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

As of Docker 1.9, You are looking for --build-arg and the ARG instruction.

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 .