The Yapster back-end consists of the following services: API, Streaming, Storage, Persistent Messging, Transient Messaging. The services are deployed on EC2 instances running Ubuntu 14.04 LTS. Some of the services are deployed with Apache Mesos, Apache Marathon and Docker and some are run natively.
API
Closure - Netty / aleph / yada
Streaming
Clojure - Onyx
Storage
Apache Cassandra - Datastax Enterprise.
Cassandra is Yapster's primary datastore.
Nightly backups to S3.
Access to Cassandra is limited to the Yapster VPC by firewall.
Apache Kafka
Kafka is Yapster's primary messaging store.
Access to Kafka is limited to the Yapster VPC by firewall.