3.1.1.2 About Application Streams

Oracle Linux 8 introduces the concept of Application Streams, where multiple versions of user-space components can be delivered and updated more frequently than the core operating system packages. Application Streams contain all of the necessary system components and a range of applications that were previously distributed in Software Collections, as well as other products and programs.

The content in the AppStream repository is available in two formats: RPM and modules, which are an extension of the RPM format. Traditional RPM packages are available for immediate installation. Traditional package management methods and installation are transparently supported for all content. Modules are similar to Software Collections, in that they provide a mechanism by which multiple, major versions of a component are made available for installation in the AppStream repository. Note that modules are easier than Software Collections to install and use. The appropriate combination of modules and streams is automatically used to enable the installation of packages that rely on modular features.

The AppStream repository contains the following components:

  • Modules: Are a set of RPM packages that are grouped and installed together. Modules can contain several streams that consist of multiple versions of applications that can be installed. A module stream is enabled to provide system access to the RPM packages that are contained within that module stream.

    A typical module can contain the following different types of packages: packages with an application, packages with the application’s specific dependency libraries, packages with documentation for the application, and packages with helper utilities

  • Module streams: Contain a different version of packages and their dependencies. Modules can have multiple streams and each stream receives updates independently. Although modules can have multiple streams, only one of its streams can be enabled and provide its packages to enable the installation of the respective version of content. Typically, the stream with the latest version is selected as the default stream and will be used when operations do not specify a particular stream or a different stream is not enabled.

    Note

    Oracle recommends that you use the latest stream for any module that is installed, even though other streams may continue to receive limited support.

  • Module profiles: List certain packages that are to be installed at the same time for a particular use case. Each module can have one or more profiles.

For more detailed information about modules, including examples, see the chapter on DNF in the Oracle Linux Software Management Guide for Release 8.