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Revision as of 16:45, 28 December 2021 by Chrismurphy (talk | contribs)

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


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

Documentation

Release Notes