Docker Setup and Your First Container

01What Is Docker and What Is It Used For?

Docker is a platform that packages an application with everything it needs and runs it in isolated environments called containers. The application, its libraries and its settings are bundled into a single image; this image behaves the same wherever it is run.

In practice this means the "it worked on my machine" problem largely goes away. The developer's laptop, the test server and the production server all use the same image. A new team member can also bring the project up with a single command instead of hours of setup.

Containers are similar to virtual machines but much lighter. Each one does not carry its own operating system; it shares the host's kernel, so it starts in seconds and uses fewer resources.

02Requirements Before Installing

Docker Desktop runs a small virtual environment in the background, so your computer's virtualization support must be turned on. It is on by default on most new computers; if not, you need to enable the Intel VT-x or AMD-V option in the BIOS/UEFI settings.

On Windows, Docker Desktop runs Linux containers on WSL 2. If WSL is not installed, install it first; we described the steps in detail in our WSL installation guide.

• Memory: If several containers will run at the same time, at least 8 GB of RAM gives comfortable working room.
• Disk space: Images accumulate over time; set aside a few tens of GB of free space.
• License: Docker Desktop is free for personal use, education and small businesses below a certain size; larger organizations need a paid subscription. Check the current terms at docker.com.

wsl --install

# After installation, restart the computer, then check
wsl --status

03Docker Desktop on Windows and macOS

Docker Desktop offers Docker Engine, the command-line tool, Docker Compose and a visual management dashboard in a single package. Download the installer from the official site and install it with the default settings.

During installation on Windows, make sure the Use WSL 2 instead of Hyper-V option is checked. On macOS, choose the version that matches your processor: Apple Silicon (M series) or Intel. Start the app after installation; once the whale icon in the menu bar or taskbar settles, Docker is ready.

winget install -e --id Docker.DockerDesktop

04Installing Docker Engine on Linux

On Linux, Docker runs directly as Docker Engine without Docker Desktop; this is also the standard method for servers. The most reliable path is to follow the distribution-specific repository setup in the official documentation. For development machines, Docker's official convenience script does the same job in one go.

If you add your user to the docker group after installation, you don't need to put sudo in front of every command. Because this group grants near-root privileges, add only users you trust.

curl -fsSL https://get.docker.com -o get-docker.sh
sudo sh get-docker.sh

# To use without sudo
sudo usermod -aG docker $USER
newgrp docker

# Start the service at boot
sudo systemctl enable --now docker

05Verifying the Installation

The verification commands are the same whichever operating system you use. The hello-world image is downloaded from Docker Hub, run, prints an explanation to the screen and exits. If you see this output, the client, the engine and the image download chain are all working properly.

docker --version
docker compose version
docker run hello-world

06Running Your First Container

Let's continue with a real example: start nginx, a lightweight web server, as a container and open it in the browser. The -d flag runs the container in the background, and -p 8080:80 maps port 8080 on your computer to port 80 in the container.

After running the command, open http://localhost:8080 in the browser; you should see the nginx welcome page. The other commands below let you monitor the container, get inside it and clean it up.

docker run -d -p 8080:80 --name web nginx

# Running containers
docker ps

# Follow the logs
docker logs web

# Open a shell inside the container
docker exec -it web sh

# Durdur ve sil
docker stop web
docker rm web

# Downloaded images
docker images

Serving your own files

To mount HTML files from a folder into the container, use a bind mount. The command below mounts your current folder read-only to nginx's web root; when you edit the file and refresh the page, you see the change immediately.

docker run -d -p 8080:80 -v "$(pwd)":/usr/share/nginx/html:ro --name site nginx

Building your own image

To turn a Node.js application into an image, add a file named Dockerfile to the project root. Copying the package files and installing dependencies first prevents that layer from being rebuilt when the code changes and speeds up the build.

FROM node:lts-alpine
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
EXPOSE 3000
CMD ["npm", "start"]

docker build -t uygulamam .
docker run -d -p 3000:3000 uygulamam

07Multiple Services with Docker Compose

Real projects usually consist of several parts: a web server, a database, maybe a cache. Instead of starting each one with separate docker run commands, you define them all in a single compose.yaml file with Docker Compose.

The example below starts an nginx web server and a MariaDB database together. Because the database files are kept in a named volume, the data survives even if the container is deleted. The version line seen in older examples is no longer required.

services:
  web:
    image: nginx:alpine
    ports:
      - "8080:80"
    volumes:
      - ./site:/usr/share/nginx/html:ro
    depends_on:
      - db

  db:
    image: mariadb:lts
    environment:
      MARIADB_ROOT_PASSWORD: degistirin
      MARIADB_DATABASE: uygulama
    volumes:
      - db-veri:/var/lib/mysql

volumes:
  db-veri:

docker compose up -d
docker compose ps
docker compose logs -f
docker compose down

# Volume'larla birlikte sil (veriler gider)
docker compose down -v

08Common Errors and Fixes

Problems encountered during a Docker installation are mostly about virtualization, permissions and port conflicts. If images and stopped containers fill the disk over time, docker system prune cleans up unused resources; the command asks for confirmation before deleting.

• WSL 2 / virtualization error: Enable virtualization in the BIOS, update WSL with wsl --update and restart the computer.
• port is already allocated: The port you chose is used by another application. Choose a different port such as -p 8081:80 or close the conflicting application.
• permission denied ... docker.sock: On Linux, your user is not in the docker group; after running usermod, log out and back in.
• Cannot connect to the Docker daemon: Docker Desktop is closed or, on Linux, the service is not running; start it with sudo systemctl start docker.
• Image architecture warning on Mac: Some images are published only for x86. If possible, choose a tag with ARM support.

09What Does Docker Bring to Web Projects?

Docker makes the development, test and production environments of a web project identical. Running a project with PHP and a database in containers instead of single-machine packages like a XAMPP installation reduces surprises caused by version differences. To manage PHP dependencies inside a container, see also our Composer installation guide.

Reproducible environments make it easier for speed and performance improvements to give the same result in production. This consistency also matters for integrated solutions where multiple systems work together and for a growing e-commerce platform.

For other container and server content, take a look at our docker tag page.