WARNING unable to detect os for base image 'IMG', maybe the base image does not exist

[130s]

Problem

rocker terminates with an error msg. This msg isn't helping me much.

$ rocker --nvidia --x11 registry.gitlab.com/ppp/product/foo/baa:brancheee bash
:
Failed to build detector image
WARNING unable to detect os for base image 'registry.gitlab.com/ppp/product/foo/baa:brancheee', maybe the base image does not exist

More log

``` $ rocker --nvidia --x11 registry.gitlab.com/ppp/product/foo/baa:brancheee bash Active extensions ['nvidia', 'x11'] Step 1/12 : FROM python:3-stretch as detector ---> b9d77e48a75c Step 2/12 : RUN mkdir -p /tmp/distrovenv ---> Using cache ---> 5eb7a7ed5abe Step 3/12 : RUN python3 -m venv /tmp/distrovenv ---> Using cache ---> e3b0ac41824b Step 4/12 : RUN . /tmp/distrovenv/bin/activate && pip install distro pyinstaller==4.0 staticx ---> Running in 8d59b61611dc Collecting distro Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError(': Failed to establish a new connection: [Errno -3] Temporary failure in name resolution')': /simple/distro/ Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError(': Failed to establish a new connection: [Errno -3] Temporary failure in name resolution')': /simple/distro/ Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError(': Failed to establish a new connection: [Errno -3] Temporary failure in name resolution')': /simple/distro/ Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError(': Failed to establish a new connection: [Errno -3] Temporary failure in name resolution')': /simple/distro/ Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError(': Failed to establish a new connection: [Errno -3] Temporary failure in name resolution')': /simple/distro/ Could not find a version that satisfies the requirement distro (from versions: ) No matching distribution found for distro no more output and success not detected Failed to build detector image WARNING unable to detect os for base image 'registry.gitlab.com/ppp/product/foo/baa:brancheee', maybe the base image does not exist ```

Env

Unlike https://github.com/osrf/rocker/issues/127 where smilar/same error msg is seen, docker-py isn't installed.

$ pip uninstall docker-py
DEPRECATION: Python 2.7 reached the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 is no longer maintained. pip 21.0 will drop support for Python 2.7 in January 2021. More details about Python 2 support in pip can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support pip 21.0 will remove support for this functionality.
WARNING: Skipping docker-py as it is not installed.

The Docker image in use is the same as what's used in #139, but the host is different.

$ apt list --installed nvidia*
Listing... Done

$ uname -a
Linux 130s-serval 5.3.0-7648-generic #41~1586790036~18.04~600aeb5~dev-Ubuntu SMP Mon Apr 13 17:49:24  x86_64 x86_64 x86_64 GNU/Linux
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 18.04.5 LTS
Release:        18.04
Codename:       bionic

[130s]

Closing. On the host there's no nvidia* pkgs are available. By removing --nvidia option I bypassed the error.

$ rocker --x11 registry.gitlab.com/ppp/product/foo/baa:brancheee bash

(Note: The host is different from #139, which is also what I recently reported and where nvidia pkgs are present.)