Installing Docker on a root server: Debian and Ubuntu

Requirements

• A KVM root server with Debian 12 or Ubuntu 22.04 or 24.04. Container vServers (LXC) are not suitable for Docker.
• At least 2 GB of memory, for several containers 4 GB or more.
• A user with sudo rights and SSH access.
• An up-to-date system: run "apt update" and "apt upgrade" first.

Installation in five steps

• Install dependencies: apt install ca-certificates curl gnupg
• Load the Docker GPG key to /etc/apt/keyrings/docker.gpg and add the Docker package source for your distribution to /etc/apt/sources.list.d/docker.list.
• Update package lists and install: apt install docker-ce docker-ce-cli containerd.io docker-compose-plugin
• Add your user to the group: usermod -aG docker youruser, then log in again.
• Test: docker run hello-world

Docker Compose: several containers as one project

With Compose you describe an application including database, cache and reverse proxy in one file "compose.yaml" and start everything with "docker compose up -d". Create a separate directory per project, then volumes, networks and updates stay cleanly separated.

Security: ports, updates, root

• Only publish ports that must be reachable from outside. "127.0.0.1:8080:80" instead of "8080:80" keeps services local.
• Docker writes its own firewall rules. After installation, check whether your ufw rules still apply.
• Keep images up to date: "docker compose pull" and "docker compose up -d" at regular intervals.
• Include volumes in your backup, containers themselves are replaceable.

Which server for Docker?

For a few services a KVM root server with 4 GB RAM is enough. Databases, build pipelines or many parallel containers benefit from more cores, the EPYC line fits here. If you run an entire stack for a team and want to virtualise yourself, take a dedicated server with Proxmox and Docker VMs inside.