Chirp

A highly scalable, highly performant, highly blazing-fast Twitter clone.

Ansible

Contains all the setup/deployment files for all our cloud instances.

For deployment related notes, see the Ansible folder.

Packages

• chirp-api - API service
• chirp-api-nginx - Load balancer for chirp-api instances
• chirp-cassandra - Cassandra configuration
• chirp-elasticsearch - Elasticsearch config
• chirp-mongodb - MongoDB config for Chirp
• chirp-postfix - Postfix configuration
• chirp-ui - UI
• chirp-ui-static - UI that's already built (used for deployment)

Statistics

Load

Able to handle a load of 1000 concurrent users sending a total 200,000 requests over 10-12 minutes (about 250-300 requests per second). The tail latency (95th percentile) was around 150ms.

Hardware

Working hardware configuration to achieve the above stats (16 total instances).

• 2 vCPU load balancer
• 2 vCPU Elasticsearch instance
• 4 vCPU Cassandra cluster (2 CPU per node)
• 1 vCPU Postfix, Mail instance
• 6 vCPU MongoDB sharded cluster (3 config servers, 3 shards)
• 6 vCPU API webserver instances (1 sitting in the same instance as Postfix) (1 CPU each instance)

Maximize RAM for each instance (recommended 2 GB per core), but 1 GB/core works too.