MySQL installation

Installation package download address ： https://downloads.mysql.com/archives/community/

Check to see if there are already installed MySQL

Check whether the system is installed mysql：

rpm -qa | grep mysql

If so, force uninstall ：

rpm -e --nodeps $(rpm -qa | grep mysql)

Or use

find / -name mysql
#  perhaps  whereis mysql  Inquire about MySQL Related documents 
#  Use after discovery rm -rf Delete 

MySQL install

Upload to the server and extract the file , Must be MySQL Transferred to /usr/local/mysql/ Under the table of contents , Otherwise start will report an error

tar -xvf mysql-5.7.37-linux-glibc2.12-x86_64.tar.gz
mv mysql-5.7.37-linux-glibc2.12-x86_64/* /usr/local/mysql/ #  modify MySQL Catalog , If /usr/local/mysql/ New if it doesn't exist 

Build users and groups

groupadd mysql
useradd -r -g mysql -s /bin/false mysql

Create related directories

mkdir -p /data/mysql
chown -R mysql:mysql /data  #  to MySQL Authorize this directory permission 
chown -R mysql:mysql /usr/local/mysql/
chmod 755 /data
``
##  Configure environment variables 
 To configure root User environment variable 

```sql
cat <<EOF>> /root/.bash_profile  # <<EOF>> Identification input EOF End editing 

Enter... In the editable state of the file

> export PATH=\$PATH:/usr/local/mysql/bin
> EOF

Effective environment variables

source /root/.bash_profile

Compile and initialize

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

Copy the password after execution

To configure my.cnf

stay MySQL Catalog cd /soft/mysql-5.7.37 establish my.cnf

[mysqld] 
user=mysql
datadir=/data/mysql
basedir=/usr/local/mysql
pid-file=/data/mysql/mysql.pid
port = 3306
sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES
symbolic-links=0
max_connections=400
innodb_file_per_table=1
lower_case_table_names=1
character_set_server=utf8mb4
socket=/data/mysql/mysql.sock

[mysqld] It can't be less , This is the file header
socket and pid-file It is best to assign and give mysql The user gives authority
Start the service

/usr/local/mysql/support-files/mysql.server start

This indicates that the startup was successful

add to mysql Soft connect and restart mysql service

ln -s /usr/local/mysql/support-files/mysql.server /etc/init.d/mysql 
ln -s /usr/local/mysql/bin/mysql /usr/bin/mysql
service mysql restart

Change Password

Sign in

mysql -u root -p  # Enter the password after prompting for it 

set password for root@localhost = password('123456'); # 123456 For the modified password 

Modify any ip All accessible

use mysql;
update user set user.Host='%' where user.User='root';
flush privileges;

Problems encountered during installation

1. At first I didn't put MySQL The installation directory is set to /usr/local/mysql Initiate error reporting
2. No settings pid File startup error
3. There was no... When I logged in mysql.sock File error
4. And the startup times ignores my.cnf file , as a result of my.cnf Permission is 777, Need to change to 655 Will not be ignored
   After creating files for the above categories , And then to mysql User authorization is sufficient , adopt chown -R mysql:mysql File path
   chmod 755 File path