Page Comparison

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• DNF must be used to install modular RPMs; yum does not support modularity

• Each modular RPM is built with a special ModularityLabel tag.

• DNF will not install an RPM with a ModularityTag unless it can be associated with modulemd metadata from an available repository.

AppStream Lifecycle

• Each RHEL AppStream (module stream) has its own lifecycle, which is usually not the full 10-year lifecycle of the Base OS: https://access.redhat.com/support/policy/updates/rhel8-app-streams-life-cycle.

  Image Added

• This includes most default streams.

• Some streams retire within two years (the first RHEL stream retires in April 2021).

SIMP ISO Build

Requirements

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1. SIMP 6.6.0 requires RPMs from at least one module stream from epel-modular: 389-directory-server:stable, in order to support 389ds.

Conclusions

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Requirements for SIMP ISO build + EL8 modularity

The following (derived from the In order information above) should enable us to build SIMP ISOs that distribute modular RPMs:

1. The ISO build process MUST distribute modular RPMs in “slim” subsets of their original module streams.

The alternatives are to include the entire modular repository (too big) or not ship dependencies (ISO is no longer self-sufficient)

1. In order to maintain seamless interoperability, each “slim” modular stream subset MUST use the same name + stream + version + context + architecture (N:S:V:C:A) as their upstream sources

2. If feasible, the “slimming” process SHOULD be generalized enough to apply to packages from external sources like epel-modular AND the base OS’s DVD AppStream/ repository.

Alternatives considered were to include the entire modular repository (too big) or not ship modular dependencies (ISO + download server would no be longer self-contained).

2. The old createrepo command MUST NEVER be run on a modular

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repository

This applies to both the ISO’s build process and post-installation local tooling on SIMP systems.

1. Status
   colour Purple title TODO

   The ISO’s modular repositories MUST be built with modularity-aware tools, like createrepo_c or creatrerepocreaterepo_mod from modulemd-tools. StatuscolourPurpletitleTODO

2. Local SIMP tooling MUST be changed to NEVER use createrepo to manage on modular repositories:

Implementation hints

• Places we use createrepo:

  • Status
    colour Purple title TODO

    At least two sections of the ISO’s ks auto.cfg in simp-core (EL8 only; not yet created)

  • Status
    colour Purple title TODO

    UpdateOsYumRepositoriesAction#apply() in simp config

  • Status
    colour Purple title TODO

    The update_yum_repo() method in unpack_dvd

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1. .

3. Modular repos' modulemd metadata MUST remain intact when mirrored or rebuilt.

1. The modular Modular repos MUST NOT be mirrored or rebuilt without it

2. The modulemd metadata will always be necessary in order to install these repos' modular packages—and once lost it cannot be recreated from their RPMs (unlike standard RPMs).

3. Status
   colour Purple title TODO

   Local SIMP tooling that mirrors modular repositories MUST preserve modulemd metadata (e.g., dnf reposync --download-metadata)

The “Slim” subset repos are of particular concern, since SIMP tooling is guaranteed to encounter them.