MySQL Data base Installation

To install MySQL on a CentOS 7 system, follow these steps:

[root@server ~]# wget https://dev.mysql.com/get/mysql57-community-release-el7-9.noarch.rpm
[root@server ~]# yum -y install mysql57-community-release-el7-9.noarch.rpm
[root@server ~]# cd /etc/yum.repos.d/
[root@server ~]# yum -y install mysql-server

Starting the MySQL Service

After installation, start the MySQL service with the following command:

[root@server ~]# systemctl start mysqld

Retireving the Initial Root Password

The MySQL installation generates a temporary root password. You can find it in the log file:

[root@server ~]# grep 'temporary password' /var/log/mysqld.log

# The root@localhost: *** shown in the output is the initial login password

Connecting to MySQL

Use the following command to connect to the MySQL server with the root account:

[root@server ~]# mysql -u root -p
[root@server ~]# Enter password:

Setting a New Password

Once connected to MySQL, set a new password for the root user:

mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD('your_new_password');

Checking Password Policy Settings

Verify the current password policy configuration:

mysql> SHOW VARIABLES LIKE 'validate_password%';

Modifying Password Policy

If needed, adjust the password policy to be less restrictive:

mysql> SET GLOBAL validate_password_policy = LOW;

Setting Minimum Password Length

Configure the minimum password length to 6 characters:

mysql> SET GLOBAL validate_password_length = 6;

Applying New Password

Set a new password that meets the policy requirements:

mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD('secure_password');

Enabling Remote Access

To allow remote connecsions to the MySQL server:

mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'secure_password' WITH GRANT OPTION;
mysql> FLUSH PRIVILEGES;

Complete MySQL Uninstallation on CentOS 7

Identifying MySQL-related RPM Packages

First, list all MySQL-related packages installed on the system:

[root@server ~]# rpm -qa | grep -i mysql
mysql57-community-release-el7-9.noarch
mysql-community-client-5.7.32-1.el7.x86_64
mysql-community-libs-5.7.32-1.el7.x86_64
mysql-community-libs-compat-5.7.32-1.el7.x86_64
mysql-community-common-5.7.32-1.el7.x86_64
mysql-community-server-5.7.32-1.el7.x86_64

Removing MySQL Packages

Uninstall all identified MySQL packages using yum:

[root@server ~]# yum remove mysql57-community-release-el7-9.noarch
[root@server ~]# yum remove mysql-community-client-5.7.32-1.el7.x86_64
[root@server ~]# yum remove mysql-community-libs-5.7.32-1.el7.x86_64
[root@server ~]# yum remove mysql-community-libs-compat-5.7.32-1.el7.x86_64
[root@server ~]# yum remove mysql-community-common-5.7.32-1.el7.x86_64
[root@server ~]# yum remove mysql-community-server-5.7.32-1.el7.x86_64

Finding MySQL-related Directories

Locate any remaining MySQL directories on the system:

[root@server ~]# find / -name mysql
/etc/selinux/targeted/active/modules/100/mysql
/var/lib/mysql
/var/lib/mysql/mysql
/usr/share/mysql

Removing Residual Directories

Delete all remaining MySQL-related directories:

[root@server ~]# rm -rf /etc/selinux/targeted/active/modules/100/mysql
[root@server ~]# rm -rf /var/lib/mysql
[root@server ~]# rm -rf /var/lib/mysql/mysql
[root@server ~]# rm -rf /usr/share/mysql

Removing MySQL Log File

Delete the MySQL log file to prevent issues with future installations:

[root@server ~]# rm -rf /var/log/mysqld.log
# If this file is not removed, it may cause problems with new MySQL installations