Failure to build 18.04 minimal images due to missing gpg packages

[Philip Roche]

We (CPC) are seeing failures when building 18.04 minimal images with the following errors when adding a PPA.

E: gnupg, gnupg2 and gnupg1 do not seem to be installed, but one of them is required for this operation

I understand that there has been recent changes to which gpg packages are installed in 18.04. Is this a bug or should we be explicitly installing gpg packages now?

We started seeing these build failures on 03-Mar-2018.

This is blocking build of all 18.04 minimal images.

[Steve Langasek (vorlon)]

live-build (3.0~a57-1ubuntu33) bionic; urgency=medium

  * Stop using apt-key to setup secure apt, and instead copy the gpg key
    snippet.

[Sergey Ponomarev (stokito)]

~vorlon can you elaborate on this? A lot of manuals are using apt-key for example to install zulu open jdk http://zulu.org/zuludocs-folder/#ZuluUserGuide/PrepareZuluPlatform/AttachAPTRepositoryUbuntuOrDebianSys.htm
And what exactly you mean saying "copy the gpg key snippet"?

[Thomas Dreibholz (dreibh)]

I just tried to set up pbuilder with the attached /etc/pbuilderrc. Particularly, the configuration needs a PPA, which is added by "OTHERMIRROR" in the pbuilderrc:

sudo rm -f /etc/apt/trusted.gpg
find /etc/apt/trusted.gpg.d/ -name "*.gpg" | xargs --no-run-if-empty -n1 sudo apt-key --keyring /etc/apt/trusted.gpg add
sudo pbuilder create --debootstrapopts --variant=buildd --keyring /etc/apt/trusted.gpg

It neither works for Bionic nor Cosmic:

I: Installing apt-lines
I: adding apt key file /etc/apt/trusted.gpg.
E: gnupg, gnupg2 and gnupg1 do not seem to be installed, but one of them is required for this operation

[Thomas Dreibholz (dreibh)]

Note, that building a Xenial pbuilder environment works with the commands and configuration above (with DISTRIBUTION=xenial in /etc/pbuilerrc). So, apt-key seems to still need gpg in Bionic and Cosmic, and apt-key either needs a fix or have the dependency on gpg.