Technology: distributor

Loki distributor encounters "empty ring" errors when attempting to send streams to pattern ingesters.This occurs when pattern ingestion is enabled in the configuration but no pattern-ingester pods are running or properly registered in the ring. The distributor's pattern-tee component cannot find anyavailable pattern ingesters to process pattern extraction, leading to high error spam in logs whilenormal log ingestion continues to function.

Grafana Mimir's distributor rejects incoming Prometheus series when the number of labelnames on a single series exceeds the configured per-tenant limit. When this occurs, logscontain the message "received a series whose number of labels exceeds the limit" and theaffected samples are dropped. This typically arises from excessive or dynamic labeling inscrape targets or relabeling rules that generate many unique label names per series.To adjust the per-tenant limit, configure the distributor with`-validation.max-label-names-per-series`. When deploying via the `mimir-distributed` Helmchart, set `mimir.structuredConfig.limits.max_label_names_per_series` to a higher value(default is 30). Increase limits cautiously to avoid cardinality explosions and memorypressure. Prefer reducing label names at the source where possible.