Detailed introduction to the method of installing Mysql in CentOS7 and setting up auto-start at boot

This article mainly introduces the method of installing Mysql on CentOS 7 and setting up auto-start at boot. The editor thinks it is quite good, so I will share it with you now and give it as a reference. Let’s follow the editor and take a look.

CentOS 7 does not have a Mysql database. The default database is MariaDB (a branch of Mysql).

You can follow the steps below to install the Mysql database manually.

1. Download the rpm installation file

wget http://repo.mysql.com/mysql-community-release-el7.rpm

2. Execute the rpm installation

rpm -ivh mysql-community-release-el7.rpm

After the dependency resolution is completed, the following options will appear:

Dependencies Resolved

==============================================================================================================
 Package             Arch     Version     Repository       Size
==============================================================================================================
Installing:
 mysql-community-libs         x86_64    5.6.32-2.el7    mysql56-community     2.0 M
 replacing mariadb-libs.x86_64 1:5.5.47-1.el7_2
 mysql-community-server         x86_64    5.6.32-2.el7    mysql56-community      59 M
 Installing for dependencies:
 mysql-community-client         x86_64    5.6.32-2.el7    mysql56-community      19 M
 mysql-community-common         x86_64    5.6.32-2.el7    mysql56-community     256 k
 perl-Compress-Raw-Bzip2         x86_64    2.061-3.el7    base         32 k
 perl-Compress-Raw-Zlib         x86_64    1:2.061-4.el7   base         57 k
 perl-DBI            x86_64    1.627-4.el7    base         802 k
 perl-IO-Compress          noarch    2.061-2.el7    base         260 k
 perl-Net-Daemon           noarch    0.48-5.el7    base         51 k
 perl-PlRPC            noarch    0.2020-14.el7   base         36 k

Transaction Summary
=============================================================================================================
Install 2 Packages (+8 Dependent packages)

Total download size: 82 M
Is this ok [y/d/N]:

3. It can be seen that both server and client are selected for installation. Select y to automatically download and install.

4. After the installation is complete, start Mysql.

systemctl start mysqld.service

5. Set root password.

update user set password=password("123456") where user='root';

6. Start automatically when booting.

vim /etc/rc.local
添加service mysqld start

7. Important update:

The new rpm installation file does not have an automatic yum installation script, and you need to manually perform the yum installation.

That is, execute yum install mysql-server after step 2.

8. About self-starting

Step 6 only applies to the condition that mysqld does not start automatically.

If mysql is self-starting by default, there may be problems such as out-of-order problems with the self-starting in rc.local.

For a more reliable solution, see:

CentOS 7 program self-starting problem

1. Problem phenomenon:

After the system restarted, it was found that the mysqld service started normally, but application A that relied on the mysql database failed to start.

Checking the log shows that linking to the database failed when program A started.

2. Cause analysis:

mysqld service is started normally.

At this time, program A is manually restarted, and A is running normally.

Conclusion: When program A starts, mysqld may not start.

3. Startup sequence

The first thing that comes to mind is to adjust the startup sequence of the mysqld service so that it is higher than my program A.

However, it was found that there is no startup script for mysqld in the /etc/init.d path.

4. Solution

Mysqld installed according to the link instructions starts automatically by default.

You can cancel the self-start of mysqld, and then write a startup script to ensure that it starts before program A starts.

5. Solution

1. Check the current default starting project method of the system, it is no longer setup and the like.

systemctl list-unit-files

Execute this command to view the service startup and service status of the current system.

The result is displayed as follows:

 ...
 microcode.service       enabled 
 mysql.service        enabled 
 mysqld.service        enabled 
 NetworkManager-dispatcher.service   enabled 
 ...

2. Cancel the self-start of mysqld

systemctl disable mysqld

Execute this command and then check the service status of the current system ：

 ...
 microcode.service       enabled 
 mysqld.service        disabled
 NetworkManager-dispatcher.service   enabled 
 ...

3. Customize /etc/rc.local

First execute systemctl start mysqld

and then execute startA

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