Chapter 1. Using AppStream

The following sections provide an overview of the concepts related to the AppStream repository in Red Hat Enterprise Linux 8.

1.1. Distribution of content in RHEL 8

RHEL 8 content is distributed through the two main repositories: BaseOS and AppStream.

BaseOS
Content in the BaseOS repository is intended to provide the core set of the underlying OS functionality that provides the foundation for all installations. This content is available in the RPM format and is subject to support terms similar to those in previous releases of Red Hat Enterprise Linux.
AppStream
Content in the AppStream repository includes additional user space applications, runtime languages, and databases in support of the varied workloads and use cases. Content in AppStream is available in one of two formats - the familiar RPM format and an extension to the RPM format called modules.
Important

Both BaseOS and AppStream content sets are required for a basic RHEL installation, and are available with all RHEL subscriptions. For installation instructions, see the Installing and Deploying RHEL document.

1.2. Application Streams

Red Hat Enterprise Linux 8 introduces the concept of Application Streams - versions of user space components. Multiple versions of these components are now delivered and updated more frequently than the core operating system packages. This provides greater flexibility to customize Red Hat Enterprise Linux without impacting the underlying stability of the platform or specific deployments.

Components made available as Application Streams can be packaged as modules or RPM packages and are delivered through the AppStream repository in Red Hat Enterprise Linux 8. Each AppStream component has a given life cycle.

Note

Not all modules are Application Streams. Dependencies of other modules are not considered AppStream components.

Each module defines its own lifecycle which is closer to the natural life of the application rather than the RHEL lifecycle. To find out what Application Streams are available and what is their length of support, see the Red Hat Enterprise Linux 8 Application Streams Life Cycle page.

1.3. Packaging methods in RHEL 8

The AppStream repository contains content packaged in two ways:

Individual RPM packages
Traditional RPM packages available for immediate installation.
Modules
Modules are collections of packages representing a logical unit: an application, a language stack, a database, or a set of tools. These packages are built, tested, and released together.

1.4. Package management using YUM in RHEL 8

The YUM package management tool is now based on the DNF technology and it adds support for the new modular features.

Usage of YUM has not been changed when handling individual RPM packages. For handling the modular content, the yum module command has been added. See Chapter 4, Installing RHEL 8 content for additional details.

Where required, the modular functionality automatically selects the appropriate combination of modules and streams to enable installation of logical sets of packages for convenient usage.