How to install Docker on a VPS?

Updated: 11 October 2026 · Applies to: Ubuntu 24.04, Debian 12, AlmaLinux 9 and Rocky Linux 9

Docker runs applications in containers, so each app brings its own dependencies. Install it on a Ucartz VPS with Ubuntu 24.04, Debian 12, AlmaLinux 9 and Rocky Linux 9.

Install Docker Engine (official repository)

Ubuntu 24.04 / Debian 12:

apt install ca-certificates curl
install -m 0755 -d /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
chmod a+r /etc/apt/keyrings/docker.asc
tee /etc/apt/sources.list.d/docker.sources <<EOF
Types: deb
URIs: https://download.docker.com/linux/ubuntu
Suites: $(. /etc/os-release && echo "$VERSION_CODENAME")
Components: stable
Architectures: $(dpkg --print-architecture)
Signed-By: /etc/apt/keyrings/docker.asc
EOF
apt update
apt install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

On Debian, use https://download.docker.com/linux/debian in both the key URL and URIs.

AlmaLinux 9 / Rocky Linux 9:

dnf install dnf-plugins-core
dnf config-manager --add-repo https://download.docker.com/linux/rhel/docker-ce.repo
dnf install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
systemctl enable --now docker

Test with docker run hello-world. Compose is available as docker compose.

First containers

docker run -d --name web -p 80:80 nginx
docker ps
docker logs web
docker stop web && docker rm web

Compose

Describe multi-container apps in compose.yaml and start them with docker compose up -d.

Note: KVM VPS (as used by Ucartz) run Docker without restrictions. Keep images updated with docker compose pull && docker compose up -d.

Why use Docker on a VPS

• Each app runs with its own dependencies, so two apps never conflict (for example two WordPress sites with different PHP versions).
• The same image runs on your laptop and on the server, so what you tested is what you deploy.
• A crashed container does not affect other containers, and --restart unless-stopped starts it again automatically, also after a reboot.
• Moving an app to another server means copying its compose file and volumes.

Everyday commands

docker images                       # downloaded images
docker ps -a                        # all containers, also stopped ones
docker exec -it web sh              # open a shell inside a container
docker logs -f web                  # follow the log
docker volume ls                    # data volumes (back these up)
docker system df                    # disk space used by Docker

Note: Clean up unused images with docker image prune. Be careful with docker system prune --volumes: it deletes volumes that no container uses, including data.

Common problems

• permission denied ... docker.sock: run the command with sudo, or add your user to the docker group and log in again.
• Port is already allocated: another container or service (often Apache or Nginx) already uses that port. Check with ss -tlnp.
• The disk fills up: limit log size in /etc/docker/daemon.json with {"log-driver": "json-file", "log-opts": {"max-size": "10m", "max-file": "3"}} and restart Docker.