mariadb 失败后安装 mysql-server

Question

使用 Kubuntu 17.04。我试图安装 mariadb，但没有成功，所以现在我试图恢复到 mysql。但是，当我尝试安装 mysql 时，它也不再工作：

~# apt-get install mysql-server
Reading package lists... Done
Building dependency tree       
Reading state information... Done
mysql-server is already the newest version (5.7.19-0ubuntu0.17.04.1).
You might want to run 'apt --fix-broken install' to correct these.
The following packages have unmet dependencies.
 mysql-server : Depends: mysql-server-5.7 but it is not going to be installed
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).

然后我尝试了建议 --fix-broken：

~# apt-get --fix-broken install
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Correcting dependencies... Done
The following additional packages will be installed:
  mysql-server-5.7
Suggested packages:
  tinyca
The following NEW packages will be installed
  mysql-server-5.7
0 to upgrade, 1 to newly install, 0 to remove and 0 not to upgrade.
5 not fully installed or removed.
Need to get 3,363 kB of archives.
After this operation, 50.0 MB of additional disk space will be used.
Do you want to continue? [Y/n] 
Get:1 http://gb.archive.ubuntu.com/ubuntu zesty-updates/main amd64 mysql-server-5.7 amd64 5.7.19-0ubuntu0.17.04.1 [3,363 kB]
Fetched 3,363 kB in 1s (3,049 kB/s)           
Preconfiguring packages ...
Selecting previously unselected package mysql-server-5.7.
(Reading database ... 304498 files and directories currently installed.)
Preparing to unpack .../mysql-server-5.7_5.7.19-0ubuntu0.17.04.1_amd64.deb ...
Failed to stop mysql.service: Unit mysql.service not loaded.
invoke-rc.d: initscript mysql, action "stop" failed.
invoke-rc.d returned 5
There is a MySQL server running, but we failed in our attempts to stop it.
Stop it yourself and try again!
dpkg: error processing archive /var/cache/apt/archives/mysql-server-5.7_5.7.19-0ubuntu0.17.04.1_amd64.deb (--unpack):
 subprocess new pre-installation script returned error exit status 1
Errors were encountered while processing:
 /var/cache/apt/archives/mysql-server-5.7_5.7.19-0ubuntu0.17.04.1_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

现在有点卡住了。谁能帮我让我的系统再次稳定？

更新：尝试运行建议的命令，但这并没有解决问题：

~$ sudo service mysql stop
Failed to stop mysql.service: Unit mysql.service not loaded.

~$ sudo apt -f install
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Correcting dependencies... Done
The following additional packages will be installed:
  mysql-server-5.7
Suggested packages:
  tinyca
The following NEW packages will be installed
  mysql-server-5.7
0 to upgrade, 1 to newly install, 0 to remove and 5 not to upgrade.
5 not fully installed or removed.
Need to get 0 B/3,363 kB of archives.
After this operation, 50.0 MB of additional disk space will be used.
Do you want to continue? [Y/n] 
Preconfiguring packages ...
(Reading database ... 304498 files and directories currently installed.)
Preparing to unpack .../mysql-server-5.7_5.7.19-0ubuntu0.17.04.1_amd64.deb ...
Failed to stop mysql.service: Unit mysql.service not loaded.
invoke-rc.d: initscript mysql, action "stop" failed.
invoke-rc.d returned 5
There is a MySQL server running, but we failed in our attempts to stop it.
Stop it yourself and try again!
dpkg: error processing archive /var/cache/apt/archives/mysql-server-5.7_5.7.19-0ubuntu0.17.04.1_amd64.deb (--unpack):
 subprocess new pre-installation script returned error exit status 1
Errors were encountered while processing:
 /var/cache/apt/archives/mysql-server-5.7_5.7.19-0ubuntu0.17.04.1_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

~$ sudo pkill mysqld
~$ sudo killall mysqld
mysqld: no process found

~$ sudo apt -f install
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Correcting dependencies... Done
The following additional packages will be installed:
  mysql-server-5.7
Suggested packages:
  tinyca
The following NEW packages will be installed
  mysql-server-5.7
0 to upgrade, 1 to newly install, 0 to remove and 5 not to upgrade.
5 not fully installed or removed.
Need to get 0 B/3,363 kB of archives.
After this operation, 50.0 MB of additional disk space will be used.
Do you want to continue? [Y/n] 
Preconfiguring packages ...
(Reading database ... 304498 files and directories currently installed.)
Preparing to unpack .../mysql-server-5.7_5.7.19-0ubuntu0.17.04.1_amd64.deb ...
Failed to stop mysql.service: Unit mysql.service not loaded.
invoke-rc.d: initscript mysql, action "stop" failed.
invoke-rc.d returned 5
There is a MySQL server running, but we failed in our attempts to stop it.
Stop it yourself and try again!
dpkg: error processing archive /var/cache/apt/archives/mysql-server-5.7_5.7.19-0ubuntu0.17.04.1_amd64.deb (--unpack):
 subprocess new pre-installation script returned error exit status 1
Errors were encountered while processing:
 /var/cache/apt/archives/mysql-server-5.7_5.7.19-0ubuntu0.17.04.1_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

Answer 1

我在 Ubuntu 17.04 上尝试从 MySQL 升级到 MariaDB 时遇到了同样的问题 无法安装 MariaDB，因为安装后脚本认为它无法启动服务器（超时错误但服务器已启动）。无法恢复到 MySQL，因为安装脚本认为它无法停止服务器，即使它实际上已停止。

使用 apt 卸载既困难又过度，因为它试图根据 MySQL 客户端库卸载每个包。

这是我恢复到 MySQL 然后升级到 MariaDB 的解决方案。

1) 检测所有 MariaDB 和 MySQL 包

apt search mariadb | grep "\[install"

和

apt search mysql | grep "\[install"

2) 强制卸载所有 MariaDB 和 MySQL 包（服务器、客户端、库）以清理混乱

sudo dpkg --force depends --purge <package> <package> ...

3) 清理 /etc 和 /var/lib/mysql 中的剩余数据

注意：我首先尝试使用我的配置和数据文件安装 MariaDB 或 MySQL，但每次都失败。

sudo rm -rf /var/lib/mysql* /etc/mysql

如果您想坚持使用 MySQL 并且在第一次 MariaDB 升级尝试时在 /var/lib/mysql-5.7 中没有 /var/lib/mysql 的副本，您应该只移动 /var/lib/mysql /var /lib/mysql-5.7 而不是删除它。

4) 修复系统

sudo apt-get --fix-broken install
sudo apt autoremove
sudo reboot

5) 取回 MySQL 数据

--fix-broken 安装重新安装了一个干净的 MySQL（不是 MariaDB，因为 Ubuntu 似乎喜欢那样）。

sudo service mysql stop
mv /var/lib/mysql*5.7 /var/lib/mysql
sudo service mysql start

如果您想转到第 6 步，您应该立即备份所有数据库。

6) 最后升级到 MariaDB

如果您已经有备份，则可以跳过第 5 步。

sudo apt-get install mariadb-server

是的，这是我一开始尝试的，但这次有效！您可以重新创建您的数据库用户，然后恢复您的数据库，因为 MariaDB 不想升级 MySQL 5.7 基础。