A running instance of an image is called a container. Docker launches them using the Docker images as read-only templates. If you start an image, you have a running container of this image. Naturally, you can have many running containers of the same image. In fact, we will do it very often a little bit later, using Kubernetes.
To run a container, we use the docker run command:
docker run [OPTIONS] IMAGE [COMMAND] [ARG...]
There are a lot of run command options and switches that can be used; we will get to know them later on. Some of the options include the network configuration, for example (we will explain Docker's networking concepts in Chapter 2, Networking and Persistent Storage). Others, the same as the -it (from interactive), ...