// the find
seglo/kafka-lag-exporter
Monitor Kafka Consumer Group Latency with Kafka Lag Exporter
Kafka Lag Exporter scrapes consumer group offsets from Kafka brokers and exposes them as Prometheus metrics, including an estimated lag-in-seconds metric calculated via linear interpolation between offset snapshots. It's built on Akka Typed and Scala, targets Kubernetes/Strimzi setups primarily, but runs standalone too. If you run Kafka and care about whether your consumers are keeping up, this fills a gap the official Kafka metrics don't cover well.
The lag-in-seconds metric is the real reason to use this — raw offset lag is useless without knowing message production rate, and the interpolation approach is sound for most workloads. Strimzi auto-discovery is genuinely useful: drop it in and it finds your clusters without static config. The multi-sink support (Prometheus, InfluxDB, Graphite) means you're not locked into one monitoring stack. The Helm chart is well-structured with proper RBAC templates, whitelist/blacklist regex per cluster, and optional Redis persistence for the lookup table.
Last commit was February 2024 and the repo has been effectively abandoned since Lightbend handed it off — open issues pile up with no maintainer response. The Akka dependency is a liability: Lightbend relicensed Akka as BSL in 2022, meaning any version past 2.6 requires a commercial license, and this project is stuck on whatever Akka version it last pinned. The lag-in-seconds estimate breaks down with highly variable throughput or sparse partitions — it's linear interpolation between two poll points, so spiky workloads will produce garbage estimates. The in-memory lookup table defaults to 60 data points per partition, which at the default 30-second poll interval gives you only 30 minutes of history before old points are evicted, making the time-lag calculation unreliable for low-traffic topics.