在我的 ubuntu 16.04 服务器中，我尝试通过以下命令安装 mysql
sudo apt-get install mysql-server
每次它都卡在消息中时：
update-alternatives: using /etc/mysql/mysql.cnf to provide /etc/mysql/my.cnf (my.cnf) in auto mode
Renaming removed key_buffer and myisam-recover options (if present)
Checking if update is needed.
This installation of MySQL is already upgraded to 5.7.16, use --force if you still need to run mysql_upgrade
我必须按Ctrl+z才能停止它。我已经检查了日志文件/var/log/mysql/error.log，它的最后 10 行显示了这个结果：
2017-01-18T09:07:30.329930Z 0 [Note] InnoDB: Buffer pool(s) load completed at 170118 9:07:30
2017-01-18T09:07:30.335086Z 0 [Warning] Failed to set up SSL because …