Gain deep insights into application behavior
Cortex
Horizontally scalable, cloud-native Prometheus
Comparing Cortex to Prometheus, it is seen to offer the same powerful query language, data model and configurable alerts as Prometheus, but we added horizontal scalability and cloud-native storage for virtually infinite data retention.
Cortex was created by Weaveworks. Since September 2018, it is now a CNCF project with "incubating" status.

Features
Horizontally Scalable, Open Source
Built on Prometheus, Cortex is an open source project that adds horizontal scalability. While Prometheus can scale up to 1 million samples/sec on a single machine, with Cortex horizontal scalability is practically limitless.
Virtually Infinite Data Retention
Prometheus' local storage model limits the possible data retention and durability to that of a single machine. Cortex' use of cloud-native storage such as Amazon DynamoDB and S3 allow for virtually infinite data retention.
Prometheus Compatible
Cortex offers a Prometheus-compatible APIs and query language - PromQL. PromQL is a concise and expressive query language, allowing for powerful insight into your application's behavior. Due to Prometheus’ dimensional data model, you can slice, dice and drill down quickly into problems - enabling you to rapidly analyse resolve issues.
Designed for Microservices and Containers
In a constantly changing environment, you need alternative approaches to monitoring individual VMs or servers. Prometheus' service-discovery driven pull-based metrics system was designed for the dynamic nature of microservices. It lets you easily monitor your whole environment no matter how many moving parts.
Hundreds of Integrations
Instrument your application to create custom metrics using standard Prometheus client libraries, or take advantage of the extensive collection of Prometheus Exporters that collect data from existing applications like MySQL, Redis, Java, ElasticSearch and many more.