R-1192 follow-up: report host swap vs the guests' swap allowance (log once, hub alarm, local API); R-1194: no OOB stanza before the first felhom-sshd pass; unreleased

internal/hub/collect.go

@@ -11,6 +11,7 @@ import (
 	"os"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"gitea.dooplex.hu/admin/felhom-agent/internal/capability"
@@ -136,6 +137,8 @@ type Collector struct {
 	selfSHA          func() string // R-349: sha256 of the running binary; default runningBinarySHA256
 	logger           *slog.Logger
 	now              func() time.Time
+	// swapShortWarned (R-1192): the host-swap-short WARN is logged once per state change, not every report.
+	swapShortWarned atomic.Bool
 }
 
 // NewCollector builds a collector. hostID echoes config.Hub.HostID; agentVersion is
@@ -375,6 +378,8 @@ func (c *Collector) Collect(ctx context.Context) (*HostReport, error) {
 	}
 
 	host := hostMetrics(c.px.Node(), ns)
+	guests := c.collectGuests(ctx)
+	c.applySwap(&host, ns, guests)          // R-1192: host swap vs the guests' swap allowance
 	host.CPUTempC = c.cpuTempC(ctx)         // slice 9: operator freebie — temp now rides the hub report too
 	host.WrapperSHA256 = pbsWrapperSHA256() // R-50b(a): make privileged-artifact drift answerable
 	report := &HostReport{
@@ -383,7 +388,7 @@ func (c *Collector) Collect(ctx context.Context) (*HostReport, error) {
 		AgentVersion: c.agentVersion,
 		AgentSHA256:  c.agentSHA256(),
 		Host:         host,
-		Guests:       c.collectGuests(ctx),
+		Guests:       guests,
 		// storage_targets populated this slice (slice 5) via the observer; the rest stay
 		// defined-but-empty (slice 6). Non-nil so they marshal as [].
 		StorageTargets: c.collectStorage(ctx),
@@ -567,6 +572,7 @@ func (c *Collector) collectGuests(ctx context.Context) []Guest {
 				Cores:       cfg.Cores,
 				MemoryBytes: g.MaxMem,
 				DiskBytes:   g.MaxDisk,
+				SwapBytes:   cfg.Swap * (1 << 20),
 			}
 		}
 		guests = append(guests, entry)

internal/hub/hostswap.go

@@ -0,0 +1,39 @@
+package hub
+
+import (
+	"gitea.dooplex.hu/admin/felhom-agent/internal/proxmox"
+)
+
+// R-1192 follow-up (night 2026-10-21): the guest swap fix (every guest may swap as much as its RAM,
+// localapi/guestswap.go) moves a memory burst onto the HOST's swap. Measured on demo-hp the same day: our installer
+// gives an 8 GB / 256 GB machine 7.75 GB of host swap, so a 4096 MB guest's 4096 MB swap fits. A host with no swap
+// (a BYO install, or swap turned off) gets nothing from the fix. So the report carries both numbers, the agent says it
+// once in its log, and the hub raises host_swap_short. The agent never creates host swap itself: changing a host its
+// owner set up is a decision (felhom.eu register).
+
+// HostSwapShort reports whether the host's swap is below the guests' swap allowance. A host whose guests have no
+// swap allowance (0) is never short.
+func HostSwapShort(hostMB, guestMB int64) bool { return guestMB > 0 && hostMB < guestMB }
+
+// applySwap fills the host block's swap numbers from the node status and the guests' specs, and logs the short
+// state once per change.
+func (c *Collector) applySwap(h *HostMetrics, ns proxmox.NodeStatus, guests []Guest) {
+	hostMB := ns.Swap.Total / (1 << 20)
+	var guestMB int64
+	for _, g := range guests {
+		if g.Spec != nil {
+			guestMB += g.Spec.SwapBytes / (1 << 20)
+		}
+	}
+	h.HostSwapMB, h.GuestSwapMB = &hostMB, &guestMB
+	if HostSwapShort(hostMB, guestMB) {
+		if c.swapShortWarned.CompareAndSwap(false, true) {
+			c.logger.Warn("host-swap: the host's swap is below its guests' swap allowance — a memory burst can freeze the box (R-1192); the hub is told (host_swap_short)",
+				"host_swap_mb", hostMB, "guest_swap_mb", guestMB)
+		}
+		return
+	}
+	if c.swapShortWarned.CompareAndSwap(true, false) {
+		c.logger.Info("host-swap: the host's swap covers its guests' swap allowance again", "host_swap_mb", hostMB, "guest_swap_mb", guestMB)
+	}
+}

internal/hub/r1192_hostswap_test.go

@@ -0,0 +1,42 @@
+package hub
+
+import (
+	"bytes"
+	"log/slog"
+	"strings"
+	"testing"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/proxmox"
+)
+
+// R-1192 follow-up (night 2026-10-21): the host report carries the host's swap and the guests' swap allowance, and the
+// agent says ONCE in its log when the host's swap is below it (and once when it is covered again).
+// RED-PROOF: with applySwap not called the numbers are nil; with the CompareAndSwap removed the WARN repeats.
+func TestR1192_HostReportCarriesSwapAndWarnsOnce(t *testing.T) {
+	var buf bytes.Buffer
+	c := &Collector{logger: slog.New(slog.NewTextHandler(&buf, nil))}
+	guests := []Guest{{VMID: 9201, Spec: &GuestSpec{SwapBytes: 4096 << 20}}, {VMID: 9202, Spec: nil}}
+	var ns proxmox.NodeStatus // a host with no swap
+	for i := 0; i < 3; i++ {
+		h := HostMetrics{}
+		c.applySwap(&h, ns, guests)
+		if h.HostSwapMB == nil || h.GuestSwapMB == nil || *h.HostSwapMB != 0 || *h.GuestSwapMB != 4096 {
+			t.Fatalf("report numbers: host %v guest %v", h.HostSwapMB, h.GuestSwapMB)
+		}
+	}
+	if n := strings.Count(buf.String(), "host-swap: the host's swap is below"); n != 1 {
+		t.Fatalf("the short WARN must be logged once, got %d:\n%s", n, buf.String())
+	}
+	ns.Swap.Total = 7935 << 20 // the installer's 8 GB host
+	h := HostMetrics{}
+	c.applySwap(&h, ns, guests)
+	if *h.HostSwapMB != 7935 || HostSwapShort(*h.HostSwapMB, *h.GuestSwapMB) {
+		t.Fatalf("a covered host must not be short: %v / %v", *h.HostSwapMB, *h.GuestSwapMB)
+	}
+	if !strings.Contains(buf.String(), "covers its guests' swap allowance again") {
+		t.Fatalf("the recovery must be said once:\n%s", buf.String())
+	}
+	if HostSwapShort(0, 0) {
+		t.Fatal("a host whose guests have no swap allowance is never short")
+	}
+}

internal/hub/report.go

@@ -338,6 +338,11 @@ type HostMetrics struct {
 	//
 	// Empty = unreadable/absent, which the hub treats as UNKNOWN, never as drift.
 	WrapperSHA256 string `json:"wrapper_sha256,omitempty"`
+	// HostSwapMB / GuestSwapMB (R-1192 follow-up, night 2026-10-21): the host's swap (Proxmox node status — the
+	// kernel's SwapTotal) and the sum of its guests' swap allowance. The guest swap fix (swap = RAM) needs swap ON THE
+	// HOST behind it; the hub raises host_swap_short when the first is below the second. nil = not read (older agent).
+	HostSwapMB  *int64 `json:"host_swap_mb,omitempty"`
+	GuestSwapMB *int64 `json:"guest_swap_mb,omitempty"`
 }
 
 // Guest is one LXC. The agent reports vmid; the hub derives the guest PK
@@ -355,6 +360,7 @@ type GuestSpec struct {
 	Cores       int   `json:"cores"`
 	MemoryBytes int64 `json:"memory_bytes"`
 	DiskBytes   int64 `json:"disk_bytes"`
+	SwapBytes   int64 `json:"swap_bytes,omitempty"` // R-1192: the guest's swap allowance (PVE config `swap`, MB → bytes)
 }
 
 // Cloudflared is the box's tunnel (R-841, agent v0.141.0): the cloudflared container in the customer guest.