OS updates, guest fast lane (11 §8 step 2): felhom-os-apply wrapper (R1-R13 refusals, repair first, snapshot.debian.org fallback), FELHOM_OSAPPLY sudoers, the OS leg after the primary backup, hub os_update block + os-report, --selftest=os-update

No automatic undo: a customer guest cannot be snapshotted (R-837, measured).

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

cmd/felhom-agent/main.go

@@ -48,6 +48,7 @@ import (
 	"gitea.dooplex.hu/admin/felhom-agent/internal/pbsdr"
 	"gitea.dooplex.hu/admin/felhom-agent/internal/poke"
 	"gitea.dooplex.hu/admin/felhom-agent/internal/provision"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/osupdate"
 	"gitea.dooplex.hu/admin/felhom-agent/internal/proxmox"
 	"gitea.dooplex.hu/admin/felhom-agent/internal/reconcile"
 	"gitea.dooplex.hu/admin/felhom-agent/internal/restorespace"
@@ -242,6 +243,8 @@ func main() {
 		os.Exit(runSelftestRestoreTest(context.Background(), cfg, logger, archive))
 	case "restore-test-due":
 		os.Exit(runSelftestRestoreTestDue(context.Background(), cfg, logger))
+	case "os-update":
+		os.Exit(runSelftestOSUpdate(context.Background(), cfg, logger, vmid))
 	case "pbs-verify":
 		os.Exit(runSelftestPBSVerify(context.Background(), cfg, logger))
 	case "lanresolver":
@@ -839,6 +842,10 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 	// The "Down" channel sync hook: on each heartbeat, fetch desired-state when the generation
 	// advances. The loop calls it via the EnvelopeObserver seam (hub does not import desired).
 	desiredSyncer := desired.NewSyncer(client, desiredProvider, logger)
+	// OS updates, guest fast lane (agent v0.140.0, `11-os-updates.md` §8 step 2): the leg consumes the hub's
+	// os_update block and runs after each successful primary whole-guest backup (wired on the local API below).
+	osLeg := newOSLeg(cfg, client, logger)
+	desiredSyncer.AddConsumer(osLeg)
 	// S5: consume a host_loss restore_directive into an inspectable restore PLAN (derive + surface,
 	// execute nothing). The recipe is fetched on-demand (rare directive) via a fresh Collect.
 	desiredSyncer.AddConsumer(dr.NewConsumer(func(ctx context.Context) *hub.DRRecipeHostHalf {
@@ -1112,6 +1119,17 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 		},
 	}
 	localSrv := buildLocalAPIServer(cfg, px, backupStore, heavyOps, observer, driveKnown, hostOps, gate, collector, client, intentRec, guestBindStore, formatJobStore, logRing, escrowCeremonyCfg, logger, &localTokens)
+	if localSrv != nil {
+		localSrv.SetAfterPrimaryBackup(func(ctx context.Context, vmid int) {
+			// Let the controller finish bringing its apps back after the backup, then run (still under the gate).
+			select {
+			case <-ctx.Done():
+				return
+			case <-time.After(90 * time.Second):
+			}
+			osLeg.Run(ctx, vmid, "night")
+		})
+	}
 	if localTokens != nil {
 		defer localTokens.Close()
 	}
@@ -3483,3 +3501,57 @@ func (f *selftestFlag) Set(v string) error {
 	}
 	return nil
 }
+
+// newOSLeg builds the OS-update leg (agent v0.140.0). The wrapper runs through sudo (FELHOM_OSAPPLY); the plan and
+// the once-per-night marker live in the agent's own os/ dir.
+func newOSLeg(cfg config.Config, client *hub.Client, logger *slog.Logger) *osupdate.Leg {
+	mode := proxmox.RunnerMode(cfg.Privileged.Mode)
+	if mode == "" {
+		mode = proxmox.RunnerSudo
+	}
+	l := &osupdate.Leg{
+		Runner:    &proxmox.ExecRunner{Mode: mode, SudoPath: cfg.Privileged.SudoPath},
+		Logger:    logger,
+		PlanDir:   osupdate.DefaultPlanDir,
+		StatePath: filepath.Join(osupdate.DefaultPlanDir, "last-night-run"),
+	}
+	if client != nil {
+		l.Hub = client
+	}
+	return l
+}
+
+// runSelftestOSUpdate is the OS leg's DEBUG ACTION (agent v0.140.0): one pass for -vmid, now, exactly as the night
+// runs it after a backup — the hub's os_update block (fetched fresh), the wrapper via sudo, the health wait, the
+// report to the hub — with trigger "debug" (never throttled, and it does NOT count as a night run for approval).
+// Run it as the agent user:  sudo -u felhom-agent felhom-agent --config … --selftest=os-update -vmid 9201
+func runSelftestOSUpdate(ctx context.Context, cfg config.Config, logger *slog.Logger, vmid int) int {
+	if vmid <= 0 {
+		fmt.Fprintln(os.Stderr, "selftest=os-update: -vmid is required")
+		return 2
+	}
+	client, err := hub.NewClient(cfg.Hub, logger)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "selftest=os-update: hub client:", err)
+		return 1
+	}
+	leg := newOSLeg(cfg, client, logger)
+	resp, err := client.FetchDesiredState(ctx)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "selftest=os-update: desired state:", err)
+		return 1
+	}
+	leg.SetBlock(resp.DesiredState.OSUpdate)
+	b := leg.Block()
+	fmt.Printf("=== felhom-agent %s selftest=os-update vmid=%d ring=%d enabled=%v release=%v ===\n", version, vmid, b.Ring, b.Enabled, b.Release != nil)
+	rep := leg.Run(ctx, vmid, "debug")
+	printJSON("os-update report", map[string]any{"run_id": rep.RunID, "ring": rep.Ring, "release_id": rep.ReleaseID,
+		"mode": rep.Mode, "outcome": rep.Outcome, "healthy": rep.Healthy, "health_reason": rep.HealthReason,
+		"upgraded": rep.Upgraded, "pending": len(rep.Pending), "not_covered": rep.NotCovered,
+		"restart_needed": rep.RestartNeeded, "docker_restart_needed": rep.DockerRestartNeeded, "refused": rep.Refused})
+	switch rep.Outcome {
+	case "applied", "nothing", "inventory", "skipped":
+		return 0
+	}
+	return 1
+}