Dockerfile Order of Execution

This lesson focuses on the order that instructions are executed in when building an image. Some instructions may have unintended consequences that can cause your build to fail.

Step 1: Setup your environment:

mkdir centos-conf

cd centos-conf

Step 2: Create the Dockerfile:

vi Dockerfile

Step 3: Creates a CentOS image that uses cloud_user as a non-privileged user

Dockerfile contents:

FROM centos:latest
RUN mkdir -p ~/new-dir1
RUN useradd -ms /bin/bash cloud_user
USER cloud_user
RUN mkdir -p ~/new-dir2
RUN mkdir -p /etc/myconf
RUN echo "Some config data" >> /etc/myconf/my.conf

Step 4: Build the new image:

docker image build -t centos7/myconf:v1 .