Docker container exits as soon as I start it

Question

When I run or start a Docker container, it will not stay running. Docker start will just return the name of whatever container I gave it, but wont actually do anything.

Docker run (ex $ docker run -p 8080:80 --name hello -d hello-world) will create it but it will exit immediately.

If I run docker ps after one of these, it will show nothing listed as currently running. If I run docker ps -a, it will show all of my containers and show the one that I just attempted to run having exited a few seconds ago.

Is this common and how do I get my containers to stay running? I am trying to learn how to use Docker and it has been one of the worst experiences. Thank you for any help or suggestions.

Answer 1

A docker container exits when its main process finishes. The hello-world main process just prints some text and exits, so container exits too.

You can run this command straightly to see it's text:

docker run hello-world

If you want a running container, maybe you can try a nginx demo:

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

then you can visit http://localhost:8080 using your web browser.