What is the function of the 'docker run' command followed by an image name (e.g., 'ubuntu')?

What is the function of the 'docker run' command followed by an image name (e.g., 'ubuntu')?

• A. To pull an image from a registry
• B. To build a new image from a Dockerfile
• C. To remove a container
• D. To start a new container using the specified image

Answer: (D)

Starting a new container from an image is what the docker run command does. When you run docker run with an image name like ubuntu, Docker creates a new container based on that image and then starts it. If the image isn’t already on your machine, Docker will pull it from a registry first, then create and start the container. The container runs the default command defined in the image (or a command you override on the command line) inside its isolated environment with its own filesystem, namespaces, and resource limits. This is different from pulling an image (docker pull), which only fetches the image without creating or starting a container; building a new image from a Dockerfile (docker build) creates a new image, not a container; and removing a container (docker rm) deletes an existing container.

Starting a new container from an image is what the docker run command does. When you run docker run with an image name like ubuntu, Docker creates a new container based on that image and then starts it. If the image isn’t already on your machine, Docker will pull it from a registry first, then create and start the container. The container runs the default command defined in the image (or a command you override on the command line) inside its isolated environment with its own filesystem, namespaces, and resource limits.

This is different from pulling an image (docker pull), which only fetches the image without creating or starting a container; building a new image from a Dockerfile (docker build) creates a new image, not a container; and removing a container (docker rm) deletes an existing container.