Docker & Containers

3 guides

Learn Docker from the ground up — installation, Docker Compose, volumes and networking, reverse proxies, image security, and fixes for the most common Docker errors.

Diagram-style cover showing a Docker container failing to bind a host port already taken by another process

Docker & Containers

How to Fix Docker Error: Port Is Already Allocated

Fix the Docker 'port is already allocated' error: find what's using the port with docker ps, ss, and lsof, then free it or change the mapping.

Sysadmin Desk Jun 13, 2026 8 min read

Terminal-style cover showing apt installing Docker Engine on Ubuntu Server with the official Docker repository configured

Pillar Guide

Docker & Containers

How to Install Docker on Ubuntu Server Step by Step

Install Docker on Ubuntu Server the right way: add the official apt repo and GPG key, install docker-ce plus the Compose plugin, and verify it works.

Sysadmin Desk Jun 6, 2026 9 min read

Diagram-style cover showing one compose.yaml file defining a web container and a database container connected on a shared Docker network

Pillar Guide

Docker & Containers

Docker Compose Beginner Guide: Run Multiple Containers with One File

Learn Docker Compose from scratch: write one YAML file to run multiple containers, with a working WordPress + MySQL example and the core up/down commands.

Sysadmin Desk May 26, 2026 10 min read