Cortex
Cortex is an open source, self-hosted system for horizontally scalable, highly available, multi-tenant long-term storage of Prometheus and OpenTelemetry metr…
What Cortex is
Cortex is an open source, self-hosted system for horizontally scalable, highly available, multi-tenant long-term storage of Prometheus and OpenTelemetry metrics. Prometheus can send samples through remote_write, and OpenTelemetry data can arrive through OTLP. Users query metrics with PromQL, including through Grafana, while an HTTP API handles time-series ingestion, queries, and cluster operations. Cortex can run as one binary for development or as independent microservices for production, including separate services in Kubernetes. Clustered deployments spread across machines and replicate data. Tenant isolation separates data and queries from independent Prometheus sources. Long-term storage integrations include S3, Google Cloud Storage, OpenStack Swift, and Microsoft Azure. Retention policies, TLS between components, supported server-side encryption, and Jaeger or OpenTelemetry tracing are included. Authentication and authorization are normally added through a reverse proxy. Cortex is licensed under Apache License 2.0.
Good
- Horizontal scaling across multiple machines
- Supports Prometheus remote_write and OTLP ingestion
- PromQL queries can be used through Grafana
- Offers several long-term object-storage integrations
- Supports retention policies and tenant isolation
Watch out
- Authentication and authorization require external configuration
- Components trust the X-Scope-OrgID tenant header
- SQL is not supported
- Regular release artifacts target Linux and macOS
Who it suits
Cortex suits operators who need self-hosted Prometheus or OpenTelemetry storage with horizontal scaling, tenant separation, and long-term retention. It fits teams comfortable configuring cluster security externally.
Verdict
Cortex provides scalable, multi-tenant metric storage with several deployment and storage choices. Its self-hosted model and externally configured security require operators to manage the installation and protection layers.
The facts
Each one read from Cortex's own pages, with the date it was checked.
What it does
- API
- Cortex exposes an HTTP API for pushing and querying time-series data and operating the cluster.checked 9 Oct 2026
- Deployment modes
- Cortex can run as a single binary for learning, development, and testing, or as independent microservices for production deployments.checked 9 Oct 2026
- Encryption
- Cortex supports TLS between its components and S3 server-side encryption using SSE-S3 or SSE-KMS for supported storage paths.checked 8 Oct 2026
- HTTP API
- Cortex exposes an HTTP API for pushing and querying time series data and operating the cluster.checked 8 Oct 2026
- Kubernetes
- The production-style microservices setup runs Cortex components as separate services in Kubernetes.checked 8 Oct 2026
- License
- Cortex is an open-source project licensed under Apache License 2.0.checked 9 Oct 2026
- Metrics and queries
- Prometheus sends metrics to Cortex using remote_write, and Grafana can query Cortex using PromQL.checked 9 Oct 2026
- Purpose
- Cortex is a horizontally scalable, highly available, multi-tenant long-term storage solution for Prometheus and OpenTelemetry metrics.checked 9 Oct 2026
- Query and ingestion
- Prometheus sends samples to Cortex through its remote write API, and users query metrics with PromQL.checked 8 Oct 2026
- Scalability and availability
- Cortex can run across multiple machines, and clustered deployments can replicate data between machines.checked 9 Oct 2026
- Scaling and availability
- Cortex can run across multiple machines in a cluster and replicate data between machines.checked 8 Oct 2026
- Security audit
- A third-party audit reported seven vulnerabilities, and the project says fixes shipped in Cortex v1.21.1, released June 4, 2026.checked 9 Oct 2026
- Security boundary
- Cortex requires authentication and authorization to be configured externally, typically through a reverse proxy.checked 8 Oct 2026
- Security configuration
- Cortex supports TLS between its components, while authentication and authorization are typically added through a reverse proxy.checked 9 Oct 2026
- Storage integrations
- Cortex supports S3, Google Cloud Storage, Swift, and Microsoft Azure for long-term metric storage.checked 9 Oct 2026
- Support
- The project directs users to its CNCF Slack channel, GitHub issues, and the cortex-users mailing list for questions.checked 9 Oct 2026
- Supported release targets
- Regular release artifacts include Linux and macOS binaries; other operating systems may work from source but are not regular supported release targets.checked 9 Oct 2026
- Tenant access limitation
- Cortex components trust the X-Scope-OrgID tenant header, so the security guide says an additional protection layer is needed to guard the installation.checked 8 Oct 2026
- Tenant isolation
- Cortex can isolate data and queries from multiple independent Prometheus sources in one cluster.checked 9 Oct 2026
- Tracing
- Cortex supports distributed tracing using Jaeger or OpenTelemetry.checked 8 Oct 2026
- What it does
- Cortex is a horizontally scalable, highly available, multi-tenant, long-term storage solution for Prometheus and OpenTelemetry metrics.checked 8 Oct 2026
The company
- Founded
- 2016checked 28 Sep 2026
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