Receive: allow unlimited head_series_limit tenants

With this commit we now allow to configure tenants with unlimited active
series limit by setting the limit to `0`. Prior to this commit setting a
per tenant limit to `0` would cause the tenant to be unable to write any
metrics at all.

This fixes: #6393

Signed-off-by: Jacob Baungard Hansen <jacobbaungard@redhat.com>

docs/components/receive.md

@@ -241,7 +241,7 @@ Under `global`:
 - `meta_monitoring_http_client`: Optional YAML field specifying HTTP client config for meta-monitoring.
 
 Under `default` and per `tenant`:
-- `head_series_limit`: Specifies the total number of active (head) series for any tenant, across all replicas (including data replication), allowed by Thanos Receive.
+- `head_series_limit`: Specifies the total number of active (head) series for any tenant, across all replicas (including data replication), allowed by Thanos Receive. Set to 0 for unlimited.
 
 NOTE:
 - It is possible that Receive ingests more active series than the specified limit, as it relies on meta-monitoring, which may not have the latest data for current number of active series of a tenant at all times.

pkg/receive/head_series_limiter.go

@@ -155,6 +155,11 @@ func (h *headSeriesLimit) isUnderLimit(tenant string) (bool, error) {
 		limit = h.defaultLimit
 	}
 
+	// If tenant limit is 0 we treat it as unlimited.
+	if limit == 0 {
+		return true, nil
+	}
+
 	if v >= float64(limit) {
 		level.Error(h.logger).Log("msg", "tenant above limit", "tenant", tenant, "currentSeries", v, "limit", limit)
 		h.limitedRequests.WithLabelValues(tenant).Inc()

test/e2e/e2ethanos/services.go

@@ -500,6 +500,7 @@ type ReceiveBuilder struct {
 	maxExemplars        int
 	ingestion           bool
 	limit               int
+	tenantsLimits       receive.TenantsWriteLimitsConfig
 	metaMonitoring      string
 	metaMonitoringQuery string
 	hashringConfigs     []receive.HashringConfig
@@ -554,9 +555,10 @@ func (r *ReceiveBuilder) WithRelabelConfigs(relabelConfigs []*relabel.Config) *R
 	return r
 }
 
-func (r *ReceiveBuilder) WithValidationEnabled(limit int, metaMonitoring string, query ...string) *ReceiveBuilder {
+func (r *ReceiveBuilder) WithValidationEnabled(limit int, metaMonitoring string, tenantsLimits receive.TenantsWriteLimitsConfig, query ...string) *ReceiveBuilder {
 	r.limit = limit
 	r.metaMonitoring = metaMonitoring
+	r.tenantsLimits = tenantsLimits
 	if len(query) > 0 {
 		r.metaMonitoringQuery = query[0]
 	}
@@ -611,6 +613,10 @@ func (r *ReceiveBuilder) Init() *e2emon.InstrumentedRunnable {
 			},
 		}
 
+		if r.tenantsLimits != nil {
+			cfg.WriteLimits.TenantsLimits = r.tenantsLimits
+		}
+
 		b, err := yaml.Marshal(cfg)
 		if err != nil {
 			return &e2emon.InstrumentedRunnable{Runnable: e2e.NewFailedRunnable(r.Name(), errors.Wrapf(err, "generate limiting file: %v", hashring))}

test/e2e/receive_test.go

@@ -813,9 +813,13 @@ test_metric{a="2", b="2"} 1`)
 			},
 		}
 
-		i1Runnable := ingestor1.WithRouting(1, h).WithValidationEnabled(10, "http://"+meta.GetMonitoringRunnable().InternalEndpoint(e2edb.AccessPortName)).Init()
-		i2Runnable := ingestor2.WithRouting(1, h).WithValidationEnabled(10, "http://"+meta.GetMonitoringRunnable().InternalEndpoint(e2edb.AccessPortName)).Init()
-		i3Runnable := ingestor3.WithRouting(1, h).WithValidationEnabled(10, "http://"+meta.GetMonitoringRunnable().InternalEndpoint(e2edb.AccessPortName)).Init()
+		tenantsLimits := receive.TenantsWriteLimitsConfig{
+			"unlimited-tenant": receive.NewEmptyWriteLimitConfig().SetHeadSeriesLimit(0),
+		}
+
+		i1Runnable := ingestor1.WithRouting(1, h).WithValidationEnabled(10, "http://"+meta.GetMonitoringRunnable().InternalEndpoint(e2edb.AccessPortName), tenantsLimits).Init()
+		i2Runnable := ingestor2.WithRouting(1, h).WithValidationEnabled(10, "http://"+meta.GetMonitoringRunnable().InternalEndpoint(e2edb.AccessPortName), tenantsLimits).Init()
+		i3Runnable := ingestor3.WithRouting(1, h).WithValidationEnabled(10, "http://"+meta.GetMonitoringRunnable().InternalEndpoint(e2edb.AccessPortName), tenantsLimits).Init()
 
 		testutil.Ok(t, e2e.StartAndWaitReady(i1Runnable, i2Runnable, i3Runnable))
 
@@ -824,7 +828,7 @@ test_metric{a="2", b="2"} 1`)
 
 		testutil.Ok(t, querier.WaitSumMetricsWithOptions(e2emon.Equals(3), []string{"thanos_store_nodes_grpc_connections"}, e2emon.WaitMissingMetrics()))
 
-		// We run two avalanches, one tenant which exceeds the limit, and one tenant which remains under it.
+		// We run three avalanches, one tenant which exceeds the limit, one tenant which remains under it, and one for the unlimited tenant.
 
 		// Avalanche in this configuration, would send 5 requests each with 10 new timeseries.
 		// One request always fails due to TSDB not being ready for new tenant.
@@ -864,7 +868,26 @@ test_metric{a="2", b="2"} 1`)
 				TenantID: "under-tenant",
 			})
 
-		testutil.Ok(t, e2e.StartAndWaitReady(avalanche1, avalanche2))
+		// Avalanche in this configuration, would send 5 requests each with 10 new timeseries.
+		// One request always fails due to TSDB not being ready for new tenant.
+		// So without limiting we end up with 40 timeseries and 40 samples.
+		avalanche3 := e2ethanos.NewAvalanche(e, "avalanche-3",
+			e2ethanos.AvalancheOptions{
+				MetricCount:    "10",
+				SeriesCount:    "1",
+				MetricInterval: "30",
+				SeriesInterval: "3600",
+				ValueInterval:  "3600",
+
+				RemoteURL:           e2ethanos.RemoteWriteEndpoint(ingestor1.InternalEndpoint("remote-write")),
+				RemoteWriteInterval: "30s",
+				RemoteBatchSize:     "10",
+				RemoteRequestCount:  "5",
+
+				TenantID: "unlimited-tenant",
+			})
+
+		testutil.Ok(t, e2e.StartAndWaitReady(avalanche1, avalanche2, avalanche3))
 
 		// Here, 3/5 requests are failed due to limiting, as one request fails due to TSDB readiness and we ingest one initial request.
 		// 3 limited requests belong to the exceed-tenant.
@@ -876,7 +899,7 @@ test_metric{a="2", b="2"} 1`)
 		ingestor1Name := e.Name() + "-" + ingestor1.Name()
 		// Here for exceed-tenant we go above limit by 10, which results in 0 value.
 		queryWaitAndAssert(t, ctx, meta.GetMonitoringRunnable().Endpoint(e2edb.AccessPortName), func() string {
-			return fmt.Sprintf("sum(prometheus_tsdb_head_series{tenant=\"exceed-tenant\"}) - on() thanos_receive_head_series_limit{instance=\"%s:8080\", job=\"receive-i1\"}", ingestor1Name)
+			return fmt.Sprintf("sum(prometheus_tsdb_head_series{tenant=\"exceed-tenant\"}) - on() thanos_receive_head_series_limit{instance=\"%s:8080\", job=\"receive-i1\", tenant=\"\"}", ingestor1Name)
 		}, time.Now, promclient.QueryOptions{
 			Deduplicate: true,
 		}, model.Vector{
@@ -888,7 +911,7 @@ test_metric{a="2", b="2"} 1`)
 
 		// For under-tenant we stay at -5, as we have only pushed 5 series.
 		queryWaitAndAssert(t, ctx, meta.GetMonitoringRunnable().Endpoint(e2edb.AccessPortName), func() string {
-			return fmt.Sprintf("sum(prometheus_tsdb_head_series{tenant=\"under-tenant\"}) - on() thanos_receive_head_series_limit{instance=\"%s:8080\", job=\"receive-i1\"}", ingestor1Name)
+			return fmt.Sprintf("sum(prometheus_tsdb_head_series{tenant=\"under-tenant\"}) - on() thanos_receive_head_series_limit{instance=\"%s:8080\", job=\"receive-i1\", tenant=\"\"}", ingestor1Name)
 		}, time.Now, promclient.QueryOptions{
 			Deduplicate: true,
 		}, model.Vector{
@@ -918,6 +941,16 @@ test_metric{a="2", b="2"} 1`)
 			},
 		})
 
+		// Query meta-monitoring solution to assert that 40 timeseries have been ingested for unlimited-tenant.
+		queryWaitAndAssert(t, ctx, meta.GetMonitoringRunnable().Endpoint(e2edb.AccessPortName), func() string { return "sum(prometheus_tsdb_head_series{tenant=\"unlimited-tenant\"})" }, time.Now, promclient.QueryOptions{
+			Deduplicate: true,
+		}, model.Vector{
+			&model.Sample{
+				Metric: model.Metric{},
+				Value:  model.SampleValue(40),
+			},
+		})
+
 		// Query meta-monitoring solution to assert that 3 requests were limited for exceed-tenant and none for under-tenant.
 		queryWaitAndAssert(t, ctx, meta.GetMonitoringRunnable().Endpoint(e2edb.AccessPortName), func() string { return "thanos_receive_head_series_limited_requests_total" }, time.Now, promclient.QueryOptions{
 			Deduplicate: true,