有类似的问题，但没有一个能解决我的问题，所以如果我遗漏了什么，我深表歉意。
mysqldbcopy当我的实例用完可用空间时，我正在使用复制数据库。Mysql 崩溃并且无法重新启动。为了释放空间，我从 中删除了具有新数据库名称的文件夹/var/lib/mysql。Mysql 仍然无法重新启动，因此我删除/var/lib/mysql并尝试使用 重新安装sudo mysql_install_db。这有效，但我无法再使用或不使用密码登录，也无法重置密码。
作为最后一次尝试，我刚刚做了
sudo apt-get remove --purge mysql*
但当我去重新安装时，我得到了
Do you want to continue? [Y/n] y
Preconfiguring packages ...
Selecting previously unselected package mysql-server-core-5.7.
(Reading database ... 94735 files and directories currently installed.)
Preparing to unpack .../mysql-server-core-5.7_5.7.18-0ubuntu0.16.04.1_amd64.deb ...
Unpacking mysql-server-core-5.7 (5.7.18-0ubuntu0.16.04.1) ...
Selecting previously unselected package mysql-server-5.7.
Preparing to unpack .../mysql-server-5.7_5.7.18-0ubuntu0.16.04.1_amd64.deb ...
Unpacking mysql-server-5.7 (5.7.18-0ubuntu0.16.04.1) ...
Selecting previously unselected package mysql-server.
Preparing to unpack .../mysql-server_5.7.18-0ubuntu0.16.04.1_all.deb ...
Unpacking mysql-server (5.7.18-0ubuntu0.16.04.1) ...
Processing triggers for man-db (2.7.5-1) ...
Processing triggers for systemd (229-4ubuntu16) ...
Processing triggers for ureadahead (0.100.0-19) ...
Setting up mysql-server-core-5.7 (5.7.18-0ubuntu0.16.04.1) ...
Setting up mysql-server-5.7 (5.7.18-0ubuntu0.16.04.1) ...
update-alternatives: using /etc/mysql/mysql.cnf to provide /etc/mysql/my.cnf (my.cnf) in auto mode
Renaming removed key_buffer and myisam-recover options (if present)
mysql_upgrade: Got error: 1045: Access denied for user 'debian-sys-maint'@'localhost' (using password: YES) 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
Processing triggers for systemd (229-4ubuntu16) ...No apport report written because the error message indicates its a followup error from a previous failure.
Processing triggers for ureadahead (0.100.0-19) ...
Errors were encountered while processing:
mysql-server-5.7
mysql-server
E: Sub-process /usr/bin/dpkg returned an error code (1)
我没什么主意了。任何建议都值得赞赏。
输出sudo dpkg -r --force-all mysql-server mysql-server-5.7 && sudo apt install -f：
$ sudo dpkg -r --force-all mysql-server mysql-server-5.7 && sudo apt install -f
(Reading database ... 94924 files and directories currently installed.)
Removing mysql-server (5.7.18-0ubuntu0.16.04.1) ...
Removing mysql-server-5.7 (5.7.18-0ubuntu0.16.04.1) ...
update-alternatives: using /etc/mysql/my.cnf.fallback to provide /etc/mysql/my.cnf (my.cnf) in auto mode
Processing triggers for man-db (2.7.5-1) ...
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
libcgi-fast-perl libcgi-pm-perl libencode-locale-perl libevent-core-2.0-5 libfcgi-perl
libhtml-parser-perl libhtml-tagset-perl libhtml-template-perl libhttp-date-perl
libhttp-message-perl libio-html-perl liblwp-mediatypes-perl libtimedate-perl liburi-perl
mysql-server-core-5.7 python-mysql.connector
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 50 not upgraded.
输出sudo apt-get install mysql-server
$ sudo apt-get install mysql-server
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following package was automatically installed and is no longer required:
python-mysql.connector
Use 'sudo apt autoremove' to remove it.
The following additional packages will be installed:
mysql-server-5.7
Suggested packages:
mailx tinyca
The following NEW packages will be installed:
mysql-server mysql-server-5.7
0 upgraded, 2 newly installed, 0 to remove and 50 not upgraded.
Need to get 0 B/2,565 kB of archives.
After this operation, 48.5 MB of additional disk space will be used.
Do you want to continue? [Y/n] y
Preconfiguring packages ...
Selecting previously unselected package mysql-server-5.7.
(Reading database ... 94847 files and directories currently installed.)
Preparing to unpack .../mysql-server-5.7_5.7.18-0ubuntu0.16.04.1_amd64.deb ...
Unpacking mysql-server-5.7 (5.7.18-0ubuntu0.16.04.1) ...
Selecting previously unselected package mysql-server.
Preparing to unpack .../mysql-server_5.7.18-0ubuntu0.16.04.1_all.deb ...
Unpacking mysql-server (5.7.18-0ubuntu0.16.04.1) ...
Processing triggers for systemd (229-4ubuntu16) ...
Processing triggers for ureadahead (0.100.0-19) ...
Processing triggers for man-db (2.7.5-1) ...
Setting up mysql-server-5.7 (5.7.18-0ubuntu0.16.04.1) ...
update-alternatives: using /etc/mysql/mysql.cnf to provide /etc/mysql/my.cnf (my.cnf) in auto mode
Renaming removed key_buffer and myisam-recover options (if present)
mysql_upgrade: Got error: 1045: Access denied for user 'debian-sys-maint'@'localhost' (using password: YES) 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
No apport report written because the error message indicates its a followup error from a previous failure.
Errors were encountered while processing:
mysql-server-5.7
mysql-server
E: Sub-process /usr/bin/dpkg returned an error code (1)
答案1
所以我尝试mysqld在终端中运行并看到
mysqld_safe Directory '/var/run/mysqld' for UNIX socket file don't e$ists.
这让我只需创建该目录（并更新权限）。然后我可以
sudo mkdir -p /var/run/mysqld
sudo chown mysql:mysql /var/run/mysqld
然后我可以以安全模式启动
sudo /usr/bin/mysqld_safe --skip-grant-tables &
并手动设置密码
USE mysql
UPDATE mysql.user
SET authentication_string=PASSWORD('hunter4')
WHERE user='root' AND host='localhost';