feat(kafka): Replay kafka from last commit before allowing ingesters …

…to become ready (grafana#14330)

docs/sources/shared/configuration.md

@@ -839,6 +839,20 @@ kafka_config:
   # CLI flag: -kafka.producer-max-buffered-bytes
   [producer_max_buffered_bytes: <int> | default = 1073741824]
 
+  # The best-effort maximum lag a consumer tries to achieve at startup. Set both
+  # -kafka.target-consumer-lag-at-startup and -kafka.max-consumer-lag-at-startup
+  # to 0 to disable waiting for maximum consumer lag being honored at startup.
+  # CLI flag: -kafka.target-consumer-lag-at-startup
+  [target_consumer_lag_at_startup: <duration> | default = 2s]
+
+  # The guaranteed maximum lag before a consumer is considered to have caught up
+  # reading from a partition at startup, becomes ACTIVE in the hash ring and
+  # passes the readiness check. Set both -kafka.target-consumer-lag-at-startup
+  # and -kafka.max-consumer-lag-at-startup to 0 to disable waiting for maximum
+  # consumer lag being honored at startup.
+  # CLI flag: -kafka.max-consumer-lag-at-startup
+  [max_consumer_lag_at_startup: <duration> | default = 15s]
+
 # Configuration for 'runtime config' module, responsible for reloading runtime
 # configuration file.
 [runtime_config: <runtime_config>]

pkg/ingester/ingester.go

@@ -300,7 +300,7 @@ type Ingester struct {
 }
 
 // New makes a new Ingester.
-func New(cfg Config, clientConfig client.Config, store Store, limits Limits, configs *runtime.TenantConfigs, registerer prometheus.Registerer, writeFailuresCfg writefailures.Cfg, metricsNamespace string, logger log.Logger, customStreamsTracker push.UsageTracker, readRing ring.ReadRing, partitionRingWatcher *ring.PartitionRingWatcher) (*Ingester, error) {
+func New(cfg Config, clientConfig client.Config, store Store, limits Limits, configs *runtime.TenantConfigs, registerer prometheus.Registerer, writeFailuresCfg writefailures.Cfg, metricsNamespace string, logger log.Logger, customStreamsTracker push.UsageTracker, readRing ring.ReadRing, partitionRingWatcher ring.PartitionRingReader) (*Ingester, error) {
 	if cfg.ingesterClientFactory == nil {
 		cfg.ingesterClientFactory = client.New
 	}

pkg/ingester/kafka_consumer.go

@@ -3,7 +3,7 @@ package ingester
 import (
 	"context"
 	"errors"
-	math "math"
+	"math"
 	"sync"
 	"time"
 

pkg/kafka/config.go

@@ -36,18 +36,14 @@ const (
 	// in the worst case scenario, which is expected to be way above the actual one.
 	maxProducerRecordDataBytesLimit = producerBatchMaxBytes - 16384
 	minProducerRecordDataBytesLimit = 1024 * 1024
-
-	kafkaConfigFlagPrefix          = "ingest-storage.kafka"
-	targetConsumerLagAtStartupFlag = kafkaConfigFlagPrefix + ".target-consumer-lag-at-startup"
-	maxConsumerLagAtStartupFlag    = kafkaConfigFlagPrefix + ".max-consumer-lag-at-startup"
 )
 
 var (
 	ErrMissingKafkaAddress               = errors.New("the Kafka address has not been configured")
 	ErrMissingKafkaTopic                 = errors.New("the Kafka topic has not been configured")
+	ErrInconsistentConsumerLagAtStartup  = errors.New("the target and max consumer lag at startup must be either both set to 0 or to a value greater than 0")
+	ErrInvalidMaxConsumerLagAtStartup    = errors.New("the configured max consumer lag at startup must greater or equal than the configured target consumer lag")
 	ErrInvalidProducerMaxRecordSizeBytes = fmt.Errorf("the configured producer max record size bytes must be a value between %d and %d", minProducerRecordDataBytesLimit, maxProducerRecordDataBytesLimit)
-
-	consumeFromPositionOptions = []string{consumeFromLastOffset, consumeFromStart, consumeFromEnd, consumeFromTimestamp}
 )
 
 // Config holds the generic config for the Kafka backend.
@@ -68,6 +64,9 @@ type Config struct {
 
 	ProducerMaxRecordSizeBytes int   `yaml:"producer_max_record_size_bytes"`
 	ProducerMaxBufferedBytes   int64 `yaml:"producer_max_buffered_bytes"`
+
+	TargetConsumerLagAtStartup time.Duration `yaml:"target_consumer_lag_at_startup"`
+	MaxConsumerLagAtStartup    time.Duration `yaml:"max_consumer_lag_at_startup"`
 }
 
 func (cfg *Config) RegisterFlags(f *flag.FlagSet) {
@@ -91,6 +90,10 @@ func (cfg *Config) RegisterFlagsWithPrefix(prefix string, f *flag.FlagSet) {
 
 	f.IntVar(&cfg.ProducerMaxRecordSizeBytes, prefix+".producer-max-record-size-bytes", maxProducerRecordDataBytesLimit, "The maximum size of a Kafka record data that should be generated by the producer. An incoming write request larger than this size is split into multiple Kafka records. We strongly recommend to not change this setting unless for testing purposes.")
 	f.Int64Var(&cfg.ProducerMaxBufferedBytes, prefix+".producer-max-buffered-bytes", 1024*1024*1024, "The maximum size of (uncompressed) buffered and unacknowledged produced records sent to Kafka. The produce request fails once this limit is reached. This limit is per Kafka client. 0 to disable the limit.")
+
+	consumerLagUsage := fmt.Sprintf("Set both -%s and -%s to 0 to disable waiting for maximum consumer lag being honored at startup.", prefix+".target-consumer-lag-at-startup", prefix+".max-consumer-lag-at-startup")
+	f.DurationVar(&cfg.TargetConsumerLagAtStartup, prefix+".target-consumer-lag-at-startup", 2*time.Second, "The best-effort maximum lag a consumer tries to achieve at startup. "+consumerLagUsage)
+	f.DurationVar(&cfg.MaxConsumerLagAtStartup, prefix+".max-consumer-lag-at-startup", 15*time.Second, "The guaranteed maximum lag before a consumer is considered to have caught up reading from a partition at startup, becomes ACTIVE in the hash ring and passes the readiness check. "+consumerLagUsage)
 }
 
 func (cfg *Config) Validate() error {
@@ -103,6 +106,12 @@ func (cfg *Config) Validate() error {
 	if cfg.ProducerMaxRecordSizeBytes < minProducerRecordDataBytesLimit || cfg.ProducerMaxRecordSizeBytes > maxProducerRecordDataBytesLimit {
 		return ErrInvalidProducerMaxRecordSizeBytes
 	}
+	if (cfg.TargetConsumerLagAtStartup == 0 && cfg.MaxConsumerLagAtStartup != 0) || (cfg.TargetConsumerLagAtStartup != 0 && cfg.MaxConsumerLagAtStartup == 0) {
+		return ErrInconsistentConsumerLagAtStartup
+	}
+	if cfg.MaxConsumerLagAtStartup < cfg.TargetConsumerLagAtStartup {
+		return ErrInvalidMaxConsumerLagAtStartup
+	}
 
 	return nil
 }