Changes/RelocateRPMToUsr

Relocate RPM database to /usr

Summary

Currently, the RPM databases is located in /var. Let's move it to /usr.

Owner

• Name: Chris Murphy
• Email: chrismurphy@fedoraproject.org
• Name: Michel Alexandre Salim
• Email: salimma@fedoraproject.org

Current status

• Targeted release: Fedora Linux 36
• Last updated: 2021-12-28
• FESCo issue: <will be assigned by the Wrangler>
• Tracker bug: <will be assigned by the Wrangler>
• Release notes tracker: <will be assigned by the Wrangler>

Detailed Description

Current location

/var/lib/rpm

New location

/usr/lib/sysimage/rpm

This will be done by creating making [code]/var/lib/rpm[/code] a symlink pointing to /usr/lib/sysimage/rpm

The proposal is to apply the new location only to new clean installs only. It will not apply to upgrades.

There will be no change to DNF as part of this change proposal. DNF's history will remain in /var until DNF 5. Discussion continues about the effect of a snapshot+rollback regime on DNF history. Relocate DNF history to /usr.

Benefit to Fedora

• The RPM and DNF databases describe the state of (primarily) /usr. Storing these databases in /usr will more easily facilitate OS rollback, without affecting /var.

• Helps align Fedora variants with each other
  • rpm-ostree based systems (including CoreOS, IoT, Silverblue, Kinoite) already use /usr/lib/sysimage for rpmdb.

• Consistency with another RPM-based distro, (open)SUSE has made this change

Scope

• Proposal owners:
  • changes in rpm and dnf-data packages
    • create the new path instead of old
    • create symlinks for the old path to new path

• Other developers:
  • changes in SElinux policy

• Release engineering: #Releng issue 10441
• Policies and guidelines: N/A (not needed for this Change)

• Trademark approval: N/A (not needed for this Change)

• Alignment with Objectives:

Upgrade/compatibility impact

Change will be applied on upgrades to Fedora 36.

How To Test

• Clean install or upgrade an existing Fedora system
• Note the changed database paths (new location) and symlinks in the old location
• Check that rpm and dnf commands work as expected, e.g.

dnf history  
rpm -qa

User Experience

Users will notice:

• symlinks in the old locations for the databases, pointing to the new locations;
• paths existing in the new locations.

Otherwise, the change should be invisible to users.

Dependencies

• rpm-ostree probably should make /usr/share/rpm a symlink to /usr/lib/sysimage/rpm, rather than the reverse as it is currently.
• PackageKit might use inotify on /var/lib/rpm need to check if it does and whether it should be changed or add the additional path

Contingency Plan

• Contingency mechanism: Revert the change, try again the next Fedora release.
• Contingency deadline: Beta freeze
• Blocks release? Yes