Like Prometheus, but for logs!
Grafana Loki is a set of components that can be composed into a fully featured logging stack.
Unlike other logging systems, Loki is built around the idea of only indexing metadata about your logs: labels (just like Prometheus labels). Log data itself is then compressed and stored in chunks in object stores such as S3 or GCS, or even locally on the filesystem. A small index and highly compressed chunks simplifies the operation and significantly lowers the cost of Loki.