Docker · Lesson 3 of 8

Images & Containers

Pull, run, list and clean up.

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Now let's work with real images. You will pull an image from Docker Hub, run it as a container, look at what is running, read its logs, and clean up afterwards. These few commands are the ones you will use every single day.

Pull and list images

terminal

docker pull nginx:1.27
1.27: Pulling from library/nginx
Status: Downloaded newer image for nginx:1.27
docker images
REPOSITORY    TAG       IMAGE ID       CREATED       SIZE
nginx         1.27      3b25b682ea82   2 weeks ago   192MB
hello-world   latest    d2c94e258dcb   1 year ago    13.3kB

The part after the colon is the tag, usually a version. Always pin a tag instead of relying on latest.

Run a web server in a container

This starts nginx in the background (-d), gives the container a name, and maps port 8080 on your computer to port 80 inside the container (-p). Open http://localhost:8080 and you will see the nginx welcome page.

terminal

docker run -d --name web -p 8080:80 nginx:1.27
7f1e2c9a4b8d3e6f...
docker ps
CONTAINER ID   IMAGE        STATUS         PORTS                  NAMES
7f1e2c9a4b8d   nginx:1.27   Up 5 seconds   0.0.0.0:8080->80/tcp   web
curl -s localhost:8080 | head -4
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>

Look inside

terminal

docker logs web
172.17.0.1 - - "GET / HTTP/1.1" 200 615 "-" "curl/8.7.1"
docker exec -it web sh -c "nginx -v"
nginx version: nginx/1.27.2

Command	What it does
docker ps	list running containers (add -a for stopped ones)
docker logs NAME	show what the container printed
docker exec -it NAME sh	open a shell inside a running container
docker stop NAME	stop it gracefully
docker rm NAME	delete a stopped container
docker rmi IMAGE	delete an image

Clean up

terminal

docker stop web
web
docker rm web
web
docker system df
TYPE            TOTAL     ACTIVE    SIZE
Images          2         0         192MB

docker system prune removes stopped containers, unused networks and dangling images in one go.

Try it yourself

✍️ Exercise: Run your own Redis

Start the official redis:7 image in the background with the name cache, check it is running, then stop and remove it.

Show hint

docker run -d --name ..., then docker ps

Show solution

terminalbash

docker run -d --name cache redis:7
docker ps
docker stop cache
docker rm cache

Summary

Key takeaways

docker pull downloads, docker run starts a container
-d runs in the background, -p maps ports
ps, logs, exec, stop and rm manage containers

Next up: Your First Dockerfile — package your own app

❮ Install & Explore Docker Desktop Your First Dockerfile ❯