Changes/RelocateRPMToUsr

Relocate RPM database to /usr

Summary

Currently, the RPM databases is located in /var. Let's move it to /usr. The move is already under way in rpm-ostree-based installations, and in (open)SUSE.

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

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

/var/lib/rpm will be a symlink pointing to /usr/lib/sysimage/rpm

Feedback

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.

Upstream RPM accept the change, but institutionally don't like the loss or weakening of a very well known location for the database, and anticipate complaints.

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