# Fleet Configuration Backup and Restore Boundary

**Issue:** #758 · **Card:** FCM-M4-001

This page defines evidence that must exist before a roster v1-to-v2 cutover. FCM-M4-001 lists these
prerequisites in non-executable recovery evidence but does not validate that backups exist and performs
no backup, migration, canary, or restore. FCM-M4-002 owns the executable reversible canary and rollback
gates.

## Preserve before cutover

- The authoritative v1 roster, byte-for-byte, with a SHA-256 identity.
- Existing per-agent legacy `.env`, strict `.env.local`, and quarantine files under private
  permissions.
- Reviewed per-local-agent systemd and exact-socket tmux observations.
- The canonical v2 candidate and its SHA-256 identity.
- Inventory-only remote agents and connector configuration as evidence, not local control-plane input.

`.env.generated` is a rebuildable projection and is not restored as authority. It must be regenerated
from the selected authoritative roster. `.env.local` is operator-owned strict data and must not be
overwritten or absorbed into generated output. Quarantined source remains private evidence; public
diagnostics expose only rule code, key name, and SHA-256.

## Restore requirements

A later rollback implementation must restore the authoritative roster and operator-owned environment
files, regenerate managed projections, and preserve each reviewed pre-cutover stopped/running state.
It must never start an agent observed stopped and must never reconcile an inventory-only remote or
connector entry.

The preview evidence deliberately records:

- `executable: false`;
- required backup artifacts;
- source and candidate identities;
- lifecycle observations and resulting desired states;
- environment relocation/quarantine dispositions;
- FCM-M4-002 as the executable rollback gate owner.

Do not interpret a ready preview as a completed backup, migration, canary, or rollback.
