DNF.MODULARITY(7) DNF DNF.MODULARITY(7)
NAME
dnf.modularity - Modularity in DNF
Modularity is new way of building, organizing and delivering packages.
For more details see: https://docs.pagure.org/modularity/
DEFINITIONS
modulemd
Every repository can contain modules metadata with modulemd doc-
uments. These documents hold metadata about modules such as
Name, Stream or list of packages.
(non-modular) package
Package that doesn't belong to a module.
modular package
Package that belongs to a module. It is listed in modulemd under
the artifacts section. Modular packages can be also identified
by having %{modularitylabel} RPM header set.
(module) stream
Stream is a collection of packages, a virtual repository. It is
identified with Name and Stream from modulemd separated with
colon, for example "postgresql:9.6".
Module streams can be active or inactive. active means the RPM
packages from this stream are included in the set of available
packages. Packages from inactive streams are filtered out.
Streams are active either if marked as default or if they are
explicitly enabled by a user action. Streams that satisfy depen-
dencies of default or enabled streams are also considered
active. Only one stream of a particular module can be active at
a given point in time.
PACKAGE FILTERING
Without modules, packages with the highest version are used by default.
Module streams can distribute packages with lower versions than avail-
able in the repositories available to the operating system. To make
such packages available for installs and upgrades, the non-modular
packages are filtered out when their name or provide matches against a
modular package name from any enabled, default, or dependent stream.
Modular source packages will not cause non-modular binary packages to
be filtered out.
HOTFIX REPOSITORIES
In special cases, a user wants to cherry-pick individual packages pro-
vided outside module streams and make them available on along with
packages from the active streams. Under normal circumstances, such
packages are filtered out or rejected from getting on the system by
Fail-safe mechanisms. To make the system use packages from a reposi-
tory regardless of their modularity, specify module_hotfixes=true in
the .repo file. This protects the repository from package filtering.
Please note the hotfix packages do not override module packages, they
only become part of available package set. It's the package Epoch, Ver-
sion and Release what determines if the package is the latest.
FAIL-SAFE MECHANISMS
Repositories with module metadata are unavailable
When a repository with module metadata is unavailable, package filter-
ing must keep working. Non-modular RPMs must remain unavailable and
must never get on the system.
This happens when:
o user disables a repository via --disablerepo or uses --repoid
o user removes a .repo file from disk
o repository is not available and has skip_if_unavailable=true
DNF keeps copies of the latest modulemd for every active stream and
uses them if there's no modulemd available for the stream. This keeps
package filtering working correctly.
The copies are made any time a transaction is resolved and started.
That includes RPM transactions as well as any dnf module <enable|dis-
able|reset> operations.
When the fail-safe data is used, dnf show such modules as part of @mod-
ulefailsafe repository.
Orphaned modular packages
All packages that are built as a part of a module have %{modularityla-
bel} RPM header set. If such package becomes part of RPM transaction
and cannot be associated with any available modulemd, DNF prevents from
getting it on the system (package is available, but cannot be
installed, upgraded, etc.). Packages from Hotfix repositories or Com-
mandline repository are not affected by Fail-safe mechanisms.
AUTHOR
See AUTHORS in DNF source distribution.
COPYRIGHT
2012-2020, Red Hat, Licensed under GPLv2+
4.7.0 Apr 08, 2024 DNF.MODULARITY(7)