iRedMail MySQL install prompts for password, hangs

Question

I'm installing iRedMail on a relatively fresh Ubuntu VPS, running 16.04.1 LTS. The iRedMail installer installs MySQL, which halts at this point below, prompting for a password, then echoing characters in plain text, at which point I must kill the installers and force-remove the remnants of the corrupt mysql-server-5.7 package.

root@calesius:~# apt-get install mysql-server
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following additional packages will be installed:
  libcgi-fast-perl libcgi-pm-perl libencode-locale-perl 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-client-5.7 mysql-server-5.7
Suggested packages:
  libdata-dump-perl libipc-sharedcache-perl libwww-perl mailx tinyca
The following NEW packages will be installed:
  libcgi-fast-perl libcgi-pm-perl libencode-locale-perl 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-client-5.7 mysql-server mysql-server-5.7
0 upgraded, 16 newly installed, 0 to remove and 74 not upgraded.
Need to get 0 B/5264 kB of archives.
After this operation, 84.6 MB of additional disk space will be used.
Do you want to continue? [Y/n] Y
Preconfiguring packages ...
Selecting previously unselected package mysql-client-5.7.
(Reading database ... 87430 files and directories currently installed.)
Preparing to unpack .../mysql-client-5.7_5.7.17-0ubuntu0.16.04.1_amd64.deb ...
Unpacking mysql-client-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 ...
Password:

I've tried many different ways of removing and purging all config and files, all to no avail. Nobody else seems to be experiencing this bug at this specific point, and this is a fresh install of the latest supported versions of MySQL and Ubuntu.

Any help is appreciated.

Answer 1

I was able to get to a functioning password prompt by downloading the packages from MySQL's website. apt-get still froze. However, the underlying issue was actually a PAM configuration problem. I had haphazardly included the use_authtok option in my password configuration in /etc/pam.d/, which prevented anything from checking the password. I'm still not sure why the install required it, but at least it worked.