Cortex is a horizontally scalable, highly available, multi-tenant long-term storage solution for Prometheus and OpenTelemetry Metrics.
Cortex solves the problem of scaling Prometheus beyond a single machine while maintaining high availability and supporting long-term metric retention. It achieves this by distributing metric ingestion and querying across a cluster, replicating data between machines for fault tolerance, and isolating data from multiple independent Prometheus sources within a single deployment. The tool supports multiple cloud storage backends including S3, GCS, Swift, and Microsoft Azure for persistent metric storage.
Teams should adopt Cortex when they need to scale Prometheus horizontally across multiple machines, require multi-tenant isolation for independent metric sources, or want to retain metrics long-term in cloud object storage. It suits organizations running Prometheus at scale in Kubernetes environments where a single Prometheus instance cannot handle the throughput or storage requirements. The project is particularly valuable for those seeking to consolidate multiple Prometheus instances into a unified, highly available cluster.
The project receives issue reports primarily from outside users rather than the core team, reflecting a substantial base of adopters running it in production. Responses to issues and pull requests typically arrive within one to two weeks. Work in the issue tracker centers on bug fixes, feature requests, and flaky test resolution, indicating active maintenance focused on stability and incremental improvements.
