What I Did Here
After installing Docker, I wanted to run an actual Ubuntu container — not just hello-world. The steps inside this post are the same on Arch Linux and Ubuntu hosts. Only the Docker installation differs — see Docker on Arch Linux and Ubuntu for that part.
Arch Linux (host)
Make sure Docker is installed and running on your Arch machine first:
sudo pacman -S docker
sudo systemctl enable --now docker
systemctl status docker
Pull the Ubuntu image
sudo docker pull ubuntu
Create and enter a container
sudo docker run --name my-container -it ubuntu
What those flags mean:
-i— keep input open (interactive)-t— give me a terminal inside the container--name my-container— name it so I can find it later
Your shell prompt changes — you are inside the container now.
Update packages inside the container
You are root inside the container, so no sudo:
apt update
apt upgrade -y
Useful commands (from the Arch host)
Run these from your normal Arch terminal, not inside the container:
# List running containers
sudo docker ps
# List all containers (including stopped)
sudo docker ps -a
# Stop the container
sudo docker stop my-container
# Start it again
sudo docker start my-container
# Re-enter a running container
sudo docker exec -it my-container bash
Ubuntu (host)
Make sure Docker is installed and running on your Ubuntu machine first:
sudo apt update
sudo apt install docker.io
sudo systemctl start docker
sudo systemctl enable docker
systemctl status docker
Pull the Ubuntu image
sudo docker pull ubuntu
Create and enter a container
sudo docker run --name my-container -it ubuntu
Same flags as above — after this, you are inside the container.
Update packages inside the container
apt update
apt upgrade -y
Useful commands (from the Ubuntu host)
# List running containers
sudo docker ps
# List all containers (including stopped)
sudo docker ps -a
# Stop the container
sudo docker stop my-container
# Start it again
sudo docker start my-container
# Re-enter a running container
sudo docker exec -it my-container bash
What I Learned
Docker containers are temporary by default — remove one and the changes inside are gone unless you commit it to a new image or use volumes. For learning though, docker run -it ubuntu on either Arch or Ubuntu is the simplest way to get started.
The container itself runs Ubuntu Linux regardless of whether your host is Arch or Ubuntu — that is the whole point of containers.