docker - How to pass arguments to a Dockerfile?

Question

I am using RUN instruction within a Dockerfile to install a rpm

RUN yum -y install samplerpm-2.3

However, I want to pass the value "2.3" as an argument. My RUN instruction should look something like:

RUN yum -y install samplerpm-$arg

where $arg=2.3

Answer 1

You are looking for --build-arg and the ARG instruction. These are new as of Docker 1.9.

Check out this document for reference. This will allow you to add ARG arg to the Dockerfile and then build with

docker build --build-arg arg=2.3 .