A Dockerfile is a script on how to build a Docker image.These instructions are, in fact, a group of commands executed automatically in the Docker environment.
How to Create a Dockerfile
The first thing you need to do is to create a directory.
3.Open the file with a text editor.
4.After that, add the following content:
FROM ubuntu MAINTAINER sofija RUN apt-get update CMD ["echo", "Hello World"]
FROM – Defines the base of the image you create.
RUN : instructions to execute a command while building an image on top of it.You can have more than one instruction in a Dockerfile.
CMD – There can be only one CMD instruction .Its purpose is to provide defaults for an executing container.
5.Save and exit.
Build a Docker Image with Dockerfile
The basic syntax used to build an image with a Dockerfile is:
docker build [OPTIONS] PATH | URL | -
To build a docker image, you would use:
docker build [location of your dockerfile]
If you are already in the directory where the Dockerfile is located.
docker build .
By adding the -t flag, you can tag the new image with a name.
docker build -t my_first_image .
Once the image is successfully built, you can verify whether it is on the list.
Create a New Container
Launch a new Docker container based on the image you created.
docker run --name test my_first_image