解决 MySQL 8.0 启动时的错误“CA certificate ca.pem is self signed”

cat >> /etc/my.cnf <<EOF
[client]
# SSL Settings
ssl-ca=/var/lib/mysql/ca.pem
ssl-cert=/var/lib/mysql/client-cert.pem
ssl-key=/var/lib/mysql/client-key.pem

[mysqld]
# SSL Settings
ssl-ca=/var/lib/mysql/ca.pem
ssl-cert=/var/lib/mysql/server-cert.pem
ssl-key=/var/lib/mysql/server-key.pem
EOF

重启 MySQL 服务。

检验是否生效

1. 登录进 MySQL Shell

   mysql -uroot -p
   # 输入密码

2. 执行下面的 SQL 语句

   SHOW VARIABLES LIKE '%ssl%';

   于是得到以下的结果：

   mysql> SHOW VARIABLES LIKE '%ssl%';
   +--------------------+--------------------------------+
   | Variable_name      | Value                          |
   +--------------------+--------------------------------+
   | have_openssl       | YES                            |
   | have_ssl           | YES                            |
   | mysqlx_ssl_ca      |                                |
   | mysqlx_ssl_capath  |                                |
   | mysqlx_ssl_cert    |                                |
   | mysqlx_ssl_cipher  |                                |
   | mysqlx_ssl_crl     |                                |
   | mysqlx_ssl_crlpath |                                |
   | mysqlx_ssl_key     |                                |
   | ssl_ca             | /var/lib/mysql/ca.pem          |
   | ssl_capath         |                                |
   | ssl_cert           | /var/lib/mysql/server-cert.pem |
   | ssl_cipher         |                                |
   | ssl_crl            |                                |
   | ssl_crlpath        |                                |
   | ssl_fips_mode      | OFF                            |
   | ssl_key            | /var/lib/mysql/server-key.pem  |
   +--------------------+--------------------------------+
   17 rows in set (0.01 sec)
   
   mysql>

   执行语句：

   SHOW SESSION STATUS LIKE '%Ssl_version%';

   执行结果：

   mysql> SHOW SESSION STATUS LIKE '%Ssl_version%';
   +--------------------+---------+
   | Variable_name      | Value   |
   +--------------------+---------+
   | Mysqlx_ssl_version |         |
   | Ssl_version        | TLSv1.3 |
   +--------------------+---------+
   2 rows in set (0.00 sec)
   mysql>

解决方案完成任务。

感谢：

https://stackoverflow.com/questions/34342300/problems-setting-up-ssl-connections-for-mysql-on-ubuntu-14-04