Loki is a multi-tenant system that supports applying limits to each tenant as a mechanism for resource management. The overrides-exporter module exposes these limits as Prometheus metrics in order to help operators better understand tenant behavior.

Context

Configuration updates to tenant limits can be applied to Loki without restart via the runtime_config feature.

Example

The overrides-exporter module is disabled by default. We recommend running a single instance per cluster to avoid issues with metric cardinality. The overrides-exporter creates one metric for every scalar field in the limits configuration under the metric loki_overrides_defaults with the default value for that field after loading the Loki configuration. It also exposes another metric for every differing field for every tenant.

Using an example runtime.yaml:

overrides:
  "tenant_1":
    ingestion_rate_mb: 10
    max_streams_per_user: 100000
    max_chunks_per_query: 100000

Launch an instance of the overrides-exporter:

loki -target=overrides-exporter -runtime-config.file=runtime.yaml -config.file=basic_schema_config.yaml -server.http-listen-port=8080

To inspect the tenant limit overrides:

$ curl -sq localhost:8080/metrics | grep override
# HELP loki_overrides Resource limit overrides applied to tenants
# TYPE loki_overrides gauge
loki_overrides{limit_name="ingestion_rate_mb",user="tenant_1"} 10
loki_overrides{limit_name="max_chunks_per_query",user="tenant_1"} 100000
loki_overrides{limit_name="max_streams_per_user",user="tenant_1"} 100000
# HELP loki_overrides_defaults Default values for resource limit overrides applied to tenants
# TYPE loki_overrides_defaults gauge
loki_overrides_defaults{limit_name="cardinality_limit"} 100000
loki_overrides_defaults{limit_name="creation_grace_period"} 6e+11
loki_overrides_defaults{limit_name="ingestion_burst_size_mb"} 6
loki_overrides_defaults{limit_name="ingestion_rate_mb"} 4
loki_overrides_defaults{limit_name="max_cache_freshness_per_query"} 6e+10
loki_overrides_defaults{limit_name="max_chunks_per_query"} 2e+06
loki_overrides_defaults{limit_name="max_concurrent_tail_requests"} 10
loki_overrides_defaults{limit_name="max_entries_limit_per_query"} 5000
loki_overrides_defaults{limit_name="max_global_streams_per_user"} 5000
loki_overrides_defaults{limit_name="max_label_name_length"} 1024
loki_overrides_defaults{limit_name="max_label_names_per_series"} 30
loki_overrides_defaults{limit_name="max_label_value_length"} 2048
loki_overrides_defaults{limit_name="max_line_size"} 0
loki_overrides_defaults{limit_name="max_queriers_per_tenant"} 0
loki_overrides_defaults{limit_name="max_query_length"} 2.5956e+15
loki_overrides_defaults{limit_name="max_query_lookback"} 0
loki_overrides_defaults{limit_name="max_query_parallelism"} 32
loki_overrides_defaults{limit_name="max_query_series"} 500
loki_overrides_defaults{limit_name="max_streams_matchers_per_query"} 1000
loki_overrides_defaults{limit_name="max_streams_per_user"} 0
loki_overrides_defaults{limit_name="min_sharding_lookback"} 0
loki_overrides_defaults{limit_name="per_stream_rate_limit"} 3.145728e+06
loki_overrides_defaults{limit_name="per_stream_rate_limit_burst"} 1.572864e+07
loki_overrides_defaults{limit_name="per_tenant_override_period"} 1e+10
loki_overrides_defaults{limit_name="reject_old_samples_max_age"} 1.2096e+15
loki_overrides_defaults{limit_name="retention_period"} 2.6784e+15
loki_overrides_defaults{limit_name="ruler_evaluation_delay_duration"} 0
loki_overrides_defaults{limit_name="ruler_max_rule_groups_per_tenant"} 0
loki_overrides_defaults{limit_name="ruler_max_rules_per_rule_group"} 0
loki_overrides_defaults{limit_name="ruler_remote_write_queue_batch_send_deadline"} 0
loki_overrides_defaults{limit_name="ruler_remote_write_queue_capacity"} 0
loki_overrides_defaults{limit_name="ruler_remote_write_queue_max_backoff"} 0
loki_overrides_defaults{limit_name="ruler_remote_write_queue_max_samples_per_send"} 0
loki_overrides_defaults{limit_name="ruler_remote_write_queue_max_shards"} 0
loki_overrides_defaults{limit_name="ruler_remote_write_queue_min_backoff"} 0
loki_overrides_defaults{limit_name="ruler_remote_write_queue_min_shards"} 0
loki_overrides_defaults{limit_name="ruler_remote_write_timeout"} 0
loki_overrides_defaults{limit_name="split_queries_by_interval"} 0

Alerts can be created based on these metrics to inform operators when tenants are close to hitting their limits allowing for increases to be applied before the tenant limits are exceeded.