Failing to build Dockerfile

[rept]

When I try to build the (unmodified) Dockerfile I'm getting this:

debconf: unable to initialize frontend: Dialog
debconf: (TERM is not set, so the dialog frontend is not usable.)
debconf: falling back to frontend: Readline
debconf: unable to initialize frontend: Readline
debconf: (This frontend requires a controlling tty.)
debconf: falling back to frontend: Teletype
Configuring mysql-server-5.5
----------------------------

While not mandatory, it is highly recommended that you set a password for the 
MySQL administrative "root" user.

If this field is left blank, the password will not be changed.

New password for the MySQL "root" user: 
Use of uninitialized value $_[1] in join or string at /usr/share/perl5/Debconf/DbDriver/Stack.pm line 111.
chfn: PAM: System error
adduser: `/usr/bin/chfn -f MySQL Server mysql' returned error code 1. Exiting.
Use of uninitialized value $val in substitution (s///) at /usr/share/perl5/Debconf/Format/822.pm line 83.
Use of uninitialized value $val in concatenation (.) or string at /usr/share/perl5/Debconf/Format/822.pm line 84.
dpkg: error processing archive /var/cache/apt/archives/mysql-server-5.5_5.5.41-0ubuntu0.14.04.1_amd64.deb (--unpack):
 subprocess new pre-installation script returned error exit status 1

Any clues as to why this is?

[nkratzke]

I double checked it with my Docker installation and could not reproduce your error. Maybe you should update your docker installation?