FROM
The base image for building a new image. This command must be on top of the dockerfile. MAINTAINER
Optional, it contains the name of the maintainer of the image. RUN
Used to execute a command during the build process of the docker image. ADD
Copy a file from the host machine to the new docker image. There is an option to use a URL for the file, docker will then download that file to the destination directory. ENV
Define an environment variable. CMD
Used for executing commands when we build a new container from the docker image. ENTRYPOINT
Define the default command that will be executed when the container is running. WORKDIR
This is directive for CMD command to be executed. USER
Set the user or UID for the container created with the image. VOLUME
Enable access/linked directory between the container and the host machine. Now let's start to create our first dockerfile.

FROM java:8-jdk-alpine
COPY ./target/app.jar /usr/app/
WORKDIR /usr/app
RUN sh -c 'touch app.jar'
ENTRYPOINT ["java","-jar”,”app.jar"]