显示[Note]用户'UNKNOWN_MYSQL_USER'的访问被拒绝的MySQL 5.7.17启动日志 [英] MySQL 5.7.17 startup log showing [Note] Access denied for user 'UNKNOWN_MYSQL_USER'

问题描述

我在Centos 6上运行了MySQL Community Server版本5.7.17，所有内容均带有全新安装，Centos 6带有最小"选项安装，MySQL由官方yum repo安装.

I have MySQL Community Server version 5.7.17 running on Centos 6, everything comes with clean install, Centos 6 installed with "minimal" options, MySQL installed by official yum repo.

启动MySQL服务器时，日志"/var/log/mysqld.log"显示为:

When I start MySQL server, the log "/var/log/mysqld.log" showing:

[Note] Access denied for user 'UNKNOWN_MYSQL_USER'@'localhost' (using password: NO)

它出现在日志的最后一行，我试图这样做:

It appears at the last line of the log, I tried to:

mysql> select * from mysql.user;

我只能看到默认情况下附带的"root"和"mysql.sys"，我是否可以知道用户'UNKNOWN_MYSQL_USER'@'localhost'是什么? 5.7.17版本中有什么新东西吗?

I can only see "root" and "mysql.sys" which comes by default, may I know what is the user 'UNKNOWN_MYSQL_USER'@'localhost'? is that something new in the version 5.7.17?

谢谢.

推荐答案

没什么可担心的:) 由于某人/某人试图访问MySQL服务器，但连接失败，因此您收到此消息.您可以通过尝试使用错误的用户名和/或密码连接到MySQL并查看错误日志文件来重现此行为.

Nothing to worry about :) You are receiving this message because someone/something tried to access MySQL server, but connection failed. You can reproduce this behaviour by attempting to connect to MySQL with wrong user and/or password and watch the error log file.

在您的情况下，似乎是/etc/init.d/mysqld本身试图测试MySQL服务器是否已启动并正在运行.

In your case, looks like it's the /etc/init.d/mysqld itself trying to test if MySQL server is up and running.

TIMEOUT="$STARTTIMEOUT"
while [ $TIMEOUT -gt 0 ]; do
   RESPONSE=`/usr/bin/mysqladmin --socket="$socketfile" --user=UNKNOWN_MYSQL_USER ping 2>&1`

默认情况下，在MySQL 5.7中，错误日志的详细程度设置为3(错误，警告和注释)，这就是为什么您在错误日志文件中看到此消息的原因.

By default, in MySQL 5.7 the error log verbosity is set to 3 (errors, warnings and notes), this is why you're seeing this message in the error log file.

mysql> show variables like 'log_error_verbosity';
+---------------------+-------+
| Variable_name       | Value |
+---------------------+-------+
| log_error_verbosity | 3     |
+---------------------+-------+

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