installing Docker community edition fails with missing docker-ce package

Question

I'm using Hera and would like to install Docker. I followed the install instructions

https://docs.docker.com/install/linux/docker-ce/ubuntu/

starting at Install using the repository. I'm getting stuck at point two of INSTALL DOCKER ENGINE - COMMUNITY. When running

$ sudo apt-get install docker-ce docker-ce-cli containerd.io

I get the following error message

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package docker-ce is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'docker-ce' has no installation candidate
E: Unable to locate package docker-ce-cli
E: Unable to locate package containerd.io
E: Couldn't find any package by glob 'containerd.io'
E: Couldn't find any package by regex 'containerd.io'

Maybe the problem is related to this one here

https://askubuntu.com/questions/1030179/package-docker-ce-has-no-installation-candidate-in-18-04

If you would like to see my installation process for reproduction:

https://hatebin.com/fmvfvfysqc

1. How can I solve the problem and get the docker community edition?
2. I installed some dependencies and maybe I will get problems if I install other dependencies now. It would be awesome if you would provide a cleanup if your solution requires different installations :)

Answer 1

The instructions point to adding their repository:

$ sudo add-apt-repository \
   "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
   $(lsb_release -cs) \
   stable"

In elementary OS, lsb_release -cs will output hera, for which that repository does not contain anything.

But, as elementary OS is based on Ubuntu 18.04 Bionic, you can easily replace hera with bionic, like this:

$ sudo add-apt-repository \
   "deb [arch=amd64] https://download.docker.com/linux/ubuntu bionic stable"

So, if you follow the instructions on their site, you'll end up with an incorrect repository in the /etc/apt/sources.list file:

deb [arch=amd64] https://download.docker.com/linux/ubuntu hera stable

To fix this, edit the file and replace hera with bionic.

Run a sudo apt update and make sure it outputs no errors.
Now, sudo apt install docker-ce docker-ce-cli containerd.io runs as expected:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following additional packages will be installed:
  aufs-tools cgroupfs-mount pigz
The following NEW packages will be installed:
  aufs-tools cgroupfs-mount containerd.io docker-ce docker-ce-cli pigz
0 upgraded, 6 newly installed, 0 to remove and 17 not upgraded.
Need to get 85,5 MB of archives.
After this operation, 384 MB of additional disk space will be used.
Do you want to continue? [Y/n] 

After the installation completes, running docker -v: Docker version 19.03.5, build 633a0ea838

They do state this in the instructions:

Answer 2

Have you tried installing it with a downloaded .deb installer? It seems that the cli file is sometimes inaccessible due to lack of support for a particular OS.

Or have you tried using: sudo apt install docker.io