prometheus.operator.*: allow setting informer_sync_timeout (#2161)

* prometheus.operator.*: allow setting informer_sync_timeout

* default to 1m

* docs

CHANGELOG.md

@@ -14,6 +14,8 @@ v1.5.1
 
 - Logs from underlying clustering library `memberlist` are now surfaced with correct level (@thampiotr)
 
+- Allow setting `informer_sync_timeout` in prometheus.operator.* components. (@captncraig)
+
 ### Bugfixes
 
 - Fixed issue with reloading configuration and prometheus metrics duplication in `prometheus.write.queue`. (@mattdurham)

docs/sources/reference/components/prometheus/prometheus.operator.podmonitors.md

@@ -34,6 +34,7 @@ Name | Type | Description | Default | Required
 ---- | ---- | ----------- | ------- | --------
 `forward_to` | `list(MetricsReceiver)` | List of receivers to send scraped metrics to. | | yes
 `namespaces` | `list(string)` | List of namespaces to search for PodMonitor resources. If not specified, all namespaces will be searched. || no
+`informer_sync_timeout` | `duration` | Timeout for initial sync of PodMonitor resources. | `1m` | no
 
 ## Blocks
 

docs/sources/reference/components/prometheus/prometheus.operator.probes.md

@@ -37,6 +37,7 @@ Name | Type | Description | Default | Required
 ---- | ---- | ----------- | ------- | --------
 `forward_to` | `list(MetricsReceiver)` | List of receivers to send scraped metrics to. | | yes
 `namespaces` | `list(string)` | List of namespaces to search for Probe resources. If not specified, all namespaces will be searched. || no
+`informer_sync_timeout` | `duration` | Timeout for initial sync of Probe resources. | `1m` | no
 
 ## Blocks
 

docs/sources/reference/components/prometheus/prometheus.operator.servicemonitors.md

@@ -36,6 +36,7 @@ Name | Type | Description | Default | Required
 ---- | ---- | ----------- | ------- | --------
 `forward_to` | `list(MetricsReceiver)` | List of receivers to send scraped metrics to. | | yes
 `namespaces` | `list(string)` | List of namespaces to search for ServiceMonitor resources. If not specified, all namespaces will be searched. || no
+`informer_sync_timeout` | `duration` | Timeout for initial sync of ServiceMonitor resources. | `1m` | no
 
 ## Blocks
 

internal/component/prometheus/operator/common/crdmanager.go

@@ -9,6 +9,8 @@ import (
 	"sync"
 	"time"
 
+	promk8s "github.com/prometheus/prometheus/discovery/kubernetes"
+
 	"github.com/go-kit/log"
 	"github.com/grafana/ckit/shard"
 	promopv1 "github.com/prometheus-operator/prometheus-operator/pkg/apis/monitoring/v1"
@@ -37,9 +39,6 @@ import (
 	"github.com/grafana/alloy/internal/util"
 )
 
-// Generous timeout period for configuring all informers
-const informerSyncTimeout = 10 * time.Second
-
 type crdManagerInterface interface {
 	Run(ctx context.Context) error
 	ClusteringUpdated()
@@ -332,7 +331,7 @@ func (c *crdManager) configureInformers(ctx context.Context, informers cache.Inf
 		return fmt.Errorf("unknown kind to configure Informers: %s", c.kind)
 	}
 
-	informerCtx, cancel := context.WithTimeout(ctx, informerSyncTimeout)
+	informerCtx, cancel := context.WithTimeout(ctx, c.args.InformerSyncTimeout)
 	defer cancel()
 
 	informer, err := informers.GetInformer(informerCtx, prototype)

internal/component/prometheus/operator/types.go

@@ -32,6 +32,8 @@ type Arguments struct {
 	RelabelConfigs []*alloy_relabel.Config `alloy:"rule,block,optional"`
 
 	Scrape ScrapeOptions `alloy:"scrape,block,optional"`
+
+	InformerSyncTimeout time.Duration `alloy:"informer_sync_timeout,attr,optional"`
 }
 
 // ScrapeOptions holds values that configure scraping behavior.
@@ -54,6 +56,7 @@ var DefaultArguments = Arguments{
 	Client: kubernetes.ClientArguments{
 		HTTPClientConfig: config.DefaultHTTPClientConfig,
 	},
+	InformerSyncTimeout: time.Minute,
 }
 
 // SetToDefault implements syntax.Defaulter.