Install Mysql under centos7

Download Mysql

I use 64-bit MySQL 5.7.20 to execute the following commands


Encounter problems

1,wget commond not found

If you sign up for wget commond not found ation, you have not installed wget configuration for centos.
This command needs to be executed at this time.

yum -y install wget

Wait for your centos to install the wget configuration. When you see this, the installation is successful.

2,404 not found

Unexpectedly, the wget command adds http://leading to 404 in front of your link. At this time, let's modify it (remove the HTTP protocol header) and execute the following command to connect and download successfully.


At this time, I was wondering why not use the xshell to connect my virtual machine. xshell is much more comfortable to use. The following operations are all done in the xshell.

Decompression Mysql

Because I'm downloading the installation package in the / root directory, I now execute the following command to copy it to / usr/local (don't copy it blindly, you have to follow your own actual directory).

cp mysql-5.7.20-linux-glibc2.12-x86_64.tar.gz ../usr/local

Then enter the / usr/local directory to decompress and get the folder mysql-5.7.20-linux-glibc2.12-x86_64.
Rename it mysql with the following specific commands

cd ../usr/local
tar -zxvf mysql-5.7.20-linux-glibc2.12-x86_64.tar.gz
mv mysql-5.7.20-linux-glibc2.12-x86_64 mysql 

Install Mysql

1. New User Groups and Users

Execute the following commands

cd mysql
groupadd mysql
useradd -r -g mysql mysql

Explain it.

The useradd-r parameter indicates that the mysql user is a system user and cannot be used to log in to the system.
The useradd-g parameter indicates that the mysql user is added to the mysql user group.

2. Create directories and authorize

mkdir data mysql-files
chown -R mysql .
chgrp -R mysql .

3. Initialization of Mysql

Execute the following commands

bin/mysqld --initialize --user=mysql

Error reporting

If you make the following mistake, it means that you lack the installation packages libaio and libaio-devel.

bin/mysqld: error while loading shared libraries: cannot open shared object file: No such file or directory


At this point you need to execute the following command to install

yum install libaio*

After installation, execute again

bin/mysqld --initialize --user=mysql

Error reporting

If you report the following mistake

2017-12-17T13:30:25.171173Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2017-12-17T13:30:25.173048Z 0 [ERROR] --initialize specified but the data directory has files in it. Aborting.

Cause explanation

When mysql is initialized, it detects whether the data directory exists.
If it does not exist, mysql will create it.
If it exists and there is data in this directory, mysql will report an error and terminate initialization.


Delete or rename the data directory. If the data is important, rename it and import it later. My directory is in / var/lib/mysql./
Delete directly

rm -rf /var/lib/mysql

Execute the order again

bin/mysqld --initialize --user=mysql

It's not easy to succeed at last. I hope you can initialize it quickly and successfully.

4. Mysql Temporary Key

After success, the following will appear

The temporary password generated by mysql is root@localhost:the following string VBsA6h.:Y5Iq

2017-12-17T13:32:39.695323Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2017-12-17T13:32:41.207504Z 0 [Warning] InnoDB: New log files created, LSN=45790
2017-12-17T13:32:41.572597Z 0 [Warning] InnoDB: Creating foreign key constraint system tables.
2017-12-17T13:32:41.648447Z 0 [Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: c1bd1420-e32e-11e7-9ff3-000c29fcc852.
2017-12-17T13:32:41.650409Z 0 [Warning] Gtid table is not ready to be used. Table 'mysql.gtid_executed' cannot be opened.
2017-12-17T13:32:41.652045Z 1 [Note] A temporary password is generated for root@localhost: VBsA6h.:Y5Iq

5. Generating RSA Private Key

Execute the following commands


6. Granting Read and Write Rights

Execute the following commands

chown -R root .
chown -R mysql data mysql-files

7. Add Mysql startup script to system service

Execute the following commands

cp support-files/mysql.server /etc/init.d/mysql.server

Start the Mysql service

Finally, it's exciting time to exit to the root directory / below
Executive order

service mysql.server start


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

If you still report this mistake

Starting MySQL.2017-12-17T13:59:15.498616Z mysqld_safe error: log-error set to '/var/log/mariadb/mariadb.log', however file don't exists. Create writable for user 'mysql'.
 ERROR! The server quit without updating PID file (/var/lib/mysql/

You need to grant read and write permission to the day directory

[root@chenyu /]# mkdir /var/log/mariadb
[root@chenyu /]# touch /var/log/mariadb/mariadb.log
[root@chenyu /]# chowm -R mysql:mysql /var/log/mariadb
-bash: chowm: No command found
[root@chenyu /]# chown -R mysql:mysql /var/log/mariadb

I made an awkward mistake here. Don't learn.

Login Mysql

The password is the password of step 4 above, but the following error is reported.

[root@chenyu /]# /usr/local/mysql/bin/mysql -uroot -p
Enter password: 
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)
[root@chenyu /]# 

Solution modification/etc/my.cnf
I commented it out, then added a line / tmp/mysql.sock to save and restart Mysql service after exiting. See below for the specific operation command.

[root@chenyu /]# more /etc/my.cnf | grep sock
[root@chenyu /]# vi /etc/my.cnf
[root@chenyu /]# service mysql.server start
[root@chenyu /]# vi /etc/my.cnf
[root@chenyu /]# service mysql.server start
Starting MySQL.. SUCCESS! 
[root@chenyu /]# 

The modified / etc/my.cnf looks like the following


Log in again

Password or Step 4 Password

/usr/local/mysql/bin/mysql -uroot -p

Setting Mysql password

mysql> set password=password('123456');

Refresh permission and exit. See below for details.

mysql> set password=password('123456');
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)

mysql> exit;
[root@chenyu /]# 

Log in again with a new password

[root@chenyu /]# /usr/local/mysql/bin/mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.7.20 MySQL Community Server (GPL)

Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.


So far, the entire installation of Mysql has been completed.

Keywords: MySQL MariaDB Linux socket

Added by gladius on Fri, 17 May 2019 11:18:19 +0300