How to avoid error 'debconf: unable to initialize frontend: Dialog'

[Fernando Correia]

How to avoid the error 'debconf: unable to initialize frontend: Dialog' when installing packages via apt-get when building a derived image?

For instance, this Dockerfile:

FROM phusion/baseimage:0.9.10

MAINTAINER Test <te...@example.com>

RUN \

  DEBIAN_FRONTEND=noninteractive && \

  apt-get -qq update && \

  apt-get -qqy install dialog && \

  apt-get -qqy install git

produces this output:

Sending build context to Docker daemon  2.56 kB

Sending build context to Docker daemon 

Step 0 : FROM phusion/baseimage:0.9.10

 ---> 35c2d5a269ff

Step 1 : MAINTAINER Test <te...@example.com>

 ---> Running in 23ae4c9361c6

 ---> e3506a23995e

Removing intermediate container 23ae4c9361c6

Step 2 : RUN  DEBIAN_FRONTEND=noninteractive &&  apt-get -qq update &&  apt-get -qqy install git

 ---> Running in 5143231d8bba

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

dpkg-preconfigure: unable to re-open stdin: 

Selecting previously unselected package rsync.

(Reading database ... 14905 files and directories currently installed.)

Preparing to unpack .../rsync_3.1.0-2ubuntu0.1_amd64.deb ...

Unpacking rsync (3.1.0-2ubuntu0.1) ...

Selecting previously unselected package liberror-perl.

Preparing to unpack .../liberror-perl_0.17-1.1_all.deb ...

Unpacking liberror-perl (0.17-1.1) ...

Selecting previously unselected package git-man.

Preparing to unpack .../git-man_1%3a1.9.1-1_all.deb ...

Unpacking git-man (1:1.9.1-1) ...

Selecting previously unselected package git.

Preparing to unpack .../git_1%3a1.9.1-1_amd64.deb ...

Unpacking git (1:1.9.1-1) ...

Selecting previously unselected package patch.

Preparing to unpack .../patch_2.7.1-4ubuntu1_amd64.deb ...

Unpacking patch (2.7.1-4ubuntu1) ...

Processing triggers for ureadahead (0.100.0-16) ...

Setting up rsync (3.1.0-2ubuntu0.1) ...

 Removing any system startup links for /etc/init.d/rsync ...

update-rc.d: warning: default stop runlevel arguments (0 1 6) do not match rsync Default-Stop values (none)

 Adding system startup for /etc/init.d/rsync ...

   /etc/rc0.d/K20rsync -> ../init.d/rsync

   /etc/rc1.d/K20rsync -> ../init.d/rsync

   /etc/rc6.d/K20rsync -> ../init.d/rsync

   /etc/rc2.d/S20rsync -> ../init.d/rsync

   /etc/rc3.d/S20rsync -> ../init.d/rsync

   /etc/rc4.d/S20rsync -> ../init.d/rsync

   /etc/rc5.d/S20rsync -> ../init.d/rsync

invoke-rc.d: policy-rc.d denied execution of restart.

Setting up liberror-perl (0.17-1.1) ...

Setting up git-man (1:1.9.1-1) ...

Setting up git (1:1.9.1-1) ...

Setting up patch (2.7.1-4ubuntu1) ...

Processing triggers for ureadahead (0.100.0-16) ...

 ---> 07510f75f733

Removing intermediate container 5143231d8bba

Successfully built 07510f75f733

Installing the package dialog has no effect; the message still appears on subsequent apt-get installs.