MySQL 8.0.11安装配置

官网地址：https://dev.mysql.com/downloads/mysql/

我这里是RHEL6.5的系统，因此选择RedHat 6 x86,64bit操作系统---下载第一个RPM Bundle即可--mysql-8.0.11-1.el6.x86_64.rpm-bundle.tar。

目前MySQL8.0.11社区版提供了多种多样的安装方式，你也可以通过下载Linux Generic安装包mysql-8.0.11-linux-glibc2.12-x86_64.tar.gz来安装，这种安装方式无需考虑包兼容性，本文只描述rpm安装方式。

wget https://cdn.mysql.com//Downloads/MySQL-8.0/mysql-8.0.11-1.el6.x86_64.rpm-bundle.tar

如果上述链接失效，一般是因为官网已经更新了新版本，找到最新版本的版本号修改下载即可。

一、mysql-8.0.11-1.el6.x86_64.rpm-bundle.tar解压后有如下7个文件：

-rw-r--r-- 1 root root  28987588 Apr  9 01:06 mysql-community-client-8.0.11-1.el6.x86_64.rpm
-rw-r--r-- 1 root root    672184 Apr  9 01:06 mysql-community-common-8.0.11-1.el6.x86_64.rpm
-rw-r--r-- 1 root root   4443296 Apr  9 01:06 mysql-community-devel-8.0.11-1.el6.x86_64.rpm
-rw-r--r-- 1 root root   2579460 Apr  9 01:06 mysql-community-libs-8.0.11-1.el6.x86_64.rpm
-rw-r--r-- 1 root root   1902676 Apr  9 01:06 mysql-community-libs-compat-8.0.11-1.el6.x86_64.rpm
-rw-r--r-- 1 root root 395918848 Apr  9 01:07 mysql-community-server-8.0.11-1.el6.x86_64.rpm
-rw-r--r-- 1 root root  49092596 Apr  9 01:07 mysql-community-test-8.0.11-1.el6.x86_64.rpm

然后创建mysql用户：

useradd mysql
passwd mysql

二、安装顺序为：（强烈建议装之前先把之前的或自带的mysql相关包全部卸载，rpm -e --nodeps <包名>即可）

rpm -ivh mysql-community-common-8.0.11-1.el6.x86_64.rpm \
mysql-community-libs-8.0.11-1.el6.x86_64.rpm \
mysql-community-libs-compat-8.0.11-1.el6.x86_64.rpm \
mysql-community-client-8.0.11-1.el6.x86_64.rpm \
mysql-community-server-8.0.11-1.el6.x86_64.rpm \
mysql-community-devel-8.0.11-1.el6.x86_64.rpm

三、安装完毕后相关信息如下：

[root@python ~]# mysql -V
mysql  Ver 8.0.11 for Linux on x86_64 (MySQL Community Server - GPL)
[root@python ~]# ll /etc/init.d/mysqld 
-rwxr-xr-x 1 root root 7166 Apr  8 16:21 /etc/init.d/mysqld
[root@python ~]# ll /etc/my.cnf --配置文件位置
-rw-r--r-- 1 root root 1188 Apr  8 16:21 /etc/my.cnf

默认的datadir是在/var/lib/mysql/，可以通过修改my.cnf修改，启动命令如下：

[root@python ~]# service mysqld start
Initializing MySQL database:                               [  OK  ]
Starting mysqld:                                           [  OK  ]

四、使用默认密码登录MySQL

在安装完后，/var/log/mysqld.log里应该含有临时的root密码，可以直接登录，你可以将此root密码更改为自己更熟悉的密码。

mysql> alter user root@'localhost' identified by 'mysql';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements

这里存在密码复杂度要求（在Windows平台使用msi安装mysql时，则有自主选择密码认证方式的步骤，可以比较方便的进行设置。）：

mysql> show variables like '%pass%';
+----------------------------------------------+-----------------+
| Variable_name                                | Value           |
+----------------------------------------------+-----------------+
| caching_sha2_password_auto_generate_rsa_keys | ON              |
| caching_sha2_password_private_key_path       | private_key.pem |
| caching_sha2_password_public_key_path        | public_key.pem  |
| default_password_lifetime                    | 0               |
| disconnect_on_expired_password               | ON              |
| mysql_native_password_proxy_users            | OFF             |
| password_history                             | 0               |
| password_reuse_interval                      | 0               |
| report_password                              |                 |
| sha256_password_auto_generate_rsa_keys       | ON              |
| sha256_password_private_key_path             | private_key.pem |
| sha256_password_proxy_users                  | OFF             |
| sha256_password_public_key_path              | public_key.pem  |
| validate_password.check_user_name            | ON              |
| validate_password.dictionary_file            |                 |
| validate_password.length                     | 8               |
| validate_password.mixed_case_count           | 1               |
| validate_password.number_count               | 1               |
| validate_password.policy                     | MEDIUM          |
| validate_password.special_char_count         | 1               |
+----------------------------------------------+-----------------+

查看官网https://dev.mysql.com/doc/refman/8.0/en/validate-password-options-variables.html#sysvar_validate_password.policy

发现此值有3个，如下所示：

于是设置为0，然后将validate_password.length设置为4，表示最少需要4字符。之所以设置为4是因为这个参数的值不能小于如下公式的计算结果：

validate_password.number_count
+ validate_password.special_char_count
+ (2 * validate_password.mixed_case_count)

五、建一个测试用户leo，尝试远程连接下吧：

$ mysql -uleo -pmysql -h192.168.1.193
mysql: [Warning] Using a password on the command line interface can be insecure.
ERROR 2059 (HY000): Authentication plugin 'caching_sha2_password' cannot be loaded: /usr/lib/mysql/plugin/caching_sha2_password.so: cannot open shared object file: No such file or directory

我这5.7的mysql工具都连不上，这就尴尬了，查看认证相关参数：

mysql> show variables like '%auth%';
+-------------------------------+-----------------------+
| Variable_name                 | Value                 |
+-------------------------------+-----------------------+
| default_authentication_plugin | caching_sha2_password |
+-------------------------------+-----------------------+
1 row in set (0.02 sec)

查看官网发现此值的取值如下：

官网还说此值影响create user不显式指定auth plugin时密码的默认加密算法，这意味着低版本的mysql工具基本连不上8.0，简单起见我们直接使用以前的加密算法。

mysql> select user,host,plugin from mysql.user;
+------------------+-----------+-----------------------+
| user             | host      | plugin                |
+------------------+-----------+-----------------------+
| leo              | %         | caching_sha2_password |
| mysql.infoschema | localhost | mysql_native_password |
| mysql.session    | localhost | mysql_native_password |
| mysql.sys        | localhost | mysql_native_password |
| root             | localhost | caching_sha2_password |
+------------------+-----------+-----------------------+

在my.cnf里添加：default_authentication_plugin=mysql_native_password，然后service mysqld restart重启服务，以下只演示leo用户的创建：

mysql> drop user leo;
Query OK, 0 rows affected (0.10 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> create user leo identified by 'mysql';
Query OK, 0 rows affected (0.02 sec)
mysql> grant all on *.* to leo;
Query OK, 0 rows affected (0.08 sec)

$mysql -V
mysql  Ver 14.14 Distrib 5.7.20, for Linux (x86_64) using  EditLine wrapper
$ mysql -uleo -pmysql -h192.168.1.193
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 16
Server version: 8.0.11 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
owners.

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

mysql> 

至此远程连接正常。

如果你想使用8.0的mysql客户端连接8.0以前的mysql server，那么就需要在mysql的命令行后添加--default-auth，示例：

mysql -hxxx -Pxxx -uxxx -pxxx --default-auth="mysql_native_password"

或者在mysql配置文件的[mysql]部分加上default_auth=mysql_native_password.