[worthy of collection] centos7 installation MySQL complete operation command

Preface

CentOS7 The default database is mariadb,  however   A lot of them are mysql , however CentOS7 Of yum There is no default in the source mysql Of .

If you use it for the first time Linux Children's shoes can be compared with Windows Installation , The steps are the same , download -》 decompression -》 install （ Path can be specified ）, It's just Linux Is to use the command to install , Not a mouse operation , and Linux It's the file system , Everything is a document , in other words Linux No peace Windows It's the same CDE Equal drive letter ,Linux All take the file as the path . And finally , Do more with your hands

Get ready

Get ready ：VMwarecentos7 Virtual host mysql Resource path ：http://dev.mysql.com/get/mysql57-community-release-el7-7.noarch.rpm

Practice

1. uninstall   

First stop mysql process     Those that have not been installed can be skipped directly

pkill -9 mysqld

Find and list all installed MySQL rpm package

rpm -qa|grep -i mysql

Use command  yum -y remove uninstall MySQL And related packages

yum -y remove mysql-community-client-5.6.38-2.el7.x86_64
What cannot be unloaded  rpm -ev


Uninstall... In turn   Until there is no

2. download mysql Of repo Source

 /** Correct it , This source downloads the latest version   ****/

You can specify the installation directory      yum --installroot=/usr/local/mysql --releasever=/ -y install mysql-server  ） I didn't try , You don't have to worry about setting environment variables like this , Just install it and start it directly . The installation path is the default .

wget http://dev.mysql.com/get/mysql57-community-release-el7-7.noarch.rpm

After downloading, there is a mysql57-community-release-el7-7.noarch.rpm The file of , You can use the following command to see which packages the file contains ：

rpm -qpl mysql57-community-release-el7-7.noarch.rpm

install rpm package

rpm -ivh mysql57-community-release-el7-7.noarch.rpm

After installing the above package , see yum library

yum list mysql*

You can use it later yum install MySQL 了 ：

yum install mysql-community-server

MySQL installation is complete . View the installed version

mysql -V

3. Set up mysql password

1、 stop it mysql service

systemctl stop mysqld.service

2、mysql Change the configuration file to password free login .

vi /etc/my.cfg

modify

# Disabling symbolic-links is recommended to prevent assorted security risks
skip-grant-tables # Add this sentence , Now log in mysql You don't need a password
symbolic-links=0

3、 start-up  mysql  service

systemctl start mysqld.service

Change Password

set password for [email protected]=password('123456'); or update user set authentication_string=PASSWORD("123456") where user="root";

4、 With root Identity login mysql,  Enter the password directly

mysql -u root -p # Enter the command enter , You can enter the password directly .
mysql> set password for [email protected] = password('123456');
ERROR 1290 (HY000): The MySQL server is running with the --skip-grant-tables option so it cannot execute this statement
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> set password for [email protected] = password('123456'); or update user set authentication_string=PASSWORD("123456") where user="root";
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql>flush privileges; # Update the permissions
mysql>quit; # sign out

thus , The database installation and simple setup are completed

MySQL8.0

notes

： If you are installing MySQL8.0 Above version , After the installation is completed, if the login fails , You must change the initial password to log in and use normally

The basic settings are as follows ：

It is easy to enter the wrong password when logging in , So you need to get a random password first ：

grep 'temporary password' /var/log/mysqld.log // Generate random password  

mysql -uroot -p // Log in with a random password

1. Change the password corresponding to the user name

ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY ' New password '; // Change Password

Here it is directly modified to 123456 It will prompt that the password is too weak [ Must be changed to 123456, First, modify mysql8 Password rules for ]

Be careful :

Password settings must be alphanumeric and special symbols （,/’;: etc. ）, Otherwise, the setting fails .

After modification

sign out

：quit perhaps exit

If you need to connect through a remote terminal after installation , To turn on MySQL Remote access to ：

create user [email protected]'%' identified by ' Your password ';
grant all privileges on *.* to [email protected]'%' with grant option;
ALTER USER 'root'@'%' IDENTIFIED WITH mysql_native_password BY ' Your password ';
flush privileges; # Update the permissions

2. modify /etc/my.cnf  add to skip-grant-tables Skip authentication login

vim /etc/my.cnf  // modify my.cnf file
// stay [mysqld] Add... To any of the following lines "skip-grant-tables" Used to skip the password verification process , Save and exit .
mysql -uroot -p // Sign in , No password required
// Login successful ：
use mysql; // Switch to mysql library
select host,user,authentication_string from user; // You can see root User host And password ( After encryption )


3.mysql8.0 In addition to the password Field , Change to authentication_string 

update user set authentication_string = '' where user = 'root'; 
// Leave the password blank ,my.cnf Get rid of skip-grant-tables You can still log in with an empty password .
vim /etc/my.cnf 
// edit my.cnf file   Remove the previously added "skip-grant-tables", You can still log in with an empty password


You can also modify mysql The password policy for is

LOW

, Then change it to simple password or empty password to log in

see mysql Password strategy

show variables like 'validate_password%';


Explain the parameters in detail ：

validate_password.check_user_name  User name detection
validate_password.dictionary_file  Specify the file path for password verification ;
validate_password.length  Total fixed length password ;
validate_password.mixed_case_count  The whole password should contain at least large / The total number of lowercase letters ;
validate_password.number_count  The whole password must contain at least the number of Arabic numerals ;
validate_password.policy  Specify the strength verification level of the password , The default is  MEDIUM;
About  validate_password_policy  The value of ：
0/LOW： Verify length only ;
1/MEDIUM： Verify the length 、 Numbers 、 Case write 、 Special characters ;
2/STRONG： Verify the length 、 Numbers 、 Case write 、 Special characters 、 Dictionary file ;

validate_password.special_char_count  The whole password should contain at least the number of special characters
set global validate_password.policy=LOW; // Set password strength to LOW

After the policy is modified , Change Password ：
alter user 'root'@'localhost' identified by 'root'; // Change the password to root, It indicates that the modification is successful

The above is MySQL8.0 Simple setup and precautions after installation , Let's practice ！