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，但是并未发现针对Linux Generic安装包包含的mysql_secure_installation的安装说明。
MySQL官网地址：https://dev.mysql.com/downloads/mysql/
因此这里使用推荐的RPM安装：
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：(建议装之前先把之前的mysql相关包全部卸载，rpm -e --nodeps 即可)
[root@Python ~]# rpm -ivh mysql-community-common-8.0.11-1.el6.x86_64.rpm
warning: mysql-community-common-8.0.11-1.el6.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ########################################### [100%]
1:mysql-community-common ########################################### [100%]
[root@python ~]# rpm -ivh mysql-community-libs-8.0.11-1.el6.x86_64.rpm
warning: mysql-community-libs-8.0.11-1.el6.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ########################################### [100%]
1:mysql-community-libs ########################################### [100%]
[root@python ~]# rpm -ivh mysql-community-libs-compat-8.0.11-1.el6.x86_64.rpm
warning: mysql-community-libs-compat-8.0.11-1.el6.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ########################################### [100%]
file /usr/lib64/mysql/libmysqlclient.so.16.0.0 from install of mysql-community-libs-compat-8.0.11-1.el6.x86_64 conflicts with file from package mysql-libs-5.1.73-8.0.1.el6_8.x86_64
file /usr/lib64/mysql/libmysqlclient_r.so.16.0.0 from install of mysql-community-libs-compat-8.0.11-1.el6.x86_64 conflicts with file from package mysql-libs-5.1.73-8.0.1.el6_8.x86_64
[root@python ~]# rpm -e --nodeps mysql-libs-5.1.73-8.0.1.el6_8.x86_64
[root@python ~]# rpm -ivh mysql-community-libs-compat-8.0.11-1.el6.x86_64.rpm
warning: mysql-community-libs-compat-8.0.11-1.el6.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ########################################### [100%]
1:mysql-community-libs-co########################################### [100%]
[root@python ~]# rpm -ivh mysql-community-server-8.0.11-1.el6.x86_64.rpm
warning: mysql-community-server-8.0.11-1.el6.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
error: Failed dependencies:
mysql-community-client(x86-64) >= 8.0.0 is needed by mysql-community-server-8.0.11-1.el6.x86_64
[root@python ~]# rpm -ivh mysql-community-client-8.0.11-1.el6.x86_64.rpm
warning: mysql-community-client-8.0.11-1.el6.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ########################################### [100%]
1:mysql-community-client ########################################### [100%]
[root@python ~]# rpm -ivh mysql-community-server-8.0.11-1.el6.x86_64.rpm
warning: mysql-community-server-8.0.11-1.el6.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ########################################### [100%]
1:mysql-community-server ########################################### [100%]
[root@python ~]# rpm -ivh mysql-community-devel-8.0.11-1.el6.x86_64.rpm
warning: mysql-community-devel-8.0.11-1.el6.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ########################################### [100%]
1:mysql-community-devel ########################################### [100%]
^[[A[root@python ~]# rpm -ivh mysql-community-test-8.0.11-1.el6.x86_64.rpm
warning: mysql-community-test-8.0.11-1.el6.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
error: Failed dependencies:
perl(JSON) is needed by mysql-community-test-8.0.11-1.el6.x86_64
--懒的去装perl了，因此测试套件就不装了。
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、发现没密码不能登录，于是添加skip-grant-tables到my.cnf，重启进去重置密码
mysql> alter user root@'localhost' identified by 'mysql';
ERROR 1290 (HY000): The MySQL server is running with the --skip-grant-tables option so it cannot execute this statement
mysql> exit
Bye
居然不能改。。。于是：
mysql> delete from mysql.user where user='root';
Query OK, 1 row affected (0.10 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> create user root@'localhost' identified by 'mysql';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
还是不能改，查看密码复杂度要求：
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)
于是继续创建用户，MySQL8.0取消了直接grant创建用户的语法，只能先create user再grant，因此创建root如下：
mysql> create user root@'localhost' identified by 'mysql';
ERROR 1396 (HY000): Operation CREATE USER failed for 'root'@'localhost'
mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)
mysql> create user root@'localhost' identified by 'mysql';
ERROR 1396 (HY000): Operation CREATE USER failed for 'root'@'localhost'
尼玛...什么玩意儿？
于是去逛了一圈stackoverflow,都说这是一个BUG，于是操作如下：
mysql> drop user root@'localhost'; --是的没错，虽然没有root@'localhost'用户，但你还是要删一遍。
Query OK, 0 rows affected (0.05 sec)
mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.01 sec)
mysql> create user root@'localhost' identified by 'mysql';
Query OK, 0 rows affected (0.03 sec)
mysql> grant all on *.* to root@'localhost' with grant option;
Query OK, 0 rows affected (0.03 sec)
终于改完密码了...去掉参数文件的skip-grant-tables参数，service mysqld restart重启服务。
五、终于设置好密码了，建一个测试用户leo，然后尝试远程连接下吧：
$ 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，卧槽...那岂不是说我之前创建的leo用户使用的是默认的caching_sha2_password认证，查看一下：
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 |
+------------------+-----------+-----------------------+
完了，全TM完了......
显然不能直接update plugin，因为这可能导致加密的密码无法被正确解密，你所有的密码都会变异，因此除root@'localhost'外全部删掉重建。
首先需要在my.cnf里添加：default_authentication_plugin=mysql_native_password，然后service mysqld restart重启服务：
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。
