出现如下错误
2 not fully installed or removed. Need to get 0 B/10.0 kB of archives. After this operation, 111 kB of additional disk space will be used. Selecting previously unselected package mysql-client. (Reading database ... 220054 files and directories currently installed.) Preparing to unpack .../mysql-client_5.7.30-0ubuntu0.16.04.1_all.deb ... Unpacking mysql-client (5.7.30-0ubuntu0.16.04.1) ... Setting up mysql-server-5.7 (5.7.30-0ubuntu0.16.04.1) ... Renaming removed key_buffer and myisam-recover options (if present) ERROR: Unable to start MySQL server: mysqld: Can't read dir of '/etc/mysql/conf.d/' (Errcode: 2 - No such file or directory) mysqld: [ERROR] Fatal error in defaults handling. Program aborted! Please take a look at https://wiki.debian.org/Teams/MySQL/FAQ for tips on fixing common upgrade issues. Once the problem is resolved, run apt-get --fix-broken install to retry. dpkg: error processing package mysql-server-5.7 (--configure): subprocess installed post-installation script returned error exit status 1 No apport report written because the error message indicates its a followup error from a previous failure. dpkg: dependency problems prevent configuration of mysql-server: mysql-server depends on mysql-server-5.7; however: Package mysql-server-5.7 is not configured yet. dpkg: error processing package mysql-server (--configure): dependency problems - leaving unconfigured Setting up mysql-client (5.7.30-0ubuntu0.16.04.1) ... Errors were encountered while processing: mysql-server-5.7 mysql-server E: Sub-process /usr/bin/dpkg returned an error code (1) hadoopwct@ubuntu:~$ sudo mysql_secure_installation mysql_secure_installation: Can't read dir of '/etc/mysql/conf.d/' (Errcode: 2 - No such file or directory) mysql_secure_installation: [ERROR] Fatal error in defaults handling. Program aborted! hadoopwct@ubuntu:~$ mysql -u root -p mysql: Can't read dir of '/etc/mysql/conf.d/' (Errcode: 2 - No such file or directory) mysql: [ERROR] Fatal error in defaults handling. Program aborted!这个错误差依赖，需要在 /etc/apt/sources.list 文件中像下面这样添加一行:deb http://cz.archive.ubuntu.com/ubuntu xenial-updates main连接 然后执行：sudo apt-get update 命令 执行安装命令发现还会出错，需要进行卸载mysql，如下命令：
wct@ubuntu:~$ sudo apt-get remove mysql-server mysql-client wct@ubuntu:~$ sudo rm /var/lib/mysql/ -R pwct@ubuntu:~$ sudo rm /etc/mysql/ -R wct@ubuntu:~$ sudo apt-get autoremove mysql* --purge pwct@ubuntu:~$ sudo apt-get remove apparmor在进行安装，根据提示进行相应输入
wct@ubuntu:~$ sudo apt-get install mysql-server mysql-client初始化MySQL安全脚本
wct@ubuntu:~$ sudo mysql_secure_installationmysql_secure_installation会涉及是否修改root账号的密码、是否移除匿名用户、是否允许远程登录、是否删除test数据库等
