Pulling images, running containers, mounting volumes, and serving a website with httpd.

“It works on my laptop” - Now make it work in a container

Dev vs Production - When your code hits someone else's machine

This continues from Getting Started with Docker. Docker should already be installed and running.

I ran docker run nginx once. It worked. I closed the laptop. The next day: “where’s my site?” Container was gone. I hadn’t realized docker run creates a new container each time and the old one stops when you close the session. Volumes and restart policies exist for a reason. Learn them before you need them.

Prerequisites

Git is needed to clone example web content later.

sudo apt-get update && sudo apt-get install git -y
git --version

Pull and Run an Image

Docker Hub has pre-built images for most common services. Start there. Don’t build from scratch unless you have to. “Your scientists were so preoccupied with whether they could, they didn’t stop to think if they should.” - Jurassic Park. Use existing images. Build custom only when necessary. And pin your tags.

“Pinning image tags matters. :latest is a time bomb. Use httpd:2.4 and sleep better.” - Container registry hygiene

docker pull httpd:latest

Run it. Map port 8080 on your host to port 80 in the container:

docker run --name httpd -p 8080:80 -d httpd:latest

Flags explained:

  • -p 8080:80 - Your browser hits localhost:8080, container sees port 80
  • -d - Detached mode (runs in background, doesn’t block your terminal)
  • --name httpd - Give it a name instead of a random ID. You’ll thank yourself when you have 15 containers running.

Verify the container is running:

docker ps

CONTAINER ID   IMAGE          COMMAND              CREATED          STATUS          PORTS                                   NAMES
88efc101f162   httpd:latest   "httpd-foreground"   22 seconds ago   Up 22 seconds   0.0.0.0:8080->80/tcp, :::8080->80/tcp   httpd
💡 Tip

Add --rm to docker run to auto-remove the container when it stops. Prevents orphaned containers from piling up: docker run --rm --name httpd -p 8080:80 -d httpd:latest.

This container has no custom content yet. Stop and remove it:

docker stop httpd && docker rm httpd

Confirm removal:

docker ps -a

CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES

Serve a Website with a Volume Mount

Clone a sample web repository:

sudo git clone https://github.com/YOUR-USERNAME/forty-html5up /opt/forty-html5up

Run a new container with the cloned content mounted into Apache’s document root:

docker run --name httpd -p 8080:80 -v /opt/forty-html5up:/usr/local/apache2/htdocs:ro -d httpd:latest

The -v flag bind-mounts a host directory into the container. :ro makes it read-only inside the container. Apache serves whatever lands in /usr/local/apache2/htdocs/.

💡 Tip

If the container starts but the page doesn’t load, check docker logs httpd for Apache errors. Common issue: file permissions on the mounted directory prevent Apache from reading the content.

Open http://<docker-host-ip>:8080 in a browser to verify.

docker-image-web-test

“Stateful containers are like houseplants: they need care, feeding, and you’ll be sad when they die.” - Container Orchestration Lesson

💡 Tip

Bind mounts (-v /host/path:/container/path) are great for development, but they couple the container to the host filesystem. For data you want Docker to manage (databases, app state), use named volumes instead:

docker volume create my-data
docker run -d --name httpd -v my-data:/usr/local/apache2/htdocs httpd:latest

Named volumes survive container removal, are portable across hosts with docker volume commands, and don’t depend on a specific host directory existing.

What’s Next

You can pull, run, and mount volumes. Next: how Docker image layering works and building custom images from running containers.

References