远程访问条件

mysql允许远程访问有两个必要条件

• 外部能访问到mysql开启的端口
• 用户有权限访问

配置

1、配置绑定地址

mysql配置绑定的地址是127.0.0.1，只允许本机连接。为使其他主机可以访问mysql服务，需要绑定非本地ip，或0.0.0.0即可。配置文件存在于/etc/mysql/mysql.conf.d/mysqld.cnf，如果此文件没有相关的配置内容，可手动添加，或将以下内容复制过去即可。

#
# The MySQL database server configuration file.
#
# One can use all long options that the program supports.
# Run program with --help to get a list of available options and with
# --print-defaults to see which it would actually understand and use.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html

# Here is entries for some specific programs
# The following values assume you have at least 32M ram

[mysqld]
#
# * Basic Settings
#
user		= mysql
# pid-file	= /var/run/mysqld/mysqld.pid
# socket	= /var/run/mysqld/mysqld.sock
# port		= 3306
# datadir	= /var/lib/mysql


# If MySQL is running as a replication slave, this should be
# changed. Ref https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_tmpdir
# tmpdir		= /tmp
#
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
bind-address		= 127.0.0.1
mysqlx-bind-address	= 127.0.0.1
#
# * Fine Tuning
#
key_buffer_size		= 16M
# max_allowed_packet	= 64M
# thread_stack		= 256K

# thread_cache_size       = -1

# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched
myisam-recover-options  = BACKUP

# max_connections        = 151

# table_open_cache       = 4000

#
# * Logging and Replication
#
# Both location gets rotated by the cronjob.
#
# Log all queries
# Be aware that this log type is a performance killer.
# general_log_file        = /var/log/mysql/query.log
# general_log             = 1
#
# Error log - should be very few entries.
#
log_error = /var/log/mysql/error.log
#
# Here you can see queries with especially long duration
# slow_query_log		= 1
# slow_query_log_file	= /var/log/mysql/mysql-slow.log
# long_query_time = 2
# log-queries-not-using-indexes
#
# The following can be used as easy to replay backup logs or for replication.
# note: if you are setting up a replication slave, see README.Debian about
#       other settings you may need to change.
# server-id		= 1
# log_bin			= /var/log/mysql/mysql-bin.log
# binlog_expire_logs_seconds	= 2592000
max_binlog_size   = 100M
# binlog_do_db		= include_database_name
# binlog_ignore_db	= include_database_name

2、授权用户

用户访问信息在mysql数据库的user中设定，可通过修改user表，来授权用户访问。

改表

1. 修改已有用户的host字段
   修改mysql的user表，host字段为指定ip即可。如果想任意主机都可以连接，可以使用%

update user set host = '%' where user = 'root';

2. 新建远程连接用户

grant all on *.* to admin@'%' identified by '123456' with grant option;

授权

修改表后并不会生效，需要执行以下sql使用修改生效。

flush privileges;