Comment 3 for bug 1678583

Reporting back after doing the purge and install instructions.

Here is the output after the apt install instruction:

==================

nexargi@server-02:/$ sudo apt install mysql-server
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  aptitude-common g++-4.8 gcc-4.9-base libboost-iostreams1.54.0 libboost-iostreams1.58.0 libc-ares2 libck-connector0 libcwidget3 libdbd-mysql-perl libdbi-perl libept1.4.12 libgcrypt11-dev libgcrypt20-dev
  libgnutlsxx27 libgpg-error-dev libisl10 libprocps3 libsigc++-2.0-0c2a libstdc++-4.8-dev libterm-readkey-perl libv8-3.14.5 libxapian22v5 linux-image-3.11.0-15-generic linux-image-extra-3.11.0-15-generic
  python-chardet python-cheetah python-configobj python-json-pointer python-jsonpatch python-oauth python-pkg-resources python-prettytable python-requests python-serial python-six python-urllib3 python-yaml
Use 'sudo apt autoremove' to remove them.
The following additional packages will be installed:
  mysql-server-5.7 mysql-server-core-5.7
Suggested packages:
  mailx tinyca
Recommended packages:
  libhtml-template-perl
The following NEW packages will be installed:
  mysql-server mysql-server-5.7 mysql-server-core-5.7
0 upgraded, 3 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/10.6 MB of archives.
After this operation, 94.7 MB of additional disk space will be used.
Do you want to continue? [Y/n] Y
N: Ignoring file '50unattended-upgrades.ucf-old' in directory '/etc/apt/apt.conf.d/' as it has an invalid filename extension
Preconfiguring packages ...
Selecting previously unselected package mysql-server-core-5.7.
(Reading database ... 98452 files and directories currently installed.)
Preparing to unpack .../mysql-server-core-5.7_5.7.17-0ubuntu0.16.04.1_amd64.deb ...
Unpacking mysql-server-core-5.7 (5.7.17-0ubuntu0.16.04.1) ...
Selecting previously unselected package mysql-server-5.7.
Preparing to unpack .../mysql-server-5.7_5.7.17-0ubuntu0.16.04.1_amd64.deb ...
Unpacking mysql-server-5.7 (5.7.17-0ubuntu0.16.04.1) ...
Selecting previously unselected package mysql-server.
Preparing to unpack .../mysql-server_5.7.17-0ubuntu0.16.04.1_all.deb ...
Unpacking mysql-server (5.7.17-0ubuntu0.16.04.1) ...
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 (5.7.17-0ubuntu0.16.04.1) ...
Setting up mysql-server-5.7 (5.7.17-0ubuntu0.16.04.1) ...
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)
ERROR: Unable to start MySQL server:
mysqld: Can't read dir of '/etc/mysql/mysql.conf.d/' (Errcode: 13 - Permission denied)
mysqld: [ERROR] Fatal error in defaults handling. Program aborted!
Please take a look at https://wiki.debian.org/Teams/MySQL/FAQ for tips on fixing common upgrade issues.
Once the problem is resolved, run apt-get --fix-broken install to retry.
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) ...
Processing triggers for ureadahead (0.100.0-19) ...
Errors were encountered while processing:
 mysql-server-5.7
 mysql-server
N: Ignoring file '50unattended-upgrades.ucf-old' in directory '/etc/apt/apt.conf.d/' as it has an invalid filename extension
E: Sub-process /usr/bin/dpkg returned an error code (1)

==============

Looking through the above the ERROR is shown as :

ERROR: Unable to start MySQL server:
mysqld: Can't read dir of '/etc/mysql/mysql.conf.d/' (Errcode: 13 - Permission denied)

=============

Here is the directory listing of /etc/mysql immediately after the process finished:

nexargi@server-02:/$ cd /etc/mysql
nexargi@server-02:/etc/mysql$ ls -l
total 16
drwxr-xr-x 2 mysql mysql 4096 Apr 2 11:08 conf.d
-rwxr-xr-x 1 root root 120 Jan 18 21:46 debian-start
lrwxrwxrwx 1 root root 24 Apr 2 11:08 my.cnf -> /etc/alternatives/my.cnf
-rw-r--r-- 1 root root 682 Jul 11 2016 mysql.cnf
drwxr-xr-x 2 root root 4096 Apr 2 11:08 mysql.conf.d

====

I'm not sure why mysqld can't read /etc/mysql/mysql.conf.d directory. However that is where I believe the error is.

All advice / help would be greatly appreciated.

Thanks