Proposal for turning the single containers root into a registry of
locations, with each app choosing one — so bulk data can live on a
second disk or an external drive while the control plane stays put.
Records what the codebase already gives us for free (relative compose
volumes, self-describing app dirs, the backup-locations pattern), the
~200 call sites that must move behind an appDir() resolver, and the
one constraint that shapes everything: the root helpers bake their
paths at install precisely so the manager cannot redirect a root
chown, so the location registry has to be root-owned with an
empty-directory admission rule.
Also notes a latent bug found while checking: restore builds its
include path from the LOCAL containers root, so migrating between
hosts with different --containers-dir values silently restores nothing.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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