In practice, what is the difference between running docker -dit and docker run -d?

Question

I used docker run -it to run containers interactively and docker run -d to run them in the background. These two options seemed exceptional. However, I have now noticed that docker run -dit quite common. So what is the difference? When is -it really needed with -d ?

Answer 1

Yes, sometimes you need to include -it even you -d

• If ENTRYPOINT is bash or sh

  docker run -d ubuntu:14.04 will be stopped immediately because bash cannot find any pseudo-terminal to be allocated. You must specify -it so that bash or sh can be assigned to a pseudo-terminal.

   docker run -itd ubuntu:14.04 

• If you want to use nano with any container in the future, you need to specify -it when starting the image. Otherwise, you will get an error. For instance,

   docker run --name mongodb -d mongo docker exec -it mongodb bash apt-get update apt-get install nano nano somefile 

  An error will occur

  Error opening terminal: unknown.