Dockerfile

Question 1

What must be the first command in a Dockerfile? What is the exception?

Answer 1

FROM baseImage

The exception is if an ARG command is used to declare arguments passed to FORM

Question 2

Given the following code:

FROM busybox
ENV FOO=/bar
WORKDIR 

What is the syntax for using FOO as the WORKDIR?

Answer 2

WORKDIR ${FOO}

Question 3

What is the purpose of EXPOSE?

Answer 3

To document which ports are available for binding so you don’t have to look at the application’s source code