Editor: RHSCL is Red Hat Software Collections, a subscription-based suite of tools available to Red Hat’s customers that make it possible to build and install multiple versions of the same software components on your system. A future article will show how to do the same on Fedora.
New RHSCL-based Docker images that are now in beta let you easily build your own application containers even without writing any Dockerfiles. Here is an example of a Ruby on Rails application built with the Ruby 2.2 image using the PostgreSQL 9.4 image as a database backend.
For building the application image we will use a tool called source-to-image (s2i, formally sti) which is a program that can build your application image on top of s2i images. For example the latest version of OpenShift uses s2i images to run your applications as well and you can use them with source-to-image to containerize your own applications locally.
In this blog post I assume you are running RHEL 7 and you have the latest Docker from rhel-7-server-extras-rpms channel and that you enabled rhel-server-rhscl-7-beta-rpms channel for getting the source-to-image tool.
If you did not, run:
# Uncommented lines are commands you must run
# 1. Add Extras repo
sudo subscription-manager repos --enable=rhel-7-server-extras-rpms
# 2. Enable testing repos
sudo subscription-manager repos --enable=rhel-server-rhscl-7-beta-rpms
# 3. Install the image
sudo yum install -y docker source-to-image
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