The half that makes the rest work: a degraded backup target recorded only in
config is the silent-degradation pattern this arc has spent a week removing.
Part 3 -- POST /api/backup-target/assign moves the target via the agent's
POST /backup/target. It is the ONLY writer of the role: registration does not set
it, the drive-gate does not, no scheduler does. Declining is not calling it. The
agent returns restart_required rather than restarting itself, because restarting
with a backup in flight records a spurious tier failure for a backup that
actually succeeded (E-1 did exactly that).
Part 4 -- GET /api/backup-target returns the state and, when degraded, Hungarian
copy in FACT -> CONSEQUENCE -> REMEDY order, pinned by a test: a customer told
only the fact cannot act on it.
Healthy renders NOTHING -- no badge, no reassurance, no tonal change.
degradedMessageFor is the single decision point, so exactly one place could start
decorating a working box. Red-proofed: reassuring on the healthy branch fails
Scenario E.
UNKNOWN is not degraded: an unreachable or pre-R-82 agent means we could not ask,
which is not evidence of degradation (R-88 Part 2's class).
A HOLLOW TEST caught by its own red-proof: TestUnknownStateRendersNothing used
{Known:false} with Degraded left false, so it passed even with the !Known guard
deleted -- the second condition covered for it. Now {Known:false, Degraded:true},
which fails properly. Without the red-proof the test would have been decoration.
State is derived from the AGENT, never from our intent flag: on the two boxes
migrated by hand in E-1 the intent was never recorded while the drive really is
the target.
MinAgent: 0.113.0
Green gate: build + vet + test rc=0 (27 packages), run separately from this commit.
MinAgent UNCHANGED — degrades gracefully against ANY older agent.
The agent gained per-target tiers in v0.97.0. The controller owns quiescing,
so the multi-tier schedule is reconciled here: every due tier is collected up
front and run inside ONE quiesce window (one stop, N sequential backups, one
resume). Two cycles on the weekly night would mean two app outages for one
night's work.
Dedup rule: local-only -> one quiesce; PBS-only -> one quiesce; BOTH due ->
ONE window with both backups inside; neither -> no quiesce.
- quiesce.TieredBackend + BackupTier + ErrTiersUnsupported (optional extension)
- agentapi: BackupTiers/BackupDueFor/StartBackupFor/BackupStatusFor;
targetQuery("") yields an EMPTY suffix so untargeted hits the pre-R-82 route
byte-for-byte
- Loop.resolveDueTiers = the dedup rule in one place, agent order preserved
- quiesceAndPollTiers + pollTier: app stays quiesced until the LAST tier
snapshots (resuming earlier loses app-consistency on the DR tier). Consequence
stated in the docs: both-due-night downtime = first tier's full backup + last
tier's snapshot, which is why tiers run fast-first.
- Manual 'Mentes most' covers EVERY tier, due-ness ignored.
- Window-gate safety valve now uses the OLDEST due tier, so a stale DR tier
cannot be starved by a fresher local one.
Capability detection: /backup/tiers 404 = pre-R-82 agent (the documented
route-probe mechanism). Not a featureProbes row on purpose — the loop needs the
tier LIST, not a yes/no. Degrade logged exactly once per process.
Tests +11, full suite green. Red-proofs #2 and #3 observed and restored.