Run a container

Now that you have an image, you can launch a container to run your program.

docker container run --rm hello

• Output

Hello, world!

The --rm option tells Docker to remove the container once the process running in it terminates. It’s generally a good idea to clean up resources when no longer needed.

One reason not to automatically remove a container when the running process terminates is to inspect the logs after.

docker container run --name helloctr hello

You’ll see the same the output as before. This time we gave the container a name using the --name option to make it easy to refer to it. You can inspect everything the process wrote to stdout and stderr with the docker logs command.

docker container logs helloctr

• Output

Hello, world!

The logs show the same output that was printed to the terminal.

Even though the process exited and the container is no longer usable, you can see that it still exists with the docker container ls command.

docker container ls --all

• Output

CONTAINER ID   IMAGE  COMMAND       CREATED          STATUS                      PORTS      NAMES
c038996a5e75   hello  "/hello.sh"   20 seconds ago   Exited (0) 18 seconds ago              helloctr

The --all option was needed to show containers that have exited.

You can remove the container with the docker container rm command.

docker container rm helloctr

• Output

helloctr

The output indicates the name of the container that was removed.

The program accepts a name argument. You can supply arguments to the docker run command when you run a container.

docker container run --rm hello Docker

• Output

Hello, Docker!

docker container run   =>  docker run
docker container logs  =>  docker logs
docker container ls    =>  docker ps
docker container rm    =>  docker rm