What is this instruction, and why must it be tweaked to work with fish? Before I answer that let me say that too many Linux/Unix users try to be too clever by half, especially the official documentation and how-to instruction writers. But I digress…

What you want to do is to create a one-line text file at /etc/apt/sources.list.d/docker.list that contains this line for this version of Linux Mint:

deb [arch=amd64 signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu noble stable

You’re welcome.

And this is the bit of overly complicated fish script that will accomplish this:

echo \"deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu \$(string split = $(grep UBUNTU_CODENAME /etc/os-release) -f 2) stable" | \sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

All the fish specific magic is on line 3. It’s here we search for the line containing UBUNTU_CODENAME in /etc/os-release, split the line on the equals sign, and then use the second element returned in the string array. You can save yourself some aggravation by just copying the result line and then using sudo to echo that one line to /etc/apt/sources.list.d/docker.list. You still have to do some more work, which is at the official Docker documentation site, in the links below. What you want to focus on is “Install using the apt repository.”

Links

Install Docker Engine on Ubuntu — https://docs.docker.com/engine/install/ubuntu/

Here are the steps to install Docker and the Portainer container that provides your Docker installation with a simple, web-based dashboard.

Update 64-bit Raspbian:

sudo apt update && sudo apt upgrade -y

Install Docker from the Docker website:

curl -sSL https://get.docker.com | sh

Add the pi account to the docker user group so that you can execute docker commands without sudo:

sudo usermod -aG docker pi

Reboot

sudo reboot

Log back in and test Docker by installing and running the following container.

docker run hello-world

The container will run and tell you it was successful with additional information about Docker and its OS.

Hello from Docker!This message shows that your installation appears to be working correctly.To generate this message, Docker took the following steps: 1. The Docker client contacted the Docker daemon. 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.(arm64v8) 3. The Docker daemon created a new container from that image which runs theexecutable that produces the output you are currently reading. 4. The Docker daemon streamed that output to the Docker client, which sent itto your terminal.To try something more ambitious, you can run an Ubuntu container with: $ docker run -it ubuntu bashShare images, automate workflows, and more with a free Docker ID: https://hub.docker.com/For more examples and ideas, visit: https://docs.docker.com/get-started/

To be honest, I haven’t tried the recommendation about running the Ubuntu container, as I don’t know if it there is an ARM Ubuntu container (there is ARM Ubuntu, however) and if it will select the right container if there is such a container.

Install the next two containers. The first is a very simple http container.

docker run -d -p 80:80 hypriot/rpi-busybox-httpd

Navigate to http://localhost with Chromium and you’ll see this:

Now add the dashboard container that implements Portainer for ARM.

docker run -d -p 9000:9000 -v /var/run/docker.sock:/var/run/docker.sock portainer/portainer:arm

Navigate to http://localhost:9000/ and create an admin password for the admin account. Once that is accomplished, you’ll see something very similar to this:

You’ll note that only two containers are listed, not three. That’s because earlier I removed the “Hello World” container. Here’s a detailed listing of the containers.

To manage any of the containers, you select that container’s checkbox. That enables all of the possible action buttons at the top of the page. Finally, here’s a check of the entire system.

The engine overview is a cleaner view of what you can get from the command line. It’s also a validation that the dashboard container is seeing everything it’s supposed to see.

NOTE

If you want any container to restart after a re-boot, then you need to modify the container’s restart policy. Otherwise, on reboot, no containers are running. For example

docker update --restart=always [container ID]

where he container ID can be found with a docker ps from the command line. You can set restart to always from the command line with the docker run command as well.

It’s a limitation to this application I don’t like. I’m looking for something more comprehensive, or else, (shudder) I fork the application and “fix” it myself.

These are early days for me, but I’ve managed to get Docker up and running on my Raspberry Pi 3 (quad core 1GHz ARMv7 (v7l), 1GB DRAM). I’m running Arch Linux. Here’s what ‘cat /proc/version’ shows:

Linux version 4.1.21-1-ARCH (builduser@leming) (gcc version 5.3.0 (GCC) ) #1 SMP Wed Apr 6 19:29:49 MDT 2016

In order to get Docker installed I ran ‘sudo pacman -S docker’ followed by ‘sudo systemctl enable docker’ followed by ‘sudo systemctl start docker’.

I have yet to learn how to create a container, but I have found at least one to download and run within my Raspberry Pi. I executed ‘sudo docker run -d -p 80:80 hypriot/rpi-busybox-httpd’. This starts a little httpd server which can be reached by any local web browser (i.e. inside the home network). For example, using Vivaldi:

You can read more about this particular container here: Getting started with Docker on your Raspberry Pi

Once up and running, there are some simple CLI commands to monitor and control what’s running:

• ‘sudo docker ps’ returns a list of all running containers. The first entry in each line of the listing is the container ID, and it’s used to control it with other commands. If you want to see all containers, running or otherwise, execute ‘sudo docker ps -l’ (lower case L)
• ‘sudo docker stop [containerID]’ stops a container.
• ‘sudo docker start [containerID]’ starts a container. For stop and start remember to use ‘ps -l’ to get the container ID whether it’s running or not.

There is more to come, but for now this is a decent start. Software is installed and from what I can determine by examination the Raspberry Pi 3 is doing a decent job running Docker and at least one container. Not bad for a $35 computer.