Ubuntu – Is missing cockpit-docker no longer in the 20.04 repository

It appears that docker-ce is hanging on service start:

 \_ apt install docker-ce
     \_ /usr/bin/dpkg --status-fd 64 --configure --pending
         \_ /bin/sh /var/lib/dpkg/info/docker-ce.postinst configure
             \_ /bin/sh /usr/sbin/invoke-rc.d docker start
                 \_ systemctl start docker.service
                     \_ /bin/systemd-tty-ask-password-agent --watch

Killing systemctl start docker.service process should be enough:

sudo kill -9 $(ps aux | grep "systemctl start docker.service" | head -n 1 | awk '{print $2}')

check systemd jobs:

sudo systemctl list-jobs
    JOB UNIT           TYPE  STATE  
2831057 docker.service start running

if any docker job is running, kill it:

sudo systemctl kill docker.service

Make sure to verify that you don't have any overrides defined:

/etc/systemd/system/docker.service.d/

e.g. overriding command to (used in 17.03 release):

ExecStart=/usr/bin/docker daemon

instead of /usr/bin/dockerd. Before continuing be sure to kill any remaining docker process:

ps aux | grep "[d]ockerd"

stop remaining Docker daemon process (if there's any):

sudo kill -9 $(ps aux | grep "[d]ockerd" | head -n 1 | awk '{print $2}')

If you're upgrading from previous docker version (docker.io, docker-engine etc.) or just changing underlying file storage, it's safer to delete all docker data before installing new version.

sudo rm -rf /var/lib/docker
sudo apt install docker-ce

To fix broken installation, just run sudo dpkg --configure -a and docker.service should start.

TL;DR

You have to enable xenial-updates and xenial-security in your /etc/apt/sources.list or on Updates tab of Software & Updates (software-properties-gtk).

It seems that you incorrectly understand the pool folder structure. It contains all packages for all releases.

You should go to https://packages.ubuntu.com and run search for chromium-browser package amd64 to determine correct versions for your current release.

Then you will get the following for xenial and xenial-updates:

xenial (16.04LTS) (web): Chromium web browser, open-source version of Chrome [universe]
78.0.3904.108-0ubuntu0.16.04.1 [security]: amd64
xenial-updates (web): Chromium web browser, open-source version of Chrome [universe] 78.0.3904.108-0ubuntu0.16.04.1: amd64

So you can get the latest possible package version from universe pocket:

78.0.3904.108-0ubuntu0.16.04.1: amd64

On my fully updated system the output is the following:

$ apt-cache policy chromium-browser chromium-browser: Installed: 78.0.3904.108-0ubuntu0.16.04.1 Candidate: 78.0.3904.108-0ubuntu0.16.04.1 Version table: *** 78.0.3904.108-0ubuntu0.16.04.1 500 500 http://archive.ubuntu.com/ubuntu xenial-updates/universe amd64 Packages 500 http://archive.ubuntu.com/ubuntu xenial-security/universe amd64 Packages 100 /var/lib/dpkg/status 49.0.2623.108-0ubuntu1.1233 500 500 http://archive.ubuntu.com/ubuntu xenial/universe amd64 Packages

In your particular case it seems that xenial-updates is missed in your /etc/apt/sources.list file. You need to re-enable it from terminal or by visiting Updates tab of Software & Updates (software-properties-gtk) .

Also I need to note that current Ubuntu 16.04 LTS version is 16.04.6 LTS.
So really you need to enable xenial-updates, xenial-security, then update package lists with sudo apt-get update and install all newest dependencies with sudo apt-get dist-upgrade. This will solve many security- and update- related problems.