centos7下安装mysql

下载并安装MySQL官方的 Yum Repository
这里安装mysql-5.7

# wget -i -c http://dev.mysql.com/get/mysql57-community-release-el7-10.noarch.rpm
# yum -y install mysql57-community-release-el7-10.noarch.rpm
# yum -y install mysql-community-server

网速不好的话下载安装过程较慢，要等待一段时间

[root@localhost ~]# yum install mysql-community-server --nogpgcheck
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
 * base: mirrors.huaweicloud.com
 * epel: mirrors.aliyun.com
 * extras: mirrors.nwsuaf.edu.cn
 * updates: mirrors.nwsuaf.edu.cn
mysql-connectors-community                                                                                  | 2.5 kB  00:00:00     
mysql-tools-community                                                                                       | 2.5 kB  00:00:00     
mysql57-community                                                                                           | 2.5 kB  00:00:00     
(1/3): mysql57-community/x86_64/primary_db                                                                  | 144 kB  00:00:02     
(2/3): mysql-connectors-community/x86_64/primary_db                                                         |  20 kB  00:00:05     
(3/3): mysql-tools-community/x86_64/primary_db                                                              |  41 kB  00:00:05     
Resolving Dependencies
--> Running transaction check
---> Package mysql-community-server.x86_64 0:5.7.22-1.el7 will be installed
--> Processing Dependency: mysql-community-common(x86-64) = 5.7.22-1.el7 for package: mysql-community-server-5.7.22-1.el7.x86_64
--> Processing Dependency: mysql-community-client(x86-64) >= 5.7.9 for package: mysql-community-server-5.7.22-1.el7.x86_64
--> Running transaction check
---> Package mysql-community-client.x86_64 0:5.7.22-1.el7 will be installed
--> Processing Dependency: mysql-community-libs(x86-64) >= 5.7.9 for package: mysql-community-client-5.7.22-1.el7.x86_64
---> Package mysql-community-common.x86_64 0:5.7.22-1.el7 will be installed
--> Running transaction check
---> Package mariadb-libs.x86_64 1:5.5.56-2.el7 will be obsoleted
--> Processing Dependency: libmysqlclient.so.18()(64bit) for package: 2:postfix-2.10.1-6.el7.x86_64
--> Processing Dependency: libmysqlclient.so.18(libmysqlclient_18)(64bit) for package: 2:postfix-2.10.1-6.el7.x86_64
---> Package mysql-community-libs.x86_64 0:5.7.22-1.el7 will be obsoleting
--> Running transaction check
---> Package mysql-community-libs-compat.x86_64 0:5.7.22-1.el7 will be obsoleting
--> Finished Dependency Resolution

Dependencies Resolved

===================================================================================================================================
 Package                                   Arch                 Version                      Repository                       Size
===================================================================================================================================
Installing:
 mysql-community-libs                      x86_64               5.7.22-1.el7                 mysql57-community               2.1 M
     replacing  mariadb-libs.x86_64 1:5.5.56-2.el7
 mysql-community-libs-compat               x86_64               5.7.22-1.el7                 mysql57-community               2.0 M
     replacing  mariadb-libs.x86_64 1:5.5.56-2.el7
 mysql-community-server                    x86_64               5.7.22-1.el7                 mysql57-community               165 M
Installing for dependencies:
 mysql-community-client                    x86_64               5.7.22-1.el7                 mysql57-community                24 M
 mysql-community-common                    x86_64               5.7.22-1.el7                 mysql57-community               274 k

Transaction Summary
===================================================================================================================================
Install  3 Packages (+2 Dependent packages)

Total download size: 193 M
Is this ok [y/d/N]: y
Downloading packages:
warning: /var/cache/yum/x86_64/7/mysql57-community/packages/mysql-community-common-5.7.22-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Public key for mysql-community-common-5.7.22-1.el7.x86_64.rpm is not installed
(1/5): mysql-community-common-5.7.22-1.el7.x86_64.rpm                                                       | 274 kB  00:00:01     
(2/5): mysql-community-libs-5.7.22-1.el7.x86_64.rpm                                                         | 2.1 MB  00:00:02     
(3/5): mysql-community-libs-compat-5.7.22-1.el7.x86_64.rpm                                                  | 2.0 MB  00:00:06     
(4/5): mysql-community-client-5.7.22-1.el7.x86_64.rpm                                                       |  24 MB  00:01:56     
(5/5): mysql-community-server-5.7.22-1.el7.x86_64.rpm                                                       | 165 MB  00:17:07     
-----------------------------------------------------------------------------------------------------------------------------------
Total                                                                                              191 kB/s | 193 MB  00:17:17     
Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
Importing GPG key 0x5072E1F5:
 Userid     : "MySQL Release Engineering <mysql-build@oss.oracle.com>"
 Fingerprint: a4a9 4068 76fc bd3c 4567 70c8 8c71 8d3b 5072 e1f5
 Package    : mysql57-community-release-el7-10.noarch (installed)
 From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
Is this ok [y/N]: y
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : mysql-community-common-5.7.22-1.el7.x86_64                                                                      1/6 
  Installing : mysql-community-libs-5.7.22-1.el7.x86_64                                                                        2/6 
  Installing : mysql-community-client-5.7.22-1.el7.x86_64                                                                      3/6 
  Installing : mysql-community-server-5.7.22-1.el7.x86_64                                                                      4/6 
  Installing : mysql-community-libs-compat-5.7.22-1.el7.x86_64                                                                 5/6 
  Erasing    : 1:mariadb-libs-5.5.56-2.el7.x86_64                                                                              6/6 
  Verifying  : mysql-community-libs-compat-5.7.22-1.el7.x86_64                                                                 1/6 
  Verifying  : mysql-community-common-5.7.22-1.el7.x86_64                                                                      2/6 
  Verifying  : mysql-community-server-5.7.22-1.el7.x86_64                                                                      3/6 
  Verifying  : mysql-community-client-5.7.22-1.el7.x86_64                                                                      4/6 
  Verifying  : mysql-community-libs-5.7.22-1.el7.x86_64                                                                        5/6 
  Verifying  : 1:mariadb-libs-5.5.56-2.el7.x86_64                                                                              6/6 

Installed:
  mysql-community-libs.x86_64 0:5.7.22-1.el7                    mysql-community-libs-compat.x86_64 0:5.7.22-1.el7                 
  mysql-community-server.x86_64 0:5.7.22-1.el7                 

Dependency Installed:
  mysql-community-client.x86_64 0:5.7.22-1.el7                     mysql-community-common.x86_64 0:5.7.22-1.el7                    

Replaced:
  mariadb-libs.x86_64 1:5.5.56-2.el7                                                                                               

Complete!

至此已安装完毕
接下来启动mysql

[root@localhost ~]# systemctl restart mysqld

启动成功之后进入mysql
通过# grep "password" /var/log/mysqld.log 查看初始密码
输入初始密码，此时不能做任何事情，因为MySQL默认必须修改密码之后才能操作数据库

mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'your password';

可能会提示ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
提示是密码不安全过于简单
此时可通过执行

mysql> set global validate_password_policy=0;
mysql> set global validate_password_length=1;

4、MySQL 8.0 调整密码验证规则：

mysql> set global validate_password.policy=0;
mysql> set global validate_password.length=1;

修改mysql密码命名规则就可以设置1234这类密码了
但是出于安全性考虑，生产环境mysql不要执行此语句，设置一个安全性较强的密码。
可以通过mysql> SHOW VARIABLES LIKE 'validate_password%';查看密码规则。
由于安装了Yum Repository，以后每次yum操作都会自动更新，需要把这个卸载掉：

# yum -y remove mysql57-community-release-el7-10.noarch

创建远程连接用户

CREATE USER 'root'@'%' IDENTIFIED BY 'password';
#授权
grant all privileges on *.* to 'root'@'%';
flush privileges;