Why does this apt-key adv command give an error?

Question

This is a snippet of a Dockerfile that is exhibiting an error that I don't understand:

FROM dorowu/ubuntu-desktop-lxde-vnc
LABEL maintainer "[email protected]"

# Adding keys for ROS
RUN sh -c 'echo "deb http://packages.ros.org/ros/ubuntu $(lsb_release -sc) main" > /etc/apt/sources.list.d/ros-latest.list'
RUN apt-key adv --keyserver hkp://ha.pool.sks-keyservers.net:80 --recv-key 421C365BD9FF1F717815A3895523BAEEB01FA116

Gives this result

RUN apt-key adv --keyserver hkp://ha.pool.sks-keyservers.net:80 --recv-key 421C365BD9FF1F717815A3895523BAEEB01FA116
 ---> Running in 7bb30729ec87
Warning: apt-key output should not be parsed (stdout is not a terminal)
Executing: /tmp/apt-key-gpghome.HkofyyhjvI/gpg.1.sh --keyserver hkp://ha.pool.sks-keyservers.net:80 --recv-key 421C365BD9FF1F717815A3895523BAEEB01FA116
gpg: failed to start the dirmngr '/usr/bin/dirmngr': No such file or directory
gpg: connecting dirmngr at '/tmp/apt-key-gpghome.HkofyyhjvI/S.dirmngr' failed: No such file or directory
gpg: keyserver receive failed: No dirmngr
The command '/bin/sh -c apt-key adv --keyserver hkp://ha.pool.sks-keyservers.net:80 --recv-key 421C365BD9FF1F717815A3895523BAEEB01FA116' returned a non-zero code: 2

Answer 1

According to this post here, you need to install dirmngr. I also needed to install gnupg in order to get this to work on my local docker container when testing.

I updated your Dockerfile code below with my changes:

FROM dorowu/ubuntu-desktop-lxde-vnc
LABEL maintainer "[email protected]"

# Update
RUN apt-get update && \
  apt-get upgrade -y

# Install required packages
RUN apt-get install -y \
  dirmngr \
  gnupg

# Adding keys for ROS
RUN sh -c 'echo "deb http://packages.ros.org/ros/ubuntu $(lsb_release -sc) main" > /etc/apt/sources.list.d/ros-latest.list'

RUN apt-key adv --keyserver hkp://ha.pool.sks-keyservers.net --recv-key 421C365BD9FF1F717815A3895523BAEEB01FA116

This gave me the following output on the last step:

Step 6/6 : RUN apt-key adv --keyserver hkp://pgp.mit.edu:80 --recv-key 421C365BD9FF1F717815A3895523BAEEB01FA116
 ---> Running in a0cfb3588173
Warning: apt-key output should not be parsed (stdout is not a terminal)
Executing: /tmp/apt-key-gpghome.USze27holj/gpg.1.sh --keyserver hkp://pgp.mit.edu:80 --recv-key 421C365BD9FF1F717815A3895523BAEEB01FA116
gpg: key 5523BAEEB01FA116: public key "ROS Builder <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1

Occasionally this reports back with the following error:

gpg: keyserver receive failed: Cannot assign requested address

That error doesn't seem consistent though, so it could be something with my own network connection.