Raspbian - dpkg error when trying to install mysql-server - mysql

Question

I'm running a lighttpd web server on my Raspberry Pi and I'm trying to add php and mysql support. I'm currently trying to install mysql-server with the command
'sudo apt-get install mysql-server'
which results in the following error:
[my user name]#raspberrypi:~ $ sudo apt-get install mysql-server
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
libaio1 libhtml-template-perl mysql-server-5.5 mysql-server-core-5.5
Suggested packages:
libipc-sharedcache-perl mailx tinyca
The following NEW packages will be installed:
libaio1 libhtml-template-perl mysql-server mysql-server-5.5
mysql-server-core-5.5
0 upgraded, 5 newly installed, 0 to remove and 15 not upgraded.
Need to get 0 B/4,938 kB of archives.
After this operation, 46.0 MB of additional disk space will be used.
Do you want to continue? [Y/n] y
WARNING: The following packages cannot be authenticated!
libaio1 mysql-server-core-5.5 mysql-server-5.5 libhtml-template-perl
mysql-server
Install these packages without verification? [y/N] y
Preconfiguring packages ...
Selecting previously unselected package libaio1:armhf.
(Reading database ... 121517 files and directories currently installed.)
Preparing to unpack .../libaio1_0.3.110-1_armhf.deb ...
Unpacking libaio1:armhf (0.3.110-1) ...
Selecting previously unselected package mysql-server-core-5.5.
Preparing to unpack .../mysql-server-core-5.5_5.5.52-0+deb8u1_armhf.deb ...
Unpacking mysql-server-core-5.5 (5.5.52-0+deb8u1) ...
Preparing to unpack .../mysql-server-5.5_5.5.52-0+deb8u1_armhf.deb ...
Aborting downgrade from (at least) 10.0 to 5.5.
If are sure you want to downgrade to 5.5, remove the file
/var/lib/mysql/debian-*.flag and try installing again.
dpkg: error processing archive /var/cache/apt/archives/mysql-server-5.5_5.5.52-0+deb8u1_armhf.deb (--unpack):
subprocess new pre-installation script returned error exit status 1
Selecting previously unselected package libhtml-template-perl.
Preparing to unpack .../libhtml-template-perl_2.95-1_all.deb ...
Unpacking libhtml-template-perl (2.95-1) ...
Selecting previously unselected package mysql-server.
Preparing to unpack .../mysql-server_5.5.52-0+deb8u1_all.deb ...
Unpacking mysql-server (5.5.52-0+deb8u1) ...
Processing triggers for man-db (2.7.0.2-5) ...
Errors were encountered while processing:
/var/cache/apt/archives/mysql-server-5.5_5.5.52-0+deb8u1_armhf.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)
I know the same problem was reported here:
https://raspberrypi.stackexchange.com/questions/28312/raspberry-pi-2-installing-mysql-server
But the solution in that case seemed to be enabling the loopback interface. In my case, the loopback interface is working fine but that doesn't solve my problem.
ifconfig output:
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:1096 errors:0 dropped:0 overruns:0 frame:0
TX packets:1096 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:91408 (89.2 KiB) TX bytes:91408 (89.2 KiB)
I tried the following commands, repeatedly, with no result:
'sudo apt-get -f install'
'sudo apt-get autoremove'
'sudo apt-get autoclean'
'sudo apt-get update'
'sudo apt-get upgrade'
'sudo dpkg --configure -a'

Answer 1

The problem is in the preinstall script. It should install perfectly. You have some options here:
1) Open a bug at Debian Bug Tracking System (BTS). Make sure you are using the latest version.
2) Try to fix it by yourself.
If you decide to go with 2), you want to make this script verbose, so, edit a file name /var/lib/dpkg/info/mysql-server-5.5_5.5.52-0*.preinst
Then replace the initial line from:
#!/bin/sh
to
#!/bin/sh -x
Then, call # apt-get install -f and see the new log messages

Answer 2

Try with:
sudo apt-get autoremove --purge <package>