初めてのコンテナを実行する

Time to run real containers. You'll launch apps from images, interact with them, and learn the commands that manage their lifecycle.

docker run is your launch button: it checks for the image (pulling if needed), creates a container from it, and starts it — all in one command.

Run the simplest container there is: hello-world. It prints a message and exits. Try it below.

Behind that hello-world run, Docker pulled the image, created a container, ran its command, printed the greeting, then stopped. A clean first cycle.

To work inside a container, combine the -it flags: -i keeps STDIN open and -t gives you a terminal, so you can type commands inside it.

Spin up minimal Alpine Linux and drop into its shell to run real Linux commands. Type exit to leave the container.

To keep a container running without locking your terminal, use detached mode with the -d flag. Docker prints the container ID and hands control back.

Containers are isolated, so reach a service inside one with port mapping. The -p flag maps a host port to a container port: host:container.

Combine detached mode and port mapping to run Nginx in the background, mapping your host's 8080 to the container's port 80. See the command below.

Clean up when you're done: docker stop halts a running container and docker rm removes a stopped one. Grab the ID from docker ps first.

You want to run a container and immediately get a shell inside it to execute commands. Which option would you use with docker run?

Recap: docker run launches containers; -it gives a shell, -d runs detached, -p maps ports — plus stop and rm to clean up afterward.