Docker on VPS: Complete Beginner's Guide to Container Deployment in 2025

Docker has revolutionized how we deploy and manage applications, transforming complex multi-server architectures into portable, reproducible containers. For VPS users, Docker offers a game-changing approach to application deployment—package your application with all its dependencies into containers that run consistently across any environment. Whether you're deploying web applications, databases, microservices, or development environments, Docker simplifies the process while improving reliability and resource efficiency.

This comprehensive beginner's guide demystifies Docker on VPS. We'll start with fundamental concepts, walk through installation and basic operations, and build up to deploying real-world applications. By the end, you'll understand not just how to use Docker, but why it's become the standard for modern application deployment and how it can transform your VPS infrastructure.

Understanding Docker: Containers vs. Virtual Machines

Before diving into technical details, let's understand what Docker actually is and why it matters. Docker is a containerization platform that packages applications and their dependencies into standardized units called containers. Unlike virtual machines that virtualize hardware and run entire operating systems, containers share the host system's kernel while maintaining isolated user spaces.

Think of containers as lightweight, portable application packages. A container includes your application code, runtime environment, system libraries, and dependencies—everything needed to run your application. This "build once, run anywhere" approach eliminates the infamous "it works on my machine" problem that plagues traditional deployment methods.

For VPS users, Docker's efficiency is particularly valuable. Where you might have struggled to run multiple applications on a modest VPS due to resource constraints and dependency conflicts, Docker enables running dozens of containerized services on the same hardware. Each container uses only the resources it needs, and there's no overhead of multiple operating systems consuming your RAM and CPU.

Prerequisites: Preparing Your VPS for Docker

Docker runs on most modern Linux distributions. If you're choosing a distribution specifically for Docker, Ubuntu and Debian are excellent choices with strong Docker support and extensive documentation. AlmaLinux and Rocky Linux also work perfectly with Docker. Check our guide on choosing the right Linux distribution for your VPS if you haven't deployed your server yet.

Minimum VPS requirements for Docker depend on what you plan to run, but as a starting point: 1GB RAM minimum (2GB+ recommended), at least 20GB storage (SSD preferred), and a modern Linux kernel (4.0+). Your VPS should be properly secured before installing Docker—review our VPS security guide to ensure your server is hardened.

Ensure your system is fully updated before proceeding. On Ubuntu/Debian: sudo apt update && sudo apt upgrade -y. On CentOS/AlmaLinux/Rocky: sudo dnf update -y.

Installing Docker on Your VPS

sudo apt install apt-transport-https ca-certificates curl software-properties-common -y
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg

echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

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

sudo systemctl status docker
docker --version

sudo dnf install yum-utils -y

sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

sudo dnf install docker-ce docker-ce-cli containerd.io docker-compose-plugin -y

sudo systemctl start docker
sudo systemctl enable docker

Post-Installation Setup

By default, Docker requires sudo for every command. To allow your user to run Docker commands without sudo, add your user to the docker group:

sudo usermod -aG docker $USER

Log out and back in for this change to take effect. Verify Docker works without sudo:

docker run hello-world

This command downloads a test image and runs it in a container. If you see a "Hello from Docker!" message, your installation is successful and ready for real work.

Docker Fundamentals: Images, Containers, and Registries

Understanding Docker's core concepts is essential before deploying applications. Let's break down the key terminology.

Docker Images

A Docker image is a read-only template containing application code, runtime, libraries, and dependencies. Think of an image as a snapshot or blueprint for creating containers. Images are built from Dockerfiles—text files containing instructions for assembling the image. You can create your own images or use pre-built images from Docker Hub, a public registry hosting thousands of official and community images.

Docker Containers

A container is a running instance of an image. When you execute docker run, Docker creates a container from an image, starts it, and runs the specified application inside. Containers are ephemeral—when stopped, any changes made inside are lost unless you've configured persistent storage. You can run multiple containers from the same image, each operating independently.

Docker Registries

Docker registries store and distribute images. Docker Hub is the default public registry, but you can use private registries for proprietary applications. When you run docker pull nginx, Docker downloads the nginx image from Docker Hub to your local machine. You can also push your own images to registries for distribution or backup.

Your First Container: Running a Web Server

Let's deploy a practical example—an Nginx web server—to understand Docker's workflow. This single command downloads the Nginx image and starts a container:

docker run -d -p 80:80 --name my-nginx nginx

Let's break down what's happening:

• docker run - Creates and starts a container
• -d - Runs the container in detached mode (background)
• -p 80:80 - Maps port 80 on your VPS to port 80 in the container
• --name my-nginx - Assigns a friendly name to the container
• nginx - The image to use (downloaded from Docker Hub if not present locally)

Visit your VPS's IP address in a browser, and you'll see the Nginx welcome page. Congratulations—you've deployed your first containerized application! This Nginx server is completely isolated from your host system. You can run multiple Nginx containers with different configurations, and they won't interfere with each other.

Essential Docker Commands Every Beginner Should Know

docker ps

docker ps -a

docker stop my-nginx

docker start my-nginx

docker restart my-nginx

docker rm my-nginx

docker logs my-nginx

docker exec -it my-nginx bash

docker images

docker pull ubuntu:22.04

docker rmi nginx

docker system prune -a

These commands form the foundation of Docker operations. Practice with different containers to build familiarity. The docker exec command is particularly useful for troubleshooting—you can access a running container's shell to inspect files, check processes, or debug issues.

Deploying Real Applications with Docker Compose

While docker run works for single containers, real applications often require multiple connected services—a web application, database, cache, and reverse proxy. Docker Compose orchestrates multi-container applications through a simple YAML configuration file.

Docker Compose is included with modern Docker installations. Create a file named docker-compose.yml:

version: '3.8'

services:
  web:
    image: nginx:latest
    ports:
      - "80:80"
    volumes:
      - ./html:/usr/share/nginx/html
    restart: unless-stopped

  app:
    image: php:8.2-fpm
    volumes:
      - ./html:/var/www/html
    restart: unless-stopped

  db:
    image: mysql:8.0
    environment:
      MYSQL_ROOT_PASSWORD: secure_password
      MYSQL_DATABASE: myapp
    volumes:
      - db_data:/var/lib/mysql
    restart: unless-stopped

volumes:
  db_data:

This configuration defines a complete web application stack with Nginx, PHP-FPM, and MySQL. Start everything with a single command:

docker compose up -d

Docker Compose creates networks for service communication, manages volumes for persistent data, and ensures services start in the correct order. Stop the entire stack with docker compose down. This approach dramatically simplifies managing complex applications—what might have taken hours of manual configuration becomes a declarative YAML file you can version control and share.

Data Persistence: Volumes and Bind Mounts

By default, data inside containers is ephemeral—it disappears when the container is removed. For applications that need persistent data (databases, uploaded files, configuration), Docker provides volumes and bind mounts.

Volumes

Volumes are Docker-managed storage that persists independently of containers. Create a volume:

docker volume create my-data

Use it in a container:

docker run -d -v my-data:/data ubuntu

Data written to /data inside the container is stored in the volume and survives container removal. Volumes are the recommended approach for database storage and other persistent data needs.

Bind Mounts

Bind mounts map a directory on your VPS directly into a container. This is useful for development or when you need direct access to container data from your host. Our earlier Docker Compose example used bind mounts with ./html:/usr/share/nginx/html—files in your html directory are immediately accessible inside the container.

Networking: Connecting Containers

Docker automatically creates networks that allow containers to communicate. When you use Docker Compose, all services in the compose file share a network and can reach each other using service names as hostnames. The PHP container can connect to the MySQL database using db:3306 as the connection string—Docker's internal DNS resolves service names to container IPs.

For manually created containers, create custom networks:

docker network create my-network
docker run -d --network my-network --name web nginx
docker run -d --network my-network --name app php:8.2-fpm

Containers on the same network can communicate, while containers on different networks are isolated—providing both connectivity and security through network segmentation.

Security Best Practices for Docker on VPS

While Docker provides isolation, you must follow security best practices to keep your containerized infrastructure secure.

• Don't run containers as root: Use the USER directive in Dockerfiles to run processes as non-root users inside containers
• Keep images updated: Regularly pull fresh images to get security patches—docker pull <image> and recreate containers
• Use official images: Prefer official images from Docker Hub over random community images
• Scan for vulnerabilities: Use docker scan <image> to check for known vulnerabilities
• Limit container resources: Use --memory and --cpus flags to prevent containers from consuming all VPS resources
• Secure the Docker daemon: Follow our VPS security guide and ensure Docker's socket is properly protected
• Use secrets for sensitive data: Never hardcode passwords in Dockerfiles or compose files—use Docker secrets or environment variables

Remember that containers share your VPS's kernel. While isolated, a kernel vulnerability could potentially affect all containers. Keep your VPS operating system updated alongside your container images.

Performance Optimization and Resource Management

Docker is efficient, but you should still monitor and optimize resource usage, especially on smaller VPS plans. Use docker stats to view real-time resource consumption of running containers:

docker stats

This shows CPU, memory, network, and disk I/O for each container. If a container consumes excessive resources, investigate why—perhaps it needs tuning, more resources, or has a bug.

Set resource limits to prevent runaway containers from affecting other services:

docker run -d --memory="512m" --cpus="0.5" nginx

This limits the container to 512MB RAM and half a CPU core. In Docker Compose, add resource limits under each service's configuration. Proper resource management ensures stable performance across all your containerized applications.

Real-World Example: Deploying WordPress with Docker

Let's deploy a production-ready WordPress site using Docker Compose. Create docker-compose.yml:

version: '3.8'

services:
  wordpress:
    image: wordpress:latest
    ports:
      - "80:80"
    environment:
      WORDPRESS_DB_HOST: db
      WORDPRESS_DB_USER: wordpress
      WORDPRESS_DB_PASSWORD: secure_password_here
      WORDPRESS_DB_NAME: wordpress
    volumes:
      - wordpress_data:/var/www/html
    restart: unless-stopped

  db:
    image: mysql:8.0
    environment:
      MYSQL_DATABASE: wordpress
      MYSQL_USER: wordpress
      MYSQL_PASSWORD: secure_password_here
      MYSQL_ROOT_PASSWORD: root_password_here
    volumes:
      - db_data:/var/lib/mysql
    restart: unless-stopped

volumes:
  wordpress_data:
  db_data:

Deploy with docker compose up -d. In minutes, you have a fully functional WordPress site with MySQL database, persistent storage, and automatic restarts. Front this with Nginx as a reverse proxy (see our high-performance web server guide) and add SSL certificates for a production-ready setup.

Backup and Disaster Recovery

Backing up containerized applications involves backing up volumes and configuration files. For volume backups, you can create archives of volume data:

docker run --rm -v my-data:/data -v $(pwd):/backup ubuntu tar czf /backup/my-data-backup.tar.gz /data

This creates a temporary container that mounts your volume and creates a compressed backup in your current directory. Store these backups off-server for disaster recovery.

Your Docker Compose files and Dockerfiles should be version controlled in Git. With these files and volume backups, you can recreate your entire infrastructure from scratch on a new VPS—one of Docker's most powerful benefits for disaster recovery.

Learning Resources and Next Steps

You've now covered Docker fundamentals and deployed real applications. To continue your Docker journey, explore official Docker documentation, experiment with different images from Docker Hub, and try building custom images with Dockerfiles. Practice is key—the more you use Docker, the more intuitive it becomes.

Consider learning Docker networking in depth, exploring Docker Swarm for multi-server orchestration, or diving into Kubernetes for enterprise-scale container management. Each builds on the fundamentals covered here.

Many developers use Docker for local development that mirrors production environments. If you haven't already, explore whether VPS is right for your projects and ensure you've chosen the appropriate Linux distribution for your containerized infrastructure.

Conclusion: Embracing Containerization

Docker transforms how we think about application deployment. What once required complex manual configuration, dependency management, and careful documentation now becomes a reproducible, portable container. For VPS users, Docker unlocks the ability to run multiple isolated applications efficiently, scale rapidly, and maintain consistent environments from development through production.

Start small—containerize one application, get comfortable with the workflow, then expand to more complex deployments. Docker has a learning curve, but the investment pays dividends in deployment simplicity, reliability, and efficiency. The concepts you've learned here—images, containers, volumes, networks, and composition—form the foundation of modern infrastructure.

Your VPS with Docker is now a powerful platform for running virtually any application stack. Whether you're deploying web apps, databases, APIs, or development environments, containers provide the flexibility and isolation you need while maximizing your VPS resources. Welcome to the world of containerization—you've taken the first steps toward modern infrastructure management.