我正在尝试更新系统，但 mysql 5.7 失败。似乎由于身份验证问题无法连接。
以下是完整的控制台输出：
Reading package lists... Done
Building dependency tree
Reading state information... Done
mysql-server-5.7 is already the newest version (5.7.23-0ubuntu0.16.04.1).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
2 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] y
Setting up mysql-server-5.7 (5.7.23-0ubuntu0.16.04.1) ...
Renaming removed key_buffer and myisam-recover options (if present)
mysql_upgrade: Got error: 1045: Access denied for user 'root'@'localhost' (using password: NO) while connecting to the MySQL server
Upgrade process encountered error and will not continue.
mysql_upgrade failed with exit status 11
dpkg: error processing package mysql-server-5.7 (--configure):
subprocess installed post-installation script returned error exit status 1
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
Errors were encountered while processing:
mysql-server-5.7
mysql-server
E: Sub-process /usr/bin/dpkg returned an error code (1)
重要提示：
mysql_upgrade: Got error: 1045: Access denied for user 'root'@'localhost'
我可以使用“mysql -u root -p”命令顺利登录。我不使用密码登录服务器，因为如果需要的话，我会使用 ssh 密钥。
为什么这个问题现在会出现？如何解决？我也已经有一段时间没有更新系统了，但这是唯一有问题的软件包。
答案1
您可以尝试通过 Unix Socket 启用无密码登录 mySQL，该功能通常默认启用，但也许您已经更改了它。
登录到mysqlroot shell 并运行以下命令：
grant usage on *.* to 'root'@'localhost' identified via unix_socket;
如果这不起作用，请尝试添加~/.my.cnf包含以下内容的文件：
[client]
user=root
password=your_password
使其仅所有者（和 root）可读：
chmod 600 ~/.my.cnf
然后重试。