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How to Install Docker on Ubuntu 22.04, 24.04 and 26.04

2 min readUnixHost team
How to Install Docker on Ubuntu 22.04, 24.04 and 26.04

Docker packages an application together with its dependencies into a container that runs the same way on any server. Below is how to install the current version on Ubuntu from Docker’s official repository, plus the settings worth applying right away.

Why not the package from the Ubuntu repository

Ubuntu has its own docker.io package, but it lags behind. Docker’s official repository provides a current engine and the Compose and Buildx plugins.

Step 1. Remove old packages

sudo apt remove docker.io docker-doc docker-compose podman-docker containerd runc

If the packages are not installed, the command simply says so.

Step 2. Add the Docker repository

sudo apt update
sudo apt install -y ca-certificates curl
sudo install -m 0755 -d /etc/apt/keyrings
sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
sudo chmod a+r /etc/apt/keyrings/docker.asc
echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

Step 3. Install Docker

sudo apt update
sudo apt install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

The service starts automatically and is enabled at boot. Check it:

sudo systemctl status docker
sudo docker run --rm hello-world

Step 4. Run without sudo

sudo usermod -aG docker $USER

Log out and back in. Remember: a member of the docker group effectively has root access.

Step 5. Limit log size

By default container logs grow without limit and eventually fill the disk. Create /etc/docker/daemon.json:

{
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "10m",
    "max-file": "3"
  }
}

Restart the service:

sudo systemctl restart docker

The setting applies to containers created after the restart.

Essential commands

Command What it does
docker ps list running containers (-a for all)
docker images list downloaded images
docker run -d --name web -p 8080:80 nginx start a container in the background
docker logs -f web follow a container’s log
docker exec -it web sh open a shell inside a container
docker stop web / docker start web stop and start
docker rm web remove a container
docker compose up -d start the services from docker-compose.yml

Docker and the firewall

Docker manages packet filter rules itself, so a port published with -p 8080:80 is reachable from the internet even if UFW does not allow it. To keep a service local, publish the port on the loopback address:

docker run -d -p 127.0.0.1:8080:80 nginx

Cleaning up disk space

See how much space Docker uses:

docker system df

Remove stopped containers, unused networks and untagged images:

docker system prune

With -a, all images not used by a container are removed; with --volumes, unused volumes too. Be careful with volumes: that is where data lives.

Updating and removing

Docker updates together with the system:

sudo apt update && sudo apt upgrade

Full removal including images, containers and volumes:

sudo apt purge docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
sudo rm -rf /var/lib/docker /var/lib/containerd

Next steps

  • Portainer — a web interface for managing containers.
  • Dozzle — read logs in the browser.
  • Watchtower — automatic container updates.

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