MySQL只使用unix套接字禁用tcp

一般场景下nginx,php,mysql都是装在一台机器上的，那么没必要使用TCP模式来连接彼此，而是使用unix socket方式。

对于直接使用apt-get方式安装的mysql，其8.x版本的配置文件是/etc/mysql/mysql.conf.d/mysqld.cnf，在其中添加skip-networking即可禁用tcp监听

[mysqld]
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
datadir         = /var/lib/mysql
log-error       = /var/log/mysql/error.log
skip-networking

默认是tcp和unix socket都监听的。

修改完成后重启服务systemctl restart mysql，然后查看网络情况netstat -l

Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0 0.0.0.0:http            0.0.0.0:*               LISTEN     
tcp        0      0 0.0.0.0:1023            0.0.0.0:*               LISTEN     
tcp6       0      0 [::]:1023               [::]:*                  LISTEN     
Active UNIX domain sockets (only servers)
Proto RefCnt Flags       Type       State         I-Node   Path
unix  2      [ ACC ]     STREAM     LISTENING     11383    /run/systemd/journal/io.systemd.journal
unix  2      [ ACC ]     STREAM     LISTENING     136333   /run/screen/S-root/42875.s
unix  2      [ ACC ]     STREAM     LISTENING     136458   /run/php/php7.4-fpm.sock
unix  2      [ ACC ]     STREAM     LISTENING     135845   /run/user/0/systemd/private
unix  2      [ ACC ]     STREAM     LISTENING     135848   /run/user/0/gnupg/S.dirmngr
unix  2      [ ACC ]     STREAM     LISTENING     135850   /run/user/0/gnupg/S.gpg-agent.browser
unix  2      [ ACC ]     STREAM     LISTENING     135852   /run/user/0/gnupg/S.gpg-agent.extra
unix  2      [ ACC ]     STREAM     LISTENING     135854   /run/user/0/gnupg/S.gpg-agent.ssh
unix  2      [ ACC ]     STREAM     LISTENING     135856   /run/user/0/gnupg/S.gpg-agent
unix  2      [ ACC ]     STREAM     LISTENING     140509   /var/run/mysqld/mysqlx.sock
unix  2      [ ACC ]     STREAM     LISTENING     141471   /var/run/mysqld/mysqld.sock
unix  2      [ ACC ]     STREAM     LISTENING     10801    /run/dbus/system_bus_socket
unix  2      [ ACC ]     STREAM     LISTENING     10530    /run/systemd/private
unix  2      [ ACC ]     STREAM     LISTENING     10532    /run/systemd/userdb/io.systemd.DynamicUser
unix  2      [ ACC ]     STREAM     LISTENING     10533    /run/systemd/io.system.ManagedOOM
unix  2      [ ACC ]     STREAM     LISTENING     10545    /run/systemd/fsck.progress
unix  2      [ ACC ]     STREAM     LISTENING     10553    /run/systemd/journal/stdout
unix  2      [ ACC ]     SEQPACKET  LISTENING     10555    /run/udev/control

已经没有3306端口监听了。