installation may fail here, prompting the exception message that Public key for mysql-community-common-5.7.43-1.el7.x86_64.rpm is not installed:

Cause of the problem: MySQL key expires

Solution: Import new key information

rpm --import https://repo.mysql.com/RPM-GPG-KEY-mysql-2022

Re-execute the installation. If the following message appears, the installation is successful.

Start the MySQL server

systemctl start mysqld

View MySQL status

systemctl status mysqld

active (running) means it has been started successfully and is running.

View MySQL version

mysql -V

Results of the

Get temporary password

grep "password" /var/log/mysqld.log

Results of the

Set root password

You can use the following two methods to set the root password when logging in for the first time:

Run security scripts (recommended for production environments)

Execute security scripts to strengthen MySQL security and set a new root password

mysql_secure_installation

Enter temporary root password

Set a new root password,The default security policy is MEDIUM, which requires at least 8 characters, including at least one uppercase and lowercase letter, one special character, and one number, otherwise Report... Failed! Error: Your password does not satisfy the current policy requirements exception.

After entering the required password, you can continue with the following configuration

Estimated strength of the password: 100 
Do you wish to continue with the password provided?(Press y|Y for Yes, any other key for No) : y
By default, a MySQL installation has an anonymous user,
allowing anyone to log into MySQL without having to have
a user account created for them. This is intended only for
testing, and to make the installation go a bit smoother.
You should remove them before moving into a production
environment.

# 移除匿名用户
Remove anonymous users? (Press y|Y for Yes, any other key for No) : y
Success.  


Normally, root should only be allowed to connect from
'localhost'. This ensures that someone cannot guess at
the root password from the network.

# 禁用远程root登录
Disallow root login remotely? (Press y|Y for Yes, any other key for No) : y
Success.

By default, MySQL comes with a database named 'test' that
anyone can access. This is also intended only for testing,
and should be removed before moving into a production
environment.

# 删除测试数据库及权限
Remove test database and access to it? (Press y|Y for Yes, any other key for No) : y
 - Dropping test database...
Success.

 - Removing privileges on test database...
Success.

Reloading the privilege tables will ensure that all changes
made so far will take effect immediately.

# 重新加载授权表
Reload privilege tables now? (Press y|Y for Yes, any other key for No) : y
Success.

All done!

Modify security policy

Execute login

mysql -uroot -p

Enter the temporary password and enter MySQL

Modify the security policy and use a simple password to log in

# 查看当前安全策略
show variables like 'validate_password%';
# 最低安全策略(0->LOW ,1->MEDIUM, 2->STRONG)
set global validate_password_policy=0; 
# 最小密码字符长度是4
set global validate_password_length=4; 
# 设置本机root密码
alter user 'root'@'localhost' identified by 'root';

After the setting is successful, enter the quit command and use the modified password to log in again. This method only takes effect temporarily and will become invalid after restarting MySQL. If it needs to take effect permanently, you need to modify /etc/my.conf and restart the MySQL service.

Set up startup

systemctl enable mysqld

Stop MySQL server

systemctl stop mysqld

3. MySQL usage examples

remote access

# 授权，all表示所有ddl和dml操作权限，*.*表示针对所有数据库所有表，%表示本机和远程主机均能访问
grant all privileges on *.* to 'root'@'%' identified by '123456' with grant option;
# 刷新权限
flush privileges;

Turn off local firewall

systemctl stop firewalld

Executed through the remote host, enter the password to access

mysql -h 192.168.5.11 -uroot -p

result

4. Detailed steps for uninstalling MySQL

Stop MySQL service

Before uninstalling MySQL, you first need to stop the MySQL service

systemctl stop mysqld

Uninstall the MySQL package

yum -y remove mysql-server mysql-client mysql-common mysql-libs

The following results indicate that the uninstallation is complete:

Delete MySQL data files and configuration files

MySQL’s data files and configuration files are usually located at /var/lib/mysql and /etc/my.cnf，执行删除命令

rm -rf /var/lib/mysql
rm -rf /etc/my.cnf

Uninstall Yum source configuration file

rpm -e mysql57-community-release-el7-11.noarch

Clean up MySQL users and groups

userdel mysql
groupdel mysql

Clean MySQL log files and temporary files

rm -rf /var/log/mysql
rm -rf /tmp/mysql*