package docker.io 17.12.1-0ubuntu1 failed to install/upgrade: installed docker.io package post-installation script subprocess returned error exit status 1

[Dharmendra]

Report

ProblemType: Package
DistroRelease: Ubuntu 18.04
Package: docker.io 17.12.1-0ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-34.37-generic 4.15.18
Uname: Linux 4.15.0-34-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
Date: Mon Sep 24 09:38:18 2018
ErrorMessage: installed docker.io package post-installation script subprocess returned error exit status 1
InstallationDate: Installed on 2017-09-23 (366 days ago)
InstallationMedia: Ubuntu 16.04.2 LTS "Xenial Xerus" - Release amd64 (20170215.2)
Python3Details: /usr/bin/python3.6, Python 3.6.6, python3-minimal, 3.6.5-3ubuntu1
PythonDetails: /usr/bin/python2.7, Python 2.7.15rc1, python-minimal, 2.7.15~rc1-1
RelatedPackageVersions:
 dpkg 1.19.0.5ubuntu2
 apt 1.6.3ubuntu0.1
SourcePackage: docker.io
Title: package docker.io 17.12.1-0ubuntu1 failed to install/upgrade: installed docker.io package post-installation script subprocess returned error exit status 1
UpgradeStatus: Upgraded to bionic on 2018-06-01 (115 days ago)

[Steve Beattie (sbeattie)]

Thanks for taking the time to report this bug and helping to make Ubuntu better. We appreciate the difficulties you are facing, but this appears to be a "regular" (non-security) bug. I have unmarked it as a security issue since this bug does not show evidence of allowing attackers to cross privilege boundaries nor directly cause loss of data/privacy. Please feel free to report any other bugs you may find.

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make this software better. This particular crash has already been reported and is a duplicate of bug #1792500, so is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.

[Steve Beattie (sbeattie)]

This looks to be the issue (from DpkgTerminal.log)

 Setting up docker.io (17.12.1-0ubuntu1) ...
 addgroup: The group `docker' already exists and is not a system group. Exiting.
 dpkg: error processing package docker.io (--configure):
  installed docker.io package post-installation script subprocess returned error exit status 1