Run per-validator OpenStack work in parallel so all validators start at once

The orchestrator claimed idle validators one by one and associated each
floating IP synchronously (~30 s per address), so 20 validators started
about 30 s apart. Aggregation/disassociation and lease reclaim were
sequential in the same way.

The slow OpenStack calls now run in one goroutine per address, guarded by
an in-flight set against duplicates. control-api runs Tick in Async mode
(Tick does not wait); tests keep the waiting mode.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

bin/SHA256SUMS

@@ -1,4 +1,4 @@
-26ff297b66a0c974b7143179e44a58f476265482cd1929bc01a95ad29e50ca7a  control-api
+4562d3cf3db8075b5a1213b582359991e3f58c819151cf7b25276cba0a4e5985  control-api
 091ad94b5706b1778b181542de7a4b251cd16c421144269d0955769603d51e06  validator-agent
 3e9e14dbb361ee76aaad7c1da6864b3ea111e0ed151403f904b12485631bbf75  prober
 d72234688eb1954dbff420ca1c8e83b83ceab561b18a0336af0f73fe4d9ac8be  admin-dashboard

cmd/control-api/main.go

@@ -59,6 +59,7 @@ func run(configPath string, log *slog.Logger) error {
 	}
 
 	orch := orchestrator.New(database, osClient, cfg, log)
+	orch.Async = true // slow OpenStack calls run per address, Tick never waits for them
 	// Background jobs (the floating-IP scan) live as long as the process, not
 	// as long as the HTTP request or loop iteration that started them.
 	orch.SetContext(ctx)

internal/orchestrator/orchestrator.go

@@ -49,6 +49,36 @@ type Orchestrator struct {
 	// scan is the background floating-IP scan job (see scanjob.go); its zero
 	// value is ready to use.
 	scan scanJob
+
+	// Async makes Tick return without waiting for the slow per-address work
+	// (OpenStack calls): each address is handled in its own goroutine, so one
+	// slow cloud call never delays another validator. With Async=false (the
+	// default, used by tests) Tick runs the same work in parallel but waits
+	// for all of it before returning.
+	Async bool
+
+	// inflight holds the keys of work already running in a goroutine, so the
+	// next Tick does not start the same work twice.
+	inflight sync.Map
+	wg       sync.WaitGroup
+}
+
+// Wait blocks until all background work started by Tick has finished.
+func (o *Orchestrator) Wait() { o.wg.Wait() }
+
+// spawn runs fn in its own goroutine unless work with the same key is
+// already running. It returns immediately; callers that need the result
+// wait with o.wg (see runAll).
+func (o *Orchestrator) spawn(key string, fn func()) {
+	if _, busy := o.inflight.LoadOrStore(key, struct{}{}); busy {
+		return
+	}
+	o.wg.Add(1)
+	go func() {
+		defer o.wg.Done()
+		defer o.inflight.Delete(key)
+		fn()
+	}()
 }
 
 // New constructs an Orchestrator. Egress check types/targets, prober sites,
@@ -79,6 +109,10 @@ func (o *Orchestrator) leaseTTL() time.Duration {
 // validators, sweep the checking window for ready-to-aggregate IPs, and
 // reclaim expired leases. Intended to be called on a fixed interval
 // (Cfg.PollIntervalSeconds) by the caller (cmd/control-api/main.go).
+//
+// The slow part of every step (calls to OpenStack) runs per address in its
+// own goroutine, so validators never wait for each other. In Async mode
+// Tick does not wait for those goroutines; otherwise it waits for them.
 func (o *Orchestrator) Tick(ctx context.Context) {
 	if err := o.assignIdleValidators(ctx); err != nil {
 		o.Log.Error("assign idle validators", "err", err)
@@ -89,6 +123,9 @@ func (o *Orchestrator) Tick(ctx context.Context) {
 	if err := o.sweepExpiredLeases(ctx); err != nil {
 		o.Log.Error("sweep expired leases", "err", err)
 	}
+	if !o.Async {
+		o.wg.Wait()
+	}
 }
 
 // assignIdleValidators claims the next queued IP for every currently idle
@@ -108,9 +145,12 @@ func (o *Orchestrator) assignIdleValidators(ctx context.Context) error {
 			continue // no work available for this validator right now
 		}
 		o.Log.Info("claimed ip", "validator", v.ValidatorID, "ip", item.IPAddress, "ip_id", item.ID)
-		if err := o.associateFIP(ctx, v.ValidatorID, v.OSPortID, item); err != nil {
-			o.Log.Error("associate fip", "validator", v.ValidatorID, "ip", item.IPAddress, "err", err)
-		}
+		v, item := v, item
+		o.spawn("assign:"+v.ValidatorID, func() {
+			if err := o.associateFIP(ctx, v.ValidatorID, v.OSPortID, item); err != nil {
+				o.Log.Error("associate fip", "validator", v.ValidatorID, "ip", item.IPAddress, "err", err)
+			}
+		})
 	}
 	return nil
 }
@@ -453,9 +493,12 @@ func (o *Orchestrator) sweepCheckingWindow(ctx context.Context) error {
 		if !ready {
 			continue
 		}
-		if err := o.aggregateAndRelease(ctx, item); err != nil {
-			o.Log.Error("aggregate and release", "ip_id", item.ID, "err", err)
-		}
+		item := item
+		o.spawn(fmt.Sprintf("aggregate:%d", item.ID), func() {
+			if err := o.aggregateAndRelease(ctx, item); err != nil {
+				o.Log.Error("aggregate and release", "ip_id", item.ID, "err", err)
+			}
+		})
 	}
 	return nil
 }
@@ -606,14 +649,17 @@ func (o *Orchestrator) sweepExpiredLeases(ctx context.Context) error {
 		if item.OwnerValidatorID != nil {
 			validatorID = *item.OwnerValidatorID
 		}
-		o.Log.Info("lease expired, reclaiming", "ip_id", item.ID, "ip", item.IPAddress, "validator", validatorID)
-		if item.FIPID != "" {
-			if err := o.OS.DisassociateFloatingIP(ctx, item.FIPID); err != nil {
-				o.Log.Error("disassociate fip on lease reclaim", "ip_id", item.ID, "err", err)
+		item, validatorID := item, validatorID
+		o.spawn(fmt.Sprintf("lease:%d", item.ID), func() {
+			o.Log.Info("lease expired, reclaiming", "ip_id", item.ID, "ip", item.IPAddress, "validator", validatorID)
+			if item.FIPID != "" {
+				if err := o.OS.DisassociateFloatingIP(ctx, item.FIPID); err != nil {
+					o.Log.Error("disassociate fip on lease reclaim", "ip_id", item.ID, "err", err)
+				}
 			}
-		}
-		o.event(ctx, "control-api", "", &item.ID, "lease_expired", fmt.Sprintf(`{"validator_id":%q}`, validatorID))
-		o.requeueOrFail(ctx, item.ID, validatorID, "lease expired")
+			o.event(ctx, "control-api", "", &item.ID, "lease_expired", fmt.Sprintf(`{"validator_id":%q}`, validatorID))
+			o.requeueOrFail(ctx, item.ID, validatorID, "lease expired")
+		})
 	}
 	return nil
 }

internal/orchestrator/orchestrator_test.go

@@ -3,6 +3,7 @@ package orchestrator
 import (
 	"context"
 	"errors"
+	"fmt"
 	"log/slog"
 	"os"
 	"path/filepath"
@@ -942,3 +943,56 @@ func TestScanFloatingIPsNoFreeAddressesIsNotAnError(t *testing.T) {
 		t.Fatalf("expected nothing added, got %+v", result)
 	}
 }
+
+// slowOS adds a fixed delay to every OpenStack call, like a loaded cloud.
+type slowOS struct {
+	*openstack.MockClient
+	delay time.Duration
+}
+
+func (s slowOS) GetFloatingIPByAddress(ctx context.Context, a string) (*openstack.FloatingIP, error) {
+	time.Sleep(s.delay)
+	return s.MockClient.GetFloatingIPByAddress(ctx, a)
+}
+
+func (s slowOS) AssociateFloatingIP(ctx context.Context, fipID, portID string) error {
+	time.Sleep(s.delay)
+	return s.MockClient.AssociateFloatingIP(ctx, fipID, portID)
+}
+
+// All idle validators must start in the same tick: one slow cloud call may
+// not delay the others (20 validators x 2 calls x 200ms = 8s if sequential).
+func TestValidatorsStartInParallel(t *testing.T) {
+	ctx := context.Background()
+	o, d, mock := newTestOrchestrator(t, 180)
+	o.OS = slowOS{MockClient: mock, delay: 200 * time.Millisecond}
+
+	const n = 20
+	var addrs []string
+	for i := 1; i <= n; i++ {
+		addr := fmt.Sprintf("10.0.0.%d", i)
+		addrs = append(addrs, addr)
+		mock.Seed(fmt.Sprintf("fip-%d", i), addr, "svc-project")
+		if err := d.RegisterValidator(ctx, fmt.Sprintf("validator-%d", i), "h", fmt.Sprintf("port-%d", i), "v"); err != nil {
+			t.Fatalf("register validator: %v", err)
+		}
+	}
+	if err := d.SeedQueue(ctx, addrs); err != nil {
+		t.Fatalf("seed queue: %v", err)
+	}
+
+	start := time.Now()
+	o.Tick(ctx)
+	if elapsed := time.Since(start); elapsed > 2*time.Second {
+		t.Fatalf("tick took %s: validators are served one after another", elapsed)
+	}
+	for _, a := range addrs {
+		ip, err := d.GetIPByAddress(ctx, a)
+		if err != nil {
+			t.Fatalf("get ip %s: %v", a, err)
+		}
+		if ip.State != db.IPAwaitingSelfCheck {
+			t.Fatalf("ip %s: expected awaiting_self_check, got %s", a, ip.State)
+		}
+	}
+}