Cortex is a scalable, highly available, multi-tenant, long term storage for Prometheus. It is designed to reliably ingest and query millions of time series per second, while keeping the operational cost low. But if you try to get started, it is easy to get lost in the tens of different components and config options. In this talk, we will introduce Cortex and its architecture in an approachable way. We’ll start from the minimum setup required and we’ll iteratively cover the Cortex core design principles, sharding, replication, failure modes and a series of techniques employed by Cortex for accelerating PromQL queries. Finally, we’ll look at what the future holds for us and the upcoming features and improvements in Cortex. Cortex is an open source project, released under the Apache 2.0 license, and in the CNCF sandbox stage.