// Module included in the following assemblies:
//
// * security/container_security/security-container-content.adoc

[id="security-container-content-universal_{context}"]
= Creating redistributable images with UBI 

To create containerized applications, you typically start with a trusted base
image that offers the components that are usually provided by the operating system.
These include the libraries, utilities, and other features the application
expects to see in the operating system's file system.

Red Hat Universal Base Images (UBI) were created to encourage anyone building their
own containers to start with one that is made entirely from Red Hat Enterprise
Linux rpm packages and other content. These UBI images are updated regularly
to keep up with security patches and free to use and redistribute with
container images built to include your own software. 

Search the
link:https://catalog.redhat.com/software/containers/explore[Red Hat Ecosystem Catalog]
to both find and check the health of different UBI images.
As someone creating secure container images, you might
be interested in these two general types of UBI images:

* **UBI**: There are standard UBI images for RHEL 7 and 8 (`ubi7/ubi` and
`ubi8/ubi`), as well as minimal images based on those systems (`ubi7/ubi-minimal`
and `ubi8/ubi-mimimal`). All of these images are preconfigured to point to free
repositories of {op-system-base} software that you can add to the container images you build,
using standard `yum` and `dnf` commands.
Red Hat encourages people to use these images on other distributions,
such as Fedora and Ubuntu.

* **Red Hat Software Collections**: Search the Red Hat Ecosystem Catalog
for `rhscl/` to find images created to use as base images for specific types
of applications. For example, there are Apache httpd ([x-]`rhscl/httpd-*`),
Python ([x-]`rhscl/python-*`), Ruby ([x-]`rhscl/ruby-*`), Node.js
([x-]`rhscl/nodejs-*`) and Perl ([x-]`rhscl/perl-*`) rhscl images.

Keep in mind that while UBI images are freely available and redistributable,
Red Hat support for these images is only available through Red Hat
product subscriptions.

See
link:https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html-single/building_running_and_managing_containers/index#using_red_hat_universal_base_images_standard_minimal_and_runtimes[Using Red Hat Universal Base Images]
in the Red Hat Enterprise Linux documentation for information on how to use and build on
standard, minimal and init UBI images.